This paper offers a short overview of epoxy resins, encompassing their diverse characteristics, variants, chemical modifications, curing processes, and intriguing electrical properties. Epoxies, valued for their multifunctional attributes, serve as fundamental materials across industries. In the realm of dielectric strength, epoxy resins play a crucial role in electrical insulation. This paper discusses the mechanisms governing dielectric breakdown, strategies to enhance dielectric strength, and the impact of various fillers and additives on insulation performance. Through an exploration of recent research and advancements, this paper delves into the spectrum of epoxy properties, the array of subspecies and variants, their chemical adaptability, and the intricacies of curing. The examination of electrical resistance and conductivity, with a focus on their frequency-dependent behavior, forms a pivotal aspect of the discussion. By shedding light on these dimensions, this review provides a concise yet holistic understanding of epoxies and their role in shaping modern materials science. The evolving landscape of electronics and microprocessor technology, characterized by increasingly potent components within devices, necessitates the advancement of highly efficient composite materials. This also calls for the innovation of robust resins  that are capable of performing reliably under extreme conditions, including elevated temperatures, exposure to solar radiation, and high humidity levels. These materials are essential for effectively sealing electronic devices that are made from diverse substrates such as plastic, brass, aluminum, copper, and carbon steels. Additionally, they play a vital role in providing protective coatings for structural materials, safeguarding them against various forms of impact and shock ,2.The range of use is determined by the parameters of epoxy resins (ERs): thermal conductivity and electrical conductivity. Ensuring reliable adhesion on boards formed from fiberglass with plastic and metal, as well as a combination of dielectric properties with light transmission, are in demand in microelectronics and electrical engineering .Excellent dielectric/electrical insulating properties;Ultra-high water resistance;Chemical resistance ;High mechanical properties ;The highest adhesion ;Low shrinkage during curing (minor deformations);High stability;Increased heat resistance ;The absence of volatile products and the release of side substances during curing;A low coefficient of shrinkage in the course of hardening;Minimum creep under load;Low odor;Ease of production and versatility of processing processes;Small weight of the finished product;Durability and shelf life;Environmental friendliness;Safety.The widespread use of epoxy resins in the production of electronic components is due to their high manufacturability and the unique set of performance characteristics of their curing products ,5,6,7:ExThe complex of unique physicomechanical  and physicochemical properties  of epoxy resin allows products based on them to cover a wide range of applications in various fields of electrical and radio engineering. Scientific and technical research that focuses on the development of the most specialized coatings (epoxy fills) that are resistant to highly aggressive environments, improving the properties of epoxy resin as a dielectric , and satisfying certain operating conditions is steadily growing . At the present stage of the development of space technology, it has been established that the most dangerous factor for existing spacecraft is the functional damage to on-board radio-electronic equipment from ionizing and secondary electromagnetic radiation. The impact of such radiation leads to structural changes in materials, the occurrence of ionization, heating, the appearance of induced radioactivity, and other phenomena that disrupt physical and chemical processes in technical devices .After curing, epoxy resins act as a high-quality insulator that provides the sealing  of conductive circuits from the effects of electrostatic discharge, high temperatures, vibrations, moisture, chemicals, and shocks in electrical and radio engineering products.Epoxy resin hold significant importance within the electronics industry and find applications in a range of equipment including motors, generators, transformers, switchgear, bushings, and insulators. These epoxy resins offer outstanding electrical insulation properties, effectively shielding electrical components from potential issues like short circuits, dust ingress, and moisture exposure .In addition, metal-filled polymers are widely adopted for electromagnetic interference shielding . Epoxy mAs sealants, epoxy resins (compounds) remain popular among polymeric materials in terms of application. To date, due to the thermodynamic and reactive compatibility of epoxy oligomers, a huge number of compounds have been synthesized, and various hardeners have been successfully used to turn thermoplastic resins into infusible ones .Radio, electrical industry, electronics, and microelectronics ;The rocket and space industry;The energy industry;The engineering industry (production of components);Construction ; sealants; adhesives; the waterproofing of floors, walls of basements, and swimming pools; the impregnation of concrete, brick, wood, and mortar; the successful replacement of bitumen—bitumen–epoxy composition);The textile and leather industries;The furniture industry (designer furniture);Arts and crafts ;The domestic sphere and household .ERs are one of the most important class of thermoplastics and the following broad areas of their application are listed below ,15,16,17Printed circuit boards (PCBs): epoxy resin is used as a substrate material for printed circuit boards, providing insulation between board layers and protecting components from environmental influences;Sealing: epoxy resin is used to seal electronic components, protecting them from environmental influences such as moisture and dust;Adhesives: epoxy resin is used as an adhesive in the production of electronic components, and is a sensitive strong bond between components and substrates;Coatings: epoxy resin is used as a coating material for electronic components, providing protection against moisture, chemical compounds, and abrasion.Their implementations, specifically in the production of electronic components, are the following ,19,20:PrThe use of epoxy resin in the manufacturing of electronic components typically involves a curing process, in which the resin is mixed with hardener and then subjected to heating or ultraviolet radiation to initiate a curing reaction. Amines were among the first epoxy resin hardeners, and they have retained a leading position among all reagents of this type ,22.Vacuum impregnation: this involves placing the electronic component within a vacuum chamber, where epoxy resin is drawn into the component under vacuum pressure;Pouring: in this method, an electronic component is situated in a mold and epoxy resin is poured over it, effectively sealing the component;Dispensing: epoxy is administered onto an electronic component using a dispensing machine;Spray coating: here, epoxy resin is applied onto an electronic component via a spray gun.The curing process can be carried out using various technologies, including the following :Vacuum iThe cross-linking or curing process is usually slow, especially when small volumes of resin are involved. Fast curing hardeners can be used, but they generate a lot of heat during the process, resulting in a strong exothermic reaction that can damage electronic components and cause high mechanical stress not only on them, but also on the circuit .The process of curing epoxy polymers involves the utilization of a hardening agent, typically a primary or secondary amine or an acid anhydride. This agent serves as a binding element among the distinct macromolecules. In order to facilitate the creation of a three-dimensional network, which is crucial for conferring the ultimate product with the characteristics of an impenetrable and non-soluble material , novolac (phenolic and cresol), aliphatic , glycidyl, and acrylic epoxy. Dozens of their subspecies are known, including light-cured and water-borne ones (their widespread introduction is hindered by high cost) .An integral component of epoxy resin, as a two-component thermosetting polymer, is a hardener, of either the cold or hot type, which determines the further technical characteristics of the epoxy . Their percentage ratio is extremely important for the quality performance of the composition. The main part of the additives are the plasticizers: dibutyl phthalate, diethylene glycol (DEG-1), diphenyl phthalate, polyesters, styrene oxide, and thiokol, and the inclusion of silicon components in the mixture determines the resistance to heat.The chemical modification of polymers is carried out by introducing small fragments of a different nature into the composition of macromolecules. Changing the chemical nature of oligomers and hardeners makes it possible to increase the length of the molecular chain of the oligomer and hardener to vary the structure of the internodal sections of the cured system, to modify the end groups of oligomer macromolecules, thereby changing the macroscopic properties of the epoxy polymer. The introduction of reactive additives that are capable of entering into a chemical reaction with the polymer makes it possible to regulate the physical and mechanical properties of epoxides, such as heat resistance, aging resistance, etc., in a wide range .It is known from the literature that dispersed fillers cause a change in almost all properties of liquid and cured epoxy compositions: they increase the viscosity of the binder, and reduce its mobility and viability ,31,32, aIn the study and regulation of the dielectric properties of epoxy oligomers, using various thinners, fillers, curing accelerators, and plasticizers, special attention is paid to the molecular structure of the resulting composites.The composition (epoxy–bakelite or epoxy–phenolic) has very high dielectric, and especially mechanical, properties, water resistance, and heat resistance. These epoxy compositions are widely used for the production of electrical insulating varnishes and adhesives. Polysulfide resins (thiokols) are also used to cure epoxy resins. The resulting compositions have high elasticity and impact strength, and good dielectric properties are applied to the production of elastic filling compounds. Epoxy–polyester compositions with the introduction of fillers are widely used for the manufacture of casting compounds for the cast insulation of windings of electrical machines, apparatus, and transformers . PlasticDue to their low viscosity, they are called active ES thinners, since they are able to replace solvents in the composition of epoxy compositions and copolymerize with ES without releasing by-products. There is a “chemical” modification of the epoxy composition due to the incorporation of flexible fragments into a rigid polymer network and an increase in the molecular weight of the segment ,43,44. EThe development of new composite materials has expanded the production and use of epoxy resins by several orders of magnitude. Depending on the use, the composition and the amount of filler  are taken into account; thus, the dielectric and physicomechanical properties of cured epoxy resins can vary widely. Depending on the number of epoxy groups, uncured epoxy resins are in a liquid or solid state. They are popular and cover a wide range of applications (from 70 to 90%), such as epoxy–diane resins (diphenylol propane) based on bisphenol A.The curing agent polyaminoamide is utilized for curing liquid, low-molecular-weight epoxy resins and their compounds. The weight ratio of epoxy resin to curing agent can be adjusted to achieve specific properties in the final cured material. A higher content of the curing agent (above 70% by weight) results in a more elastic and impact-resistant cured resin. However, this comes at the expense of reduced hardness and resistance to high temperatures (attributed to a lower glass transition temperature). This curing agent is suitable for applications requiring cold-cure epoxy resin, where the curing process occurs at room temperature. It is important to note that, according to the product’s safety data sheet, this substance is caustic, may cause skin irritation, and has the potential for sensitization .When epoxy resins are exposed to compounds containing a mobile hydrogen atom, they are able to cure with the formation of three-dimensional infusible and insoluble products with high physical and technical properties. Thus, it is not the epoxy resins themselves that are thermosetting, but their mixtures with hardeners and catalysts. Various substances are used as hardeners for epoxy resins: diamines , carboxylic acids, or their anhydrides .High adhesion to the surface of the material on which they harden;High dielectric properties;High mechanical strength;Good chemical resistance and water resistance;Hardening does not emit volatile products and are characterized by low shrinkage (2–2.5%) .Epoxy resins mixed with the above hardeners form thermoset compositions with valuable properties:Recently, the traditionally used non-reactive modifiers , which, along with an increase in the elasticity of epoxy materials, lead to a decrease in network density and are able to migrate from the material during operation and increase shrinkage, are being replaced by modifiers that can be embedded in the epoxy matrix. In this case, preference is given to those modifiers that do not lead to the formation of by-products of the reaction and do not increase the number of volatiles released. Such modifiers