Mechanical characteristics of tire/clay modified epoxy used in fabrication of medical prostheses and artificial human parts
Epoxy is used in many dental and medical applications such as manufacturing prostheses. This polymer is not toxic and is a good candidate for easily forming of artificial hand, leg, etc. In recent years, the recycled waste tire has been concerned as inexpensive modifier for improving the toughness characteristics of many thermoset resins such as epoxy. Herein, the influence of addition of nanoclay on mechanical characteristics of waste tire-modified epoxy was investigated. Mechanical properties i.e. compressive and flexural characteristics, fracture toughness and impact strength of the samples were investigated. The fracture surfaces of