include, in particular, mono- and polyfunctional low-molecular-weight and oligomeric epoxy compounds, as well as mono- and polyfunctional cyclocarbonates .The study of the phenomenon of heat transfer is very important in the manufacturing of composite materials for protective screens. We consider multilayer plates as radiation shields, which compete with single-layer plates made from the same complex composite materials. Samples in the form of thin plates of epoxy resin grade ED-20 with a filler of soot, graphite, and aluminum powder were studied. Analyzing the results, we can conclude that the introduction of graphite and aluminum powder can significantly increase the effective thermal conductivity of the tested samples. The values of thermal conductivity with carbon black are ambiguous, and to determine the reason for this behavior, an X-ray diffraction study of both the carbon black and graphite that were used is necessary .Dielectric analysis (DEA) is a method used to monitor the curing process of polymer materials. It involves the measurement of electrical properties, such as dielectric permittivity (or capacitance) and dielectric loss (or conductivity), as a function of time, temperature, or frequency during the curing process. DEA is particularly useful for materials like thermosetting resins, which undergo a chemical transformation during the curing process. It provides a non-destructive and real-time method to monitor and control the curing process, ensuring that the final material possesses the desired properties ,52,53,54In the context of the dielectric analysis (DEA) method, the ionic viscosity parameter and the actual viscosity of a system are related through the dielectric properties of the material being analyzed. Specifically, the ionic viscosity parameter is related to the ion mobility of the material, which in turn can affect its dielectric properties. The actual viscosity of a material refers to its resistance to flow or deformation. It is a measure of the material’s mechanical behavior. The ionic viscosity parameter is, on the other hand, related to ion mobility and electrical behavior; the actual viscosity is related to the material’s mechanical response. In some cases, there may be a correlation between the ionic viscosity parameter and the actual viscosity, especially if the movement of ions significantly impacts the flow behavior of the material ,54,55.There are several important parameters of the curing process; among them are the gelation time and curing degree. In brief, the curing degree represents the extent of polymerization or cross-linking that has occurred, while the gelation time is the point in time at which a material starts to transition from a liquid or gel to a solid. Both parameters are significant in various industries where the precise control of material properties is essential ,57.The curing process of a thermoset involves a complex series of chemical reactions. Primarily, both gelation and vitrification play pivotal roles . This prIt is worth mentioning that it is also possible to monitor the curing process of a composite material using a multi-channel dielectric analysis (DEA) and potentially correlate it with the thickness of the composite. The thickness of a composite material can influence the curing process. Thicker sections may cure differently than thinner ones due to variations in heat distribution, mass, and heat dissipation. Monitoring multiple channels allows for a more comprehensive understanding of how thickness impacts the curing process. Variations in thickness can lead to non-uniform curing. A multi-channel DEA can detect inhomogeneities in the curing process, providing valuable insights into how different parts of the composite are curing ,60.When modified with various substances, the properties of the polymer matrix (intermolecular interactions) change, affecting the kinetics and mechanisms of molecular processes, which significantly affect the technological and electrical properties of epoxy compounds.2O3 powder of three different sizes was introduced into the mixture of an epoxy compound ) without chemical modifications of the filler surface, as well as a combination of micro- and nano-sized fillers without changing the total percentage of the filler, the λ values of the epoxy compound increased when moving from the nano to the micro-sized filler. When half of the Al2O3 particles with a size of 100 μm in the epoxy compound are replaced by particles with a size of 25 nm, there is a significant decrease in the effective thermal conductivity. This may be due to a decrease in the number of large particles of the highly thermally conductive filler necessary to create a heat-conducting cluster [The works ,62 descr cluster .2 concentration. Initially, the electric breakdown strength of nano-SiO2-enhanced RIP (resin-impregnated insulation paper) experiences an ascent with rising content, reaching its zenith at 2 wt%. Subsequently, it diminishes for 3 and 4 wt%. In comparison to unmodified RIP, the maximum DC breakdown strength saw an increment of 10.6% [of 10.6% .Moreover, if we follow the arrow in 2O3, TiO2, AlN, BN, or a combination thereof. Preference is given to particles with an average size of 500 µm or less.There is a patent that describes a method for obtaining an electrically insulating material with excellent insulating properties . The eleThe patent  describeCarbon–polymer composites are widely used in the creation of new structural materials for conductive, heat-absorbing, and shielding coatings. In recent years, special attention has been paid to the study of polymer composite materials based on electrically conductive nanosized fillers, such as carbon nanotubes (CNTs) and nanofibers (CNFs) ,69.In , the repIn , the resDuring the curing of the epoxy oligomer, its phase state changes and the material initially passes from a liquid to a gel-like state and then to a solid ,73,74. T2O3 and iridium orthosilicate IrSiO4 (constituting 72.1% of the composition), both in the presence and absence of a modifier, tetrabutoxytitanium (TBT) (see The study  examinedTBT) see .The incorporation of fillers or modifiers into the polymer has a discernible impact on thermal conductivity. The numerical value λ of the composite material is influenced not only by the quantity of the added component but also by its interaction with the polymer phase.2O3 significantly augments the thermal conductivity of the composite material, exhibiting a threefold increase across the entire temperature range (40–190 °C) while maintaining a consistent curve profile. Similarly, the use of iridium orthosilicate IrSiO4 as a filler doubles the thermal conductivity of the cured epoxy composition within the specified temperature range (40–180 °C). On the other hand, the introduction of tetrabutoxytitanium as a modifier in the composite material composition does not notably alter the temperature-dependent behavior of thermal conductivity.The results demonstrate that the inclusion of aluminum oxide Alk) could represent a significant hindrance to heat transfer within PNCs.According to , the sliThe authors of  experimeThe investigation of , in whicThe incorporation of nano-fillers has been widely suggested as a means to improve the dielectric properties of high voltage polymeric insulation, although there are conflicting reports in the literature. According to , the potThis study, based on , revealsThe purpose of this work  was the To create polymer composites that reduce the impact of electromagnetic fields on electronic components of computer technology and biological objects, it is necessary to obtain materials with specified values of dielectric permittivity, a dielectric loss tangent, and electrical conductivity, which are determined by the operating frequency range of the nanocomposites.Epoxy binders have the advantage of low shrinkage and high strength characteristics. However, scientific and technological progress constantly increases operational requirements, so polymers must be modified. The most promising are composite materials with nanosized fillers—nanocomposites ,46,47,84The research of  aimed toThe characteristics of the composite depend on the particle size of the filler. Large filler particles (315–500 microns) are isolated by a dielectric layer, so they have poor contact with each other. The maximum value of the dielectric constant is observed with the introduction of particles of a minimum size of 63–80 µm .In , the autComposites containing SWCNTs exhibit their lowest electrical conductivity when operating in the region above the percolation threshold. The rationale behind this observation lies in the fact that SWCNTs, being the smallest in size, consequently offer the highest number of contact regions .In a different study documented in , the resThe incorporation of carbon fillers into the polymer matrix opens up avenues for obtaining materials with diverse properties. Parameters such as the particle shape, aspect ratio, and the evenness of their dispersion within the polymer matrix play pivotal roles in determining both the percolation threshold and the electrical conductivity of the resultant composites. Hence, carbon particles hold significant promise as fillers for crafting composite materials with tailored permittivity values, influenced by the operational frequency range of these nanocomposites .The research of  explored2/g, 0.05 m2/g, and 0.025 m2/g, respectively.The study of  delved iThe authors of  investigThe flexural properties of composites composed of multi-walled carbon nanotubes (MWCNTs) and epoxy resin were found to be closely linked to two key factors: the dispersion of the MWCNTs within the matrix and the interactions occurring at the interface between the MWCNTs and the resin matrix . Figure The flexural strength and modulus of the pristine resin were measured at 122 MPa and 2.6 GPa, respectively. In comparison, the MWCNT-NH2 reinforced nanocomposites exhibited improved flexural properties, with a strength reaching 135 MPa and a modulus of 3.2 GPa, representing an increase of 11.0% and 23.1% compared to the neat resin.Conversely, the MWCNT/epoxy nanocomposites treated with surface sizing demonstrated superior flexural characteristics. This enhancement is attributed to the improved dispersion and increased wettability achieved by using epoxy-sizing MWCNTs, as opposed to MWCNT-NH2. The flexural strength and modulus of the MWCNT-BeGE/epoxy nanocomposites could reach 150 MPa and 3.6 GPa, respectively, marking a significant improvement of 22.9% and 37.8% compared to the neat epoxy. Furthermore, when compared with the MWCNT-BuGE/epoxy nanocomposites featuring the same MWCNT content, the MWCNT-BeGE/epoxy nanocomposites displayed a 7.3% increase in strength and a 7.7% increase in modulus, demonstrating that the presence of benzene rings in the surface sizing offered a more effective local load-transfer mechanism between the MWCNTs and the epoxy matrix.Epoxy polymers are one of the most commonly used polymeric materials in the production of composites. This is due to the properties of epoxy materials, such as high strength, rigidity, chemical resistance, low weight, and a low residual stress in epoxy products due to the low degree of the shrinkage of materials during curing ,94. Epox6 ohm∙m to 109 ohm∙m) and insulating (with a resistance of >109 ohm∙m). Another important field in the application of polymer composites is for protection against electromagnetic radiation [However, for application in some areas, composites based on polymeric materials must have electrical conductivity. One of the important areas for the application of polymer composite materials is the creation of coatings that prevent the accumulation of electrostatic charge (antistatic coatings). In accordance with the international standard IEC 61340-5-1 , coatingadiation . To impradiation .The use of nanosized additives makes it possible to achieve the required conductivity of the polymer composite with much lower amounts of the introduced additive. For these purposes, carbon nanotubes are used: multi-walled , single-The introduction of graphene particles into the epoxy matrix has little effect on the electrical conductivity and mechanical properties of the composites. The addition of graphene particles to composites containing carbon nanotubes improves their electromagnetic shielding efficiency without significantly affecting their strength .In the study of , it was The objective of the study described in reference  was to fIn the study  a range As one of the ways to increase the strength of epoxy resins, the addition of carbon nanomaterials (graphenes and carbon nanotubes) is considered ,109. CNTScientists from Rice University  have devThe complex of the unique physicomechanical and physicochemical properties of epoxy resin allows products based on them to cover a wide range of applications in various fields of electrical and radio engineering. Scientific and technical research that focuses on the development of the most specialized coatings (epoxy fills) that are resistant to highly aggressive environments, improving the properties of epoxy resin as a dielectric , and satisfying certain operating conditions is steadily growing.In conclusion, the resonance of epoxies as vital materials across industries is unmistakable. Their adaptability, versatility, and responsiveness to chemical and electrical factors render them as more than mere compounds—they are dynamic components that shape our technological landscape. By embracing their multifunctionality, researchers and practitioners stand poised to unlock the potential of epoxies in domains ranging from electronics to aerospace, ushering in a future where these remarkable materials continue to be at the forefront of innovation and progress.


As one of the most frequently perturbed pathways in human tumors, many drugs have been developed to target the PI3K/AKT pathway. However, most of them have failed in clinical trials. Notably, the selection of patients for these trials has often relied on the presence of PIK3CA hotspot mutations.In the second example, our proteogenomic analysis revealed the mechanisms behind the accumulation of β‐catenin protein and resistance to Wnt/FZD antagonists in CTNNB1 hotspot‐mutated tumors, achieved through the dephosphorylation of β‐catenin at S45. Hotspot mutations within exon 3 of CTNNB1 result in a significant upregulation of the WNT/β‐catenin pathway and are associated with poorer survival and recurrence outcomes. Consequently, many drugs have been designed to target upstream regulators of β‐catenin, including DKK and FZD. These drugs function by releasing the β‐catenin phosphorylation complex which facilitates the phosphorylation of β‐catenin. Subsequently, the phosphorylated β‐catenin undergoes degradation. While the most significantly up‐regulated protein in CTNNB1 hotspot mutated tumors is DKK4, an inhibitor of the WNT pathway,Additional findings include: (1) A negative correlation was observed between MYC activity and treatment with the anti‐diabetic drug metformin, which has been shown to improve overall survival of diabetic EC patients. As many non‐diabetic patients displayed elevated MYC activity, these results suggest a role for metformin treatment in non‐diabetic EC patients. (2) Targeted Selected Reaction Monitoring analysis identified two peptides that can accurately predict activity of the antigen processing and presentation machinery, providing candidate biomarkers to inform selection of EC patients for treatment with immune checkpoint inhibitors. (3) EC tumors with gain of chromosome 1q have lower immune activity and decreased disease‐free survival. EC cell lines in DepMap with PARP1 amplification are more sensitive to PARP inhibition. Based on these findings, PARP1 gain is a potential biomarker for PARP inhibitor therapy of EC. (4) Non‐negative matrix factorization clustering of glycopeptides groups tumors into four subtypes that are distinct from the multi‐omics clusters. (5) Deep learning models accurately predicted EC subtypes and mutations from analysis of histopathology images, which may be useful for rapid diagnosis of certain subtypes as a complement of genome sequencing.In summary, this study identified molecular markers and mechanisms that can be further investigated to guide patient stratification for precision treatment of EC. Notably, proteomics and phosphoproteomics played a key role in the path to these findings. Furthermore, these findings underscore the promise of proteogenomics, an integration of proteomics, transcriptomics, and genomics, for providing profound insights in precision oncology.The authors declare no conflicts of interest.


In this work, KH550 (γ-aminopropyl triethoxy silane)-modified hexagonal boron nitride (BN) nanofillers were synthesized through a one-step ball-milling route. Results show that the KH550-modified BN nanofillers synthesized by one-step ball-milling (BM@KH550-BN) exhibit excellent dispersion stability and a high yield of BN nanosheets. Using BM@KH550-BN as fillers for epoxy resin, the thermal conductivity of epoxy nanocomposites increased by 195.7% at 10 wt%, compared to neat epoxy resin. Simultaneously, the storage modulus and glass transition temperature (Tg) of the BM@KH550-BN/epoxy nanocomposite at 10 wt% also increased by 35.6% and 12.4 °C, respectively. The data calculated from the dynamical mechanical analysis show that the BM@KH550-BN nanofillers have a better filler effectiveness and a higher volume fraction of constrained region. The morphology of the fracture surface of the epoxy nanocomposites indicate that the BM@KH550-BN presents a uniform distribution in the epoxy matrix even at 10 wt%. This work guides the convenient preparation of high thermally conductive BN nanofillers, presenting a great application potential in the field of thermally conductive epoxy nanocomposites, which will promote the development of electronic packaging materials. Therefore, developing TMMs with high thermal conductivity is of great importance for the electronic and electrical industry.The rapid development of modern electronic devices toward high integration, high power density, and miniaturization presents an increasing requirement for heat dissipation, which makes it urgent to develop high thermally conductive materials for thermal management applications ,2,3,4. C2O3, BN, etc.) [−1K−1 [Incorporating high-thermal-conductivity filler into epoxy matrix is a widely used method for improving the thermal conductivity of epoxy resin ,13. TypiN, etc.) ,19. Comp) [−1K−1 ,21. Neve) [−1K−1 .To date, different means have been explored for the preparation of BN nanosheets, such as mechanical ball-milling , chemica2O) and absolute ethyl alcohol (CH3CH2OH) containing KH550, followed by performing the ball-milling process. On one hand, the -NH2 group (lewis base) of KH550 can interact with B atom (Lewis acid) of BN; on the other hand, the mechanical impact and shear forces generated by grinding balls could make KH550 molecules easy to insert the gap of BN layers. As a result, a high yield of BN nanosheets was obtained, and the KH550 were also grafted onto the surface of BN nanosheets under the action of ball-milling internal heat. Using ball-milled KH550-modified BN as fillers, epoxy nanocomposites were prepared after blending and curing, and the thermal conductivity and dynamic thermomechanical property of epoxy nanocomposites were investigated.Recently, Chen et al.  developeBN powders , γ-aminopropyl triethoxy silane , and absolute ethyl alcohol (99.7%) were purchased from McLean Biochemical Technology Co., Ltd. . Epoxy resin (E-51), methylhexahydrophthalic anhydride (MHHPA), and 2.4.6-Tri(dimethylaminomethyl)Phenol (DMP-30) were provided by Haining Hailong Chemical Co., Ltd. . All raw materials or reagents were not further purified before use.2O and CH3CH2OH (volume ratio: 3:7) containing 1% KH550 into the ball-grinding tank at a ratio of 0.05 g·mL−1 [2O and CH3CH2OH. In addition, the BM-BN were also post-modified with 1% KH550 solution at 60 °C for 2 h to obtain the conventional KH550-modified BN nanofillers (BM-KH550-BN).Raw BN (R-BN) powders were added into a stainless steel ball grinding tank containing 50 stainless steel grinding balls, followed by pouring a mixed solution of H5 g·mL−1 . Subsequ−1, and then the epoxy resin was added into the BN dispersion. With vigorous stirring, the mixed solution of BN/epoxy was reduced-pressure distilled at 60 °C until the absolute ethyl alcohol was fully evaporated. Afterwards, the MHHPA and DMP-30 were added into the mixed solution in sequence, followed by stirring for 30 min at room temperature in a vacuum. Finally, the BN/epoxy nanocomposites were obtained after BN/epoxy mixture was cured at 120 °C for 2 h in stainless steel mold. Herein, the weight ratio of epoxy resin, MHHPA, and DMP-30 was set to 100:85:0.8, and the weight content of BN nanofillers was set to 1%, 4%, 7%, and 10%.The desired ratios of BN nanofillers were ultrasonically dispersed into absolute ethyl alcohol at a concentration of 0.05 g·mL−1) were taken on a white paper by a smartphone . Fourier-transform infrared (FTIR) spectra of BN nanofillers were recorded at room temperature by an infrared spectrometer  with the range from 400 cm−1 to 4000 cm−1. The thermogravimetric analysis (TGA) was performed by a thermal gravimetric analyzer , Q50) at a heating rate of 5 °C/min from 30 to 800 °C under a nitrogen atmosphere according to the ASTM E1131 standard. Thermal conductivity of BN/epoxy nanocomposites (50 mm in diameter and 20 mm in height) was tested with a quick thermal conductivity meter . The dynamic thermomechanical properties of BN/epoxy nanocomposites were measured with DMA 850 (TA Instruments) according to the ASTM standard D4065-94. The nanocomposite samples were cut into strip-shaped specimens (60 × 10 × 4 mm3) to match with machine. A temperature scan was conducted from 50 to 200 °C with a heating rate of 5 °C/min at a frequency of 1 Hz and a strain of 0.05% in a double cantilever mode. The storage modulus and tan δ (the ratio of loss modulus to storage modulus) were obtained from DMA analysis, and the glass transition temperature (Tg) was gained from the peak value of tan δ.The micromorphology of BN nanofillers and BN/epoxy nanocomposites were investigated by field-emission scanning electron microscope  equipped with an energy-dispersive spectrum (EDS) component and transmission electron microscope . The samples for EDS were prepared by natural deposition BN nanofillers on a polished Ti substrate. The fracture surfaces of the epoxy nanocomposites were prepared by cryo fractured in liquid nitrogen. The optical photographs of BN nanofillers solution (2 mg·mLUsing raw BN (R-BN) powders as materials, three different kinds of BN nanofillers were prepared by ball-milling method, i.e., BM-BN, BM-KH550-BN, and BM@KH550-BN. As shown in 2 in KH550 can readily insert into the layered structure of BN with the assistance of mechanical force and weaken the atom interactions between electron acceptor B atom and neighboring planar N atom, resulting in the higher yield of BN nanosheets [To estimate the ratio of BN nanosheets (exfoliated BN) in different nanofillers, a centrifugal separation method was performed at 3000 rpm. Results indicate that the BM-BN and BM-KH550-BN exhibit a similar yield of BN nanosheets (~38%), indicating that the surface modification with KH550 does not change the amount of BN nanosheets. However, a yield of BN nanosheets as high as 73.3% is gained in BM@KH550-BN nanofillers A. This mnosheets . For theThe key element distribution of different BN nanofillers were detected by EDS (BN nanofillers deposited on polished Ti substrate). The element mapping images in −1 are indexed to the in-plane stretching vibration and out-of-plane bending vibration of B-N bond, respectively [−1 is hardly found in R-BN, but an obvious adsorption band is observed in ball-milling-treated BN nanofillers , which indicates that the ball-milling treatment enhances the degree of hydroxylation of R-BN [−1, which is indexed to the stretching vibration of the Si-O bond of KH550, emerges in BM-KH550-BN and BM@KH550-BN, implying that KH550 is successfully grafted onto the surface of BN nanofillers through the ball-milling process [In order to further investigate the chemical compositions of BN nanofillers, the FTIR spectra of BN nanofillers were recorded at room temperature. As shown in ectively ,33. It i of R-BN . It is n process .The thermal stability of BN nanofillers was analyzed by TGA. It can be seen from −1K−1, which is attributed to the fact that the highly cross-linked network structure of epoxy resin presents a low crystallinity and orderliness, which is not enough to make phonons propagate quickly [−1K−1 is obtained in the BM@KH550/epoxy nanocomposite, which is only 57.7% higher than neat epoxy. This can be understood by the fact that the small amount of thermally conductive BN nanofillers make it difficult to form an effective heat conduction path inside the epoxy resin. After the content of BN nanofillers is greater than 4%, the thermal conductivity of all the BN/epoxy nanocomposites enhances significantly with the increase in BN nanofillers, due to the gradual contact with each other among BN nanofillers. It is found that the thermal conductivity of R-BN/epoxy, BM-BN/epoxy, BM-KH550/epoxy, and BM@KH550/epoxy nanocomposites at 7 wt% increase to 0.307, 0.354, 0.391, and 0.431 W m−1K−1, respectively. When the content of BN nanofillers is further increased to 10 wt%, the enhancement of thermal conductivity of four epoxy nanocomposites presents relatively large differences. For R-BN/epoxy nanocomposites, the thermal conductivity is only enhanced to 0.325 W m−1K−1 from 0.307 W m−1K−1, which may be ascribed to the fact that the poor dispersion of R-BN nanofillers and the worse interfacial compatibility between R-BN nanofillers and epoxy matrix produces a lot of R-BN aggregation formations inside the R-BN/epoxy nanocomposite, hindering the conduction of heat. However, the BM-BN/epoxy, BM-KH550/epoxy, and BM@KH550/epoxy nanocomposites are determined to be 0.433, 0.507, and 0.615 W m−1K−1, which is increased by 108.2%, 143.8%, and 195.7%, respectively  among the four types of BN nanofillers , indicating the strongest reinforcing effect of BM@KH550 nanofillers on the epoxy matrix. In addition, the incorporation of fillers in polymer matrix can also affect the entanglement dynamics and mobility of the polymer chains around the fillers. Herein, the volume fraction of the constrained region can be quantitatively calculated by the tan δ value. The relationship between tan δ and energy loss fraction (W) of the polymer nanocomposites is given by the equation [0 and C0 are the energy loss fraction and volume fraction of the constrained region of neat epoxy, respectively [To explore the effect of different BN nanofillers on the dynamic thermomechanical properties of epoxy matrix, the effectiveness of BN nanofillers and constrained region of the epoxy nanocomposites were analyzed. The factor βectively . The Gg′equation :(2)W=π tectively . Equatio0 is taken as zero for neat epoxy, and the C value of epoxy nanocomposites are calculated by Equation (4). As listed in Herein, CAs is well known, the distribution of fillers in polymer matrix plays an important role in the thermal conductivity and thermomechanical properties of epoxy nanocomposites. Since the BM@KH550-BN/epoxy nanocomposite achieves the optimal thermal conductivity and thermomechanical properties in all the epoxy nanocomposites, it is necessary to investigate the distribution of BM@KH550-BN nanofillers at different loading content in epoxy matrix. Thus, the morphology of fracture surfaces of BM@KH550-BN/epoxy nanocomposites was analyzed. As shown in In summary, the KH550-modified BN (BM@KH550-BN) nanofillers were successfully prepared via a one-step ball-milling route, and a high proportion of BN nanosheets and excellent dispersion stability were confirmed in BM@KH550-BN nanofillers. As a result, the BM@KH550-BN nanofillers can enhance the thermal conductivity of epoxy nanocomposites significantly, with an enhancement of 195.7% at 10 wt%, compared to neat epoxy resin. In addition, the storage modulus and glass transition temperature (Tg) of BM@KH550-BN/epoxy nanocomposites also increase by 35.6% and 12.4 °C, respectively. The calculated results from the dynamical mechanical analysis show that the BM@KH550-BN nanofillers have the strongest reinforcing effect and the higher volume fraction of constrained region in all the epoxy nanocomposites. This is mainly attributed to the high ratio of BN nanosheets in BM@KH550-BN nanofillers and the good interfacial compatibility between nanofillers and matrix. This work develops a simple way to prepare high thermally conductive BN nanofillers, showing a good application prospect in the field of thermally conductive polymer nanocomposites.


High performance polymers with bio-based modifiers are promising materials in terms of applications and environmental impact. In this work, raw acacia honey was used as a bio-modifier for epoxy resin, as a rich source of functional groups. The addition of honey resulted in the formation of highly stable structures that were observed in scanning electron microscopy images as separate phases at the fracture surface, which were involved in the toughening of the resin. Structural changes were investigated, revealing the formation of a new aldehyde carbonyl group. Thermal analysis confirmed the formation of products that were stable up to 600 °C, with a glass transition temperature of 228 °C. An energy-controlled impact test was performed to compare the absorbed impact energy of bio-modified epoxy containing different amounts of honey with unmodified epoxy resin. The results showed that bio-modified epoxy resin with 3 wt% of acacia honey could withstand several impacts with full recovery, while unmodified epoxy resin broke at first impact. The absorbed energy at first impact was 2.5 times higher for bio-modified epoxy resin than it was for unmodified epoxy resin. In this manner, by using simple preparation and a raw material that is abundant in nature, a novel epoxy with high thermal and impact resistance was obtained, opening a path for further research in this field. Moisture can also induce corrosion in fiberglass, a frequently used reinforcement.Epoxy resins are widely used materials, due to their suitable properties such as a high Young’s modulus, chemical and thermal resistance, good corrosion resistance, and excellent insulation ,3,4,5,6.Recently, much attention was given to chemical modifications of epoxy in order to increase its thermal and mechanical properties. Meanwhile, growing environmental concerns, along with finite petrochemical resources, led to a focus on the development of composite materials with reinforcements from renewable resources . In ordeg) is very low, reducing the temperature range for application. Yu et al. prepared bio-based dimer acid diglycidyl ester for the toughening of DGEBA-based epoxy resin [g decreased, compared to the Tg with the unmodified epoxy. A similar trend was observed in soybean oil and saturated-fatty-acids-based modifiers prepared by Hu et al., except that the overall Tg values were significantly higher when compared to those in a previous study [Lignin is one of the main plant constituents, with a high content of functional groups that make it suitable for use as a raw material in the synthesis of bio-based epoxy, as a replacement for the diglycidyl ether of bisphenol A (DGEBA) . Howeverxy resin . With a us study . In ordeus study . With thus study . Furtherus study . They atHoney is known for heterogeneous structure, with reactive components that could be used in materials chemistry. Along with carbohydrates such as fructose and glucose, many other substances can be found in honey, depending on the plant source and geographical origin .Along with that, honey is a low cost, low moisture containing and abundant in nature raw material . In the 3) was used as the epoxy modifying agent.Diglycidyl ether of bisphenol A (DGEBA)-based epoxy resin and diethylenetriamine (DETA)-based hardener were purchased from R&G Faserverbundwerkstoffe GmbH, Composite Technology, Waldenbuch, Germany. Acacia honey, manufactured by ‘Mepolis’, Belgrade, Serbia  (TGA-DTG-DTA) , in the temperature range from room temperature to 600 °C, with a heat rate of 10 °C/min. The sample mass was 10 ± 0.5 mg. The measurements were performed in synthetic air (21 vol% O2 + 79 vol% N2).Morphological differences between E and EH were recorded with a Field Emission Scanning Electron Microscope—FESEM , surfaces were sputtered with gold. Structural changes with the addition of honey to epoxy resin were investigated using Fourier transform infrared—FTIR , 4000 and 400 cmtot and energy at maximum load-Efmax) values were calculated automatically from the load-time diagram. The diameter of the striker was 12.7 mm, with a hemispherical head; the set impact force was 10 kN. For samples E and EH1, impact velocity and depth were 0.05 m/s and 1 mm, respectively. A variation of impact depth and velocity . Absorbed energy  was divided into two regions to highlight structural differences between E and EH.Honey is mostly composed of water and simple sugars, such as fructose and glucose, although it contains proteins, vitamins, minerals, and many other substances in small amounts ,35. The products . Scheme products . In orde−1. However, in the spectrum of AH, this band was broader, indicating a higher concentration of hydroxyl groups that may originate from present moisture and carbohydrates. Aromatic –CH stretch was present in E and EH at 3063 cm−1 and 3032 cm−1, coming from phenolic groups in epoxy. Asymmetric –CH stretching can be seen in all the spectra around 2935 cm−1, as well as symmetric at 2870 cm−1.All spectra have broad bands from the H bonded –OH group in the region from 3350 to 3400 cm−1 and 1884 cm−1, originating from double-bonded carbon atoms. The most interesting structural change was observed by the appearance of a peak at 1721 cm−1, which comes from carbonyl groups that formed after the reaction of H and E. This peak was assumed to be from aldehyde C=O, which formed after the reaction of reducing sugars with amine [−1, a peak appeared that is related to the presence of moisture in H, which could overlap with 1° amide C=O, presumably from the proteins [E and EH3 showed small, broad bands around 1950 cmth amine . In the proteins ,40.−1, 1184 cm−1, 1107 cm−1 and 1033 cm−1, C–O stretching vibrations were observed in the spectra of E and EH3 [−1 and 1052 cm−1, C–O stretching from C–OH, characteristic for fructose and glucose carbohydrates. The absence of a band around 1185 cm−1 proved that our H sample did not contain sucrose [−1 [In the region from At 1245 cm and EH3 ,42,43. T sucrose . Out-of-rose [−1 ,45,46. Srose [−1 .In order to investigate the thermal stability of epoxy modified using acacia honey, simultaneous thermal analysis was performed in the air. Following the assumptions made by structural and morphological analyses, structures formed during processing should have resulted in bio-modified epoxy resin with high thermal stability. The curves obtained from TGA-DTG-DTA for the most representative sample, EH3, are presented in The second degradation stage was from 390 to 570 °C, where the largest weight loss of 25% occurred, with a strong DTG peak at 508 °C . In this5, T10, and T30 are presented in The char yield at 570 °C was 50%, which was significantly higher compared to the previous research regarding modified epoxies with improved thermal stability ,53. Thishri) (The heat resistance index (Thri)  was calc5 and T10 of EH3 were lower, but compared to their reported Tmax value of 368 °C, EH3 T50 of 570 °C was substantially higher [This value was comparable to epoxy reinforced with multi-walled carbon nanotubes, which revealed the potential of honey as a modifier. Compared to the highly stable DGEBA epoxy used by Mi et al., Ty higher .g) determined by DTA  is reached at the end of this phase. The energy absorbed by material at this moment is denoted as Efmax. The second phase starts when the crack forms, leading to a significant deterioration of mechanical properties until the breakage or rupture. Total absorbed energy (Etot) represents energy absorbed from the beginning of the controlled energy impact test until the load drops below zero, which is considered the end of the test. There are four common types of failure, corresponding to the material’s plastic deformation propensity. The first one is brittle failure, typical for ceramic materials and rigid polymer structures, such as cross-linked polymers that form 3D covalently bonded networks. This type of failure is described by no or very small plastic deformation with fast fracture, and low Etot value. Brittle-ductile fracture is the second type, characterized by a small plastic deformation before breakage. Materials that show ductile-brittle failure (third type) have the ability to plastically deform and absorb more energy during the impact. Extensive plastic deformations are distinctive feature of the fourth type of failure, corresponding to the large Etot value.The first phase involves the elastic response of the material and plastic deformation, which is characteristically low for fully cured epoxy resins. The maximum load (FEH3 was punctured eight times with different impact velocities and puncture depths. After the seventh impact, lower absorbed energies were measured as a consequence of the initiated damage from the previous impacts. The sample was left at room temperature for 24 h, after which EH3 returned to its original shape. On the other side, EH6 failed after the second impact, which was consistent with the indications made after the morphological analysis. fmax and Etot for all the samples are presented in fmax and Etot increased in EH3, to 2.22 J and 2.58 J, respectively. The brittle-ductile failure mode remained, in the absence of material failure. The shape of the load-time curve varied from impact to impact, from brittle-ductile to ductile. At the seventh impact, both absorbed energy values decreased compared to the sixth impact, which indicates the beginning of EH3 failure. Efmax decreased by 20%, Etot by 25%, but the sample did not break. However, after the sample was left for 24 h at room temperature, impact strength recovery occurred, which was demonstrated by the highest Efmax and Etot values observed at the final, eighth impact, where the 1 m/s impact velocity was set and the depth was 6 mm, leading to a puncture of EH3.On second impact, both EEH6 showed brittle failure during the second impact, as a consequence of the large crack that formed after the first impact. The absorbed energy increased to 3.50 J, but the sample was destroyed, which could be a consequence of an increased phase separation caused by unreacted components. This separation leads the a formation of large pores that could have weakened the sample after the crack initiation . Accordi−1, which presumably formed after the reaction of sugars in honey with DETA. Thermal analysis of the sample with 3 wt% of honey showed a high char yield of 50% at 570 °C, which is a consequence of DGEBA moiety participation in the reaction with honey, resulting in stable phenolic condensed structures. The heat resistance index was 173.8 °C, which is considered very high, as was the glass transition temperature of 228 °C. The influence of honey concentration in epoxy on impact resistance was investigated with a controlled energy impact test, and it was established that bio-modified epoxy with 3 wt% withstood several impacts without failure, absorbing the highest amount of energy during the final stroke, leading to the conclusion that it was the optimal amount for obtaining significantly toughened epoxy resin. In light of the presented results, honey proved to be an excellent bio-modifier, which also contributes to the expansion of investigation in the field of bio-based tougheners for polymeric materials.This study investigated the potential of honey as a toughener for DGEBA-based epoxy resin. After the addition of different amounts of honey to the DGEBA/DETA system, aldol condensation products formed, which were observed as a separate phase that was responsible for the toughening of the resin. Structural analysis revealed the formation of an aldehyde carbonyl group at 1721 cm


Compared with the monolithic joint, the epoxy composite SAC305 joints had a lower overall IMC growth rate during aging, closely related to the initial morphologies of the interfacial layers. The shear test results showed an apparent decrease in the shear forces of all the solder joints as the aging time increased. Nevertheless, because of the extra mechanical support provided by the epoxy layer, the epoxy composite joints demonstrated notably enhanced mechanical properties. After 1000 h aging treatment, the shear force of SAC305 joints containing 8 wt.% epoxy was 26.28 N, showing a 24.08% increase over the monolithic joint. Cu-Sn IMCs were detected on the shear fracture of the monolithic joint after 1000 h aging, indicating the fracture occurred near the interface and displayed a ductile/brittle mixed fracture. Concerning the epoxy composite joints, cracks were still initiated and extended within the solder bulk, demonstrating a noticeable enhancement in ductility due to the addition of epoxy.With the rapid iteration of microsystem integrated technology, the miniaturization of electronic devices requires packaging materials with higher reliability. In this work, the microstructure evolution and mechanical properties of novel epoxy composite SAC305 solder joints were studied after isothermal aging to evaluate the enhanced effect of epoxy addition. The thickness variation and morphological evolution of the interfacial layer were analyzed. The results showed that, as the aging time was prolonged, the Cu In recent decades, to meet the design requirements of continuous miniaturization and high performance for electronic devices, advanced electronic packaging technologies have been extensively developed and utilized in the electronic packaging industry ,2,3. Sn-6Sn5 and Cu3Sn, coarsen excessively under thermal loads, which may lead to the formation of structural defects and reliability degradation of the micro-joint [3Sn IMC layer forms and overgrows in the solid-state reaction, with the simultaneous emergence of Kirkendall voids [Meanwhile, with the arrival of the era of big data, 5G communication and AI technology have been rapidly developed . The denro-joint ,13. Durill voids . Wang etll voids  attribut2O3, SiC, CNTs, GNSs) to lead-free solder alloys is a feasible method [With the increased thermal and mechanical loads that interconnected joints withstand, solders are expected to have higher thermal reliability ,17. Manye method ,19,20. Ie method , who poie method .In the past few years, owing to the excellent wetting and high bonding strength, the development and performance evaluation of Sn-based solder materials containing epoxy have been research hotspots ,24,25. JThe monolithic SAC305 solder paste was fabricated using solder powders (25–45 μm diameter) and no-clean flux, which were supplied by Hoerson Electronics Technology Company Limited, Shenzhen, China. In this study, methyltetrahydrophthalic anhydride  served as the curing agent for E51 epoxy , and the ratio of E51 epoxy to the curing agent was 100:85. In addition, trace amounts of 2,4,6-Tris-(dimethylaminomethyl)phenol  were incorporated as an accelerator to expedite the curing process of the E51 epoxy. The monolithic SAC305 solder paste was mixed with the E51 epoxy curing system (including curing agent and accelerator) in proportion to prepare epoxy composite SAC305 solder pastes. The mixing process described above is performed using a solder paste mixer  with a rotation rate of 600 rpm, and the stirring time is 5 min. During the high-speed rotation process, the components of the composite solder paste were uniformized, and, simultaneously, the deaeration of the epoxy was accelerated. For the sake of brevity, the prepared SAC305 solder pastes containing 4 wt.%, 8 wt.% and 12 wt.% epoxy resin curing system are denoted by SAC305-4ER, SAC305-8ER and SAC305-12ER, respectively. The thermal behaviors of the monolithic SAC305 solder paste and epoxy composite SAC305 solder pastes were investigated by differential scanning calorimeter . The heating rate was set as 10 °C/min from 30 °C to 300 °C.Next, 0603 chip resistors were soldered to OSP-Cu pads on a printed circuit board (PCB) using the above SAC305 solder pastes through reflow soldering. The parameters of the 0603 chip resistors and the Cu pad are shown in 2O3 grinding paste, and acidic colloidal silica suspension was used for the final polishing. The top view of the interfacial IMCs was observed after removing the solder above the interface layer with thin nitric acid. The cross-sectional microstructure and top-view morphology of the IMC layer were analyzed by SEM  and the attached EDS, and then the thickness and grain size of the interfacial IMC were measured by image-J software (version: 1.54d).The macroscopic morphologies of the aged joints were observed to analyze the macro-appearance change in the cured epoxy. In order to investigate the cross-section microstructure, the specimens were cut by a gravity-fed precision sectioning machine . Subsequently, with the aid of a semi-automatic grinding and polishing machine , the specimens were initially polished by #400, #1200 and #2000 SiC sandpapers and 3 μm and 1 μm AlThe shear forces of the aged solder joints were measured using a micro-joint strength tester  according to Japanese Industrial Standard JIS Z3198-7 . The she6Sn5 IMC by EDS analysis.6Sn5 IMC. It should be noticed that the IMC layer thicknesses of all the as-soldered joints were similar because they had undergone the same reflow process. Nevertheless, the interfacial layer of the epoxy composite joint exhibited a relatively flat and smooth morphology relative to the monolithic joint. This phenomenon can also be revealed in the top-view microstructure of the interfacial IMCs of the as-soldered joints. As shown in 6Sn5 particles of the as-soldered monolithic joint, and the height difference between these particles was large. Nevertheless, the interfacial IMCs of the as-soldered epoxy composite joint gradually exhibited a homogeneous morphology with reduced grain size, as presented in As During the manufacturing process of soldering materials, organic acids and their anhydrides are commonly used as activators in the flux to enhance the interaction between the solder and the substrate ,34. The 6Sn5 IMC and Cu substrates. With regard to the EDS elemental analysis . The following section will discuss and analyze the variation in thickness and the coarsened behaviors of the interfacial layer.During the subsequent aging, the interfacial IMC layer gradually thickened and became flatter for a given joint type, accompanied by the emergence of a new IMC layer between the Cutx is the thickness of the interfacial IMC layer after t h aging, x0 is the primary IMC thickness before aging and D is the diffusion coefficient. Based on the above formula, there exists a linear relationship between tx and the square root of t. tx) and the square root of the aging time (t), and the fitting data are listed in It is widely recognized that the atomic diffusion mechanism dominates IMC growth at the interface of the solder bulk/Cu pad during aging, which can be expressed as ,39:xt=x06Sn5 IMC, as described below [During the reflow process, the primary chemical reaction conducted between the melted solder alloy and Cu pad was the nucleation and growth of Cued below :6Cu+5Sn 6Sn5 gradually thickened because of the continuous diffusion of Cu and Sn atoms. It has previously been mentioned that, at room temperature or during solid-state thermal aging, Cu can move into Sn and Cu6Sn5 IMC by interstitial diffusion, which is easier than the movement of Sn to Cu, dominated by lattice diffusion [In the subsequent solid-state aging, the Cuiffusion . As illuiffusion . The traiffusion  investig3Sn compound took place between the Cu6Sn5 IMC layer and the Cu pad, resulting from the gradual consumption of Cu6Sn5 IMC, as depicted below [As the aging time increased, the formation of the Cued below :Cu6Sn5+9With the continuous atomic diffusion during aging, the IMC layers of all the joints thickened, and the top-view images indicated that the IMC grain sizes increased, accompanied by the planarization process.Long-term aging will lead to the reliability degradation of tin-based solder joints because of the accelerated atomic diffusion and stress concentration. The shear test is the most direct means of assessing joint reliability. The decrement in the mechanical property of tin-based solder joints can be mainly ascribed to the coarsening of the solder bulk and the thickening of the brittle interfacial layer . SignifiTo further determine the impact of epoxy addition on the shear performance of the solder joint, the fracture morphology was observed after the shear test. However, as presented in 3Sn layer emerged between the Cu6Sn5 layer and the Cu pad. However, the growth rate of the interfacial IMC layer of the epoxy composite joint was lower than that of the monolithic joint.After high-temperature storage for 1000 h, the macroscopic images revealed the epoxy layer on the joint surface remained intact without any noticeable defects. As the aging time was prolonged, the thicknesses and grain sizes of the interfacial IMC layer of all the joints increased, and the Cu−17 m2/s to 1.00 × 10−17 m2/s, 0.63 × 10−17 m2/s and 0.71 × 10−17 m2/s, respectively.The addition of epoxy resulted in a more uniform morphology of interfacial IMCs in the as-soldered joints, leading to higher thermal stability in the epoxy composite solder joints. With the addition of 4 wt.%, 8 wt.% and 12 wt.% epoxy, the growth coefficients of the IMC layer gradually decreased from 1.74 × 10The shear forces of the epoxy composite joints were remarkably increased due to their thinner IMC layers and the extra bonding area created by the epoxy layer. After aging for 1000 h, the fracture location of the monolithic joint transformed from the solder bulk to the interface of the solder/IMC layer, which presented a ductile/brittle mixed fracture. However, the fracture mode of the epoxy composite joint remained almost unchanged after long-term aging, showing its better ductility.In this study, an isothermal aging test was carried out to assess the thermal reliability of epoxy composite SAC305 solder joints. The impact of the epoxy addition on the interfacial growth behaviors, shear properties and fracture morphologies of the joints was analyzed. The following conclusions can be drawn:


In recent decades, the use of thermoset epoxy resins (ER) has spread to countless applications due to their mechanical properties, heat resistance and stability. However, these ERs are neither biodegradable nor recyclable due to their permanent crosslinked networks and usually, they are synthesized from fossil and toxic precursors. Therefore, reducing its consumption is of vital importance to the environment. On the one hand, the solution to the recyclability problems of epoxy resins can be achieved through the use of vitrimers, which have thermoset properties and can be recycled as thermoplastic materials. On the other hand, vitrimers can be made from natural sources, reducing their toxicity. In this work, a sustainable epoxy vitrimer has been efficiently synthesized, VESOV, by curing epoxidized soybean oil (ESO) with a new vanillin-derived Schiff base (VSB) dynamic hardener, aliphatic diamine  and using 1,2-dimethylimidazole (DMI) as an accelerator. Likewise, using the same synthesized VSB agent, a commercial epoxy resin has also been cured and characterized as ESO. Finally, different percentages  of the same ER have been included in the formulation of VESOV, demonstrating that only including 30 wt% of ER in the formulation is able to improve the thermo-mechanical properties, maintaining the VESOV’s inherent reprocessability or recyclability. In short, this is the first approach to achieve a new material that can be postulated in the future as a replacement for current commercial epoxy resins, although it still requires a minimum percentage of RE in the formulation, it makes it possible to recycle the material while maintaining good mechanical properties. In recent years, special attention has been paid to the use of epoxy resins (ER). This type of thermoset polymer has distinguished properties, such as thermal stability, mechanical strength, creep resistance, electrical insulation, and chemical resistance ,4,5,6,7.Nevertheless, most of the current epoxy thermosets (~90%) are prepared from non-renewable diglycidyl ether of bisphenol A (DGEBA) and cannot be reprocessed or recycled due to their permanent crosslinking, which causes significant waste and environmental problems after their service lifetime ,12,13. Ig) [Therefore, recently, more attention has been paid to designing sustainable epoxy thermoset resins from diverse renewable resources, such as epoxidized vegetable oils , cardanog) ,22.To address these issues, new studies to develop new epoxy resins that contain the remarkable properties of thermosets, as well as the intrinsic capacity of thermoplastics to be recycled after their useful life, are needed. One of the possible solutions is the development of covalent adaptable networks (CANs).The so-called CANs are polymeric materials with permanent crosslinks, which can reversibly transform into dynamic crosslinks, allowing their chains to flow  when they are induced by an external stimulus, such as temperature ,24, expoIn 2011, Leibler et al. reported  a new clv) [v is chosen by agreement as the temperature at which the viscosity reaches 1012 Pa∙s [v, vitrimers behave as conventional thermosets, and above Tv, they can undergo creeping and relaxing stresses. The control of this temperature is essential since the exchange of covalent bonds and permanent crosslinking allows or does not allow thermal recycling [The viscoelastic behavior of vitrimers changes with the topology freezing temperature (Tv) . The Tv 012 Pa∙s . Below Tecycling ,44,45. Tg epoxy vitrimers combined with superior mechanical strength and modulus [The developed vitrimers so far have been overviewed according to the nature of the dynamic exchange reaction. The most common dynamic interactions used in the design of vitrimers have been carboxylate transesterification , transam modulus ,52,53. I modulus . TherefoTaking into account all the premises described, in this work, a biovitrimer is developed from components obtained from natural resources, such as epoxidized soybean oil (ESO) and VAN. ESO is used as a bio-based monomer and a vanillin derivative as a new Schiff base to act as a biobased hardener. First, the Schiff base is prepared using VAN and aliphatic diamine . Second, ESO and the new Schiff base are combined to form the vitrimer. However, numerous studies have shown the susceptibility of vitrimers to creep substantially under use conditions ,56,57. F−1) were purchased from Sigma Aldrich . Methanol  was obtained from PANREAC . Epoxidized soybean oil (ESO) EPOVINSTAB H-800-D was kindly supplied by Hebron S.A. . All the chemicals were used as received.Vanillin , 1,4-butanediamine , 1,2-dimethylimidazole  and commercial epoxy resin (ER) poly(bisphenol A-co-epichlorohydrin) glycidyl end-capped (Mn~355 g molThe vanillin-derived Schiff base (VSB) curing agent was synthesized by dissolving 10.0 g (66 mmol) of vanillin in 100 mL of methanol and mixed in a 500 mL single-necked round-bottomed flask with 3.3 mL (33 mmol) of 1,4-butandiamine. A yellow powdered product (VSB) was obtained a after sThe VSB-cured ESO biovitrimer (VESOV) was synthesized by a two-stage procedure pre- and post-curing. To achieve the pre-curing stage, predetermined amounts of VSB and ESO were added to the reaction using an equivalent phenolic/epoxy hydroxyl ratio (simplified as X). Previous works performed by Zhao et al.  and ZengFor the synthesis of VESOV+ER, the same procedure was used, adding the epoxy resin at the same time as the ESO. Thus, it was decided to add progressive amounts by weight of epoxy resin  to determine the influence of the addition of epoxy resin to the VESOV. Additionally, to investigate the reaction between VSB+ER, the same procedure as ESO was followed, adding ER to the VSB. Therefore, the mechanical and thermal properties of five samples were studied: VESOV, VESOV+ER (30 wt% of ER), VESOV+ER (50 wt%), VESOV+ER (70 wt%) and VSB+ER.−1 were recorded by a Nicolet Nexus spectrophotometer , where the samples were measured within KBr pellets. The resolution and scanning number were 4 cm−1 and 32 times, respectively. The data were analyzed using OMNIC 8.2 software.Fourier transform infrared (FTIR) spectra with wavelengths from 4000 to 400 cm1H-NMR) spectra were recorded on a Bruker AV-600 (600 MHz) spectrometer  using deuterated chloroform (CDCl3) as the solvent.Proton nuclear magnetic resonance  equipped with STAR© v14.0 software. The samples (~10 mg) were placed in 100 μL aluminum crucibles. Samples were heated from −10 °C to 250 °C, in the case of the VSB, and from −10 °C to 150 °C for the vitrimers. A scanning rate of 10 °C·min−1 under a nitrogen atmosphere with a flow rate of 20 mL·min−1.The melting temperature of VSB and the glass transition temperature of the vitrimers were measured by differential scanning calorimeter (DSC) with a DSC METTLER TOLEDO 822−1) with a temperature range of 25–800 °C and a heating rate of 10 °C·min−1 by a SHIMADZU DTG-60 thermal gravimetric analyzer . The statistic heat-resistant index temperature (Ts) is a characteristic of the thermal stability of the cured resin [5% and T30% are the temperatures at, respectively, 5% and 30% weight loss. T5% was considered the onset decomposition temperature (To) of the sample.The thermal stability of the samples (~10 mg) was measured by thermal gravimetric analysis (TGA) under a nitrogen atmosphere , loss modulus (E″) and loss factors (tan δ) values were collected at 3 °C·min−1 heating rate from −10 to 150 °C, displacement of 20 µm, and 1, 3 and 10 Hz frequencies. Rectangular-shaped testing bars with a width of 5.0 mm, length of 10.0 mm and thickness of 0.5 mm were prepared. The glass transition was assigned at the maximum of the loss factor (tan δ = E″/E′).Dynamic mechanical analysis (DMA) was carried out in the tensile mode by a DMA1-METTLER TOLEDO instrument  equipped with STARReprocessing tests were performed on the compression molding machine . The films were cut into small pieces with scissors, placed into the 10 cm × 10 cm × 1.0 mm stainless steel mold, and reprocessed at 150 °C for 60 min at 10 bar. After cooling to room temperature, the reprocessed films were obtained, and their thermo-mechanical properties were measured.Epoxy thermosets exhibit tremendous thermo-mechanical properties; however, they lack the capacity to be reprocessed after their use. The main objective of this work is to obtain a substitute for epoxy resins that can be considered biobased. In this regard, it must be taken into account that to consider a material as biobased, a minimum of 50% of the compounds incorporated into its formulation must be obtained from natural resources. For this, first, the Schiff base is synthesized using VAN and aliphatic diamine . Then, a sustainable epoxy vitrimer derived from vegetable oil ESO is prepared, and finally, to improve the thermo-mechanical properties of the reprocessable vitrimer, a small amount of commercial epoxy resin (ER) is added.1H-NMR. −1) of the VAN and the broad stretching of N-H (between 3400 and 3250 cm−1) of BDA is not observed in the VSB FTIR spectrum. Instead, a new characteristic peak appears at 1655 cm−1 for VSB, attributing to the formed Schiff base unit . Moreover, 1H-NMR easily  show the same trend as To (or T5%) values. The results demonstrate that samples with low epoxy resin (ER) content exhibit higher thermal stability (VESOV has the highest), whereas increasing the ER content (VESOV+ER) decreases the thermal stability. The reason for this behavior could be associated with the higher amount of VSB in the network, involving a higher content of imine bonds. Moreover, the higher the oxirane ring content, the more ester and hydroxyl groups are created through the curing. These functions can also promote the thermal scissions of the networks [From networks .g), which usually acts as the upper limit use temperature for thermosetting materials, is a major parameter [g-onset (simplified as Tg) between VESOV, VESOV+ER (different percentages) and VSB+ER.The glass transition temperature  was not enough to obtain a fully cured vitrimer. In g of the different samples is summarized (Tg-onset).In g values rise significantly; that is, higher stiffness is achieved by making the fluidity of the chains more difficult. Therefore, the addition of a small amount of epoxy resin helps VESOV to improve its thermal properties. Indeed, VESOV has a Tg equal to 28.7 °C, while the addition of only 30 wt% of ER increases the Tg to 48.2 °C. However, by continuing to add more percentage in weight in ER (50 and 70 wt%), the increase that occurs in Tg is not as significant . That is, a larger increase in the added proportion of ER did not provide significantly higher Tg.As can be noticed in g of the samples was determined via DMA. g of each sample) versus temperature. In addition, Further, the TAs in the DSC, it is observed that while increasing the amount of epoxy resin, the glass transition temperature of the sample increases progressively. On the other hand, in In conclusion, analyzing the results obtained so far, it can be said that adding a small amount of epoxy resin (30 wt%) considerably improves the thermo-mechanical properties of the VESOV vitrimer. Finally, the reprocessability of these vitrimers was studied.The dynamic character of the Schiff base exchanges improves the ability of the samples to be reprocessed. The reprocessing is performed as explained before: The samples were cut into small pieces with scissors, placed into a steel mold and reprocessed at 150 °C for 60 min at 10 bar. These reprocessed samples are shown in Yet, it is necessary to verify that this reprocessing does not diminish the good thermo-mechanical properties obtained for the original samples. For this, the characterizations via DSC and DMA of the different reprocessed samples were accomplished. Moreover, a comparison between the original and remolded samples is performed to evaluate how many times samples can be reprocessed without losing their thermo-mechanical properties.g, showing that they are totally cured  and contains elements of a thermoplastic (good reprocessability), with this last property not attributable to conventional epoxy resins.In conclusion, it has been possible to verify that 1,4-butandiamine is a suitable reagent to synthesize a vanillin-derived Schiff base (VSB) that can be used as a curing agent in the development of a new vitrimer from epoxidized soybean oil (VESOV). Furthermore, the inclusion of a commercial epoxy resin to the VESOV helped to improve its mechanical and thermal properties, observing by DSC and DMA techniques that when the percentage of epoxy resin increases, the TIn short, this new dynamic hardener based on vanillin and 1,4-butandiamine obtained good properties as expected; a sustainable vitrimer was synthesize based only on epoxidized vegetable oil. The first approach to this objective has been made by developing a new material with remarkable features by adding a small amount of commercial epoxy resin (30 wt%), so the material can be considered biobased with good mechanical properties and the possibility of recycling. Therefore, this material can be postulated in the future, with slight improvements, to be a replacement for current commercial epoxy resins.


This study aims to reveal the effects of flexible chain lengths on rosin-based epoxy resin’s properties. Two rosin-based epoxy monomers with varying chain lengths were synthesized: AR-EGDE (derived from ethylene glycol diglycidyl ether-modified acrylic acid rosin) and ARE (derived from acrylic acid rosin and epichlorohydrin). Diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA) with different flexible chain lengths were used as curing agents. The adhesion, impact, pencil hardness, flexibility, water and heat resistance, and weatherability of the epoxy resins were systematically examined. It was found that when the flexible chains of rosin-based epoxy monomers were grown from ARE to AR-EGDE, due to the increased space of rosin-based fused rings, the toughness, adhesion, and water resistance of the rosin-based epoxy resins were enhanced, while the pencil hardness and heat resistance decreased. However, when the flexible chains of curing agents were lengthened, the resin’s performance did not change significantly because the space between the fused rings changed little. This indicates that the properties of the rosin-based resins can only be altered when the introduced flexible chain increases the space between the fused rings. The study also compared rosin-based resins to E20, a commercial petroleum-based epoxy of the bisphenol A type. The rosin-based resins demonstrated superior adhesion, water resistance, and weatherability compared to the E20 resins, indicating the remarkable durability of the rosin-based resin. A number of studies have demonstrated that humans could overcome the resource problem by utilizing just seven percent of the biomass that exists [Epoxy resins are three-dimensional network structure polymers formed by the reaction of epoxy monomer and a curing agent; thus, the properties of epoxy resins depend on the structure of the epoxy monomer and curing agent . Consequt exists .Rosin, a renewable resource that is abundantly available, is produced from pine and conifer trees, with a yearly global yield of approximately 1.27 million tons . It is aHowever, to our knowledge, the effects of epoxy monomers and curing agents with different flexible chain lengths on the properties of rosin-based epoxy resins have not been studied systematically, nor have the effects of flexible chains with different structures been compared. In this study, rosin-based epoxy monomers with various flexible chains were obtained: ARE, a diglycidyl ester derived from acrylic acid rosin and epichlorohydrin that lacked flexible chains, and AR-EGDE, an ethylene glycol diglycidyl ether-modified acrylic acid rosin with flexible chains. Diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA) with different chain lengths were used concurrently to cure the aforementioned epoxy resins. The impacts of epoxy monomers and curing agents with various flexible chains on the adhesion, impact, pencil hardness, flexibility, water and heat resistance, and weatherability of rosin-based epoxy resins were studied. In the meantime, the effects of two distinct flexible chains on the properties of rosin-based epoxy resin were compared, and the structure of the flexible chain required to increase its toughness was determined. In addition, commercial epoxy resin was utilized for comparison purposes. According to the results, the bio-based resin with superior adhesion outperforms the commercial one (DGEBA).−1). Ethylene glycol diglycidyl ether (EGDE) with an epoxy value of 0.73 mol/100 g was acquired from Wuhan Yuancheng Create Technology Co.  E-20  was purchased from Wuxi Resin Factory of Blue Star New Chemical Material Co., Ltd. . From Sinopharm Group Chemical Reagent Co., Ltd. , diethylenetriamine (DETA) and triethylenetetramine (TETA) were purchased. Epichlorohydrin (EC), ethanol (EtOH), acetone, potassium hydroxide (KOH), and triethylamine (Et3N) were of chemically pure quality and were utilized directly.Wuzhou Sun Shine Forestry & Chemicals Co., Ltd.  provided the acrylic acid rosin (ARA)  were added to a 500 mL four-neck round-bottom flask equipped with a reflux condenser, a mechanical stirrer, a thermometer, and an N2 inlet. The temperature of the system was raised to 110 °C and maintained until the acid number declined below 0.5 mg KOH/g. After cooling to 70 °C, 0.42 mol of solid NaOH (17.00 g) was added, and the temperature was maintained for 3 h. After the reaction, the precipitate was filtered out, and the filtrate was neutralized with water. After separation, the organic layer was evaporated at approximately 50 °C to recover excess epichlorohydrin, resulting in a yellow, transparent, viscous liquid.ARA , EC , and Et3N (0.02% of the ARA mass) was added as a catalyst once the acrylic rosin had been completely dissolved. After reacting at 130 °C for 1 h, an additional 50.00 g of ARA (0.2117 mol carboxyl group) was added, and the reaction temperature was maintained until the acid value fell below 0.5 mg KOH/g, at which point the reaction was terminated. The product was a yellow, viscous, transparent liquid.EGDE  and ARA  were added to a 500 mL four-necked flask equipped with a reflux condenser, agitator, thermometer, and nitrogen tubing. EtStoichiometrically, the epoxy monomers and curing agents were blended. Then, certain amounts of mixed solvents (xylene and butanol) were added to the above blends. The ratio of xylene to butanol by mass was 70:30. The method yielded a mixture that was aged for 30 min before being coated on 120 mm × 50 mm tinplates. This was carried out in accordance with GB/T 1727-2021 . For eacUsing the KBr method, an RFX-65A  FTIR instrument was used to acquire the infrared spectra of the prepared epoxy monomers. The hardness was assessed in accordance with GB/T 6739-2006 . Using the paint film scriber A2012058 (Elcometer), the adhesion was evaluated using a cross-cut test per GB/T 9286-2021 . The impact resistance was evaluated in accordance with GB/T 1732-2020 , using aThe flexibility was determined via GB/T 1731-2020 . The heat resistance was measured as per GB/T 1735-2009 . The tinThe tinplates were placed in the sun for 60 days to test weatherability. For 49 days, painted tinplates were immersed vertically in 3000 mL water-filled glass beakers to study the water resistance behavior of the films. Regular inspections of the tinplates were conducted to assess the level of attack on the paint coatings and the substrate. At various intervals, the tinplates were removed, rinsed with water, and visually inspected for film integrity, overall appearance, and film failure.2 − W1)/W1 × 100%, where W2 and W1 are the weights after and before absorption, respectively.The swelling behavior was investigated by immersing strip-shaped samples in water at room temperature. The percent change in mass was obtained using the following equation: percent change in mass =  resin were also found to be unaffected by the flexible chain length of its curing agent. The pencil hardness of the E20 coatings was 3H, which was equivalent to that of the ARE coatings. This indicates that the rosin-based fused ring structure is comparable to the rigidity of the benzene ring of the bisphenol A type. The results of the E20 coating tests for flexibility and impact resistance were superior to those of ARE, indicating that the brittleness of rosin-based fused rings is greater than that of benzene rings. However, the cross-test grades of the E20 coatings were 5, which were not only lower than the AR-EGDE coatings with flexible chains, but also lower than that of the ARE coating, which indicates that the rosin-based fused ring has better adhesion than the benzene ring of bisphenol A epoxy resin. There was no whitening phenomenon observed in E20 epoxy coatings, but there was slight rusting. The water resistance of the E20 epoxy coatings was even worse than that of the AR-EGDE from a rust perspective. In most cases, a material’s low water resistance results from its high water absorption. Nevertheless, the water absorption rates of the E20 coatings were significantly lower than those of AR-EGDE coatings . This suT5%) and the remaining solid residue at 700 °C were determined. From the DTG curve, the maximal weight loss rate temperatures (Tmax) were determined. The information is shown in Tmax of rosin-based epoxy resins has two distinct peaks, and their second peak height (approximately 420 °C) is nearly identical. It suggests that the first peaks correspond to the breakdown of the flexible chain segment, while the second peaks correspond to the breakdown of the rosin-based fused ring. The first Tmax of the E20 resins exhibits a lower value compared to rosin-based epoxy resins, accompanied by a notably weaker peak intensity. Consequently, the T5% of the E20 resins is lower than that of rosin-based epoxy resin. On the other hand, the second Tmax which corresponds to the degradation of the benzene ring, is higher in the E20 resins compared to rosin-based epoxy resin. This demonstrates that, in comparison to rosin-based epoxy resin, the thermal degradation of bisphenol A epoxy resin is weaker at low temperatures and stronger at high temperatures. In addition, TGA was used to evaluate the thermal degradation of the material. When the curing agent remained the same, the adhesion, flexibility, and impact resistance of the rosin-based epoxy resins improved as the flexible chain of the epoxy monomer increased from ARE to AR-EGDE. This indicates that the introduction of flexible chains decreased the brittleness of rosin-based fused rings and enhanced the toughness of rosin-based epoxy resins. When the epoxy monomer remained unchanged and the curing agent’s flexible chain grew from DETA to TETA, the performance of the resin, including its flexibility and impact resistance, remained relatively constant. This demonstrates that although the flexible chain of the curing agent was lengthened, the brittleness of the resin was not significantly reduced, so the toughness was not enhanced.To investigate the reasons, structural fragments of three rosin-based epoxy resins were illustrated see . By compTo reduce the negative effects of the brittleness of rosin-based epoxy resin and increase its toughness, it is not necessary to simply increase the flexible chains of the epoxy monomer and curing agent; rather, the structure of the cured resin must be designed so that the rigid rosin-based fused ring is separated by an appropriate distance. The adhesion, flexibility, impact resistance, water resistance, and heat resistance of rosin-based epoxy resins containing epoxy monomers and curing agents with different flexible chains were compared. When the curing agent was left unchanged and the length of the flexible chain of the epoxy monomer was increased (from ARE to AR-EGDE), the toughness of the rosin-based epoxy resins increased, resulting in an increase in adhesion and a decrease in heat resistance. When the epoxy monomer was left unchanged and the length of the flexible chain of the curing agent was increased (from DETA to TETA), the performance of the rosin-based epoxy resin was not significantly altered. Analyzing the structure of rosin-based epoxy resin revealed that changing the epoxy monomer from ARE to AR-EGDE with a longer flexible chain increased the spacing between the rosin-based fused ring, thereby decreasing the brittleness and altering its properties. However, changing the curing agent from DETA to TETA, which has a longer flexible chain, had minimal effects on brittleness and resin performance. Therefore, when introducing a flexible chain to improve the brittleness of rosin-based resins, it is necessary to increase the spacing between the fused rings in the resins. In addition, rosin-based epoxy resin outperformed bisphenol A epoxy resin E20 in adhesion and weather resistance, allowing it to have a broader range of applications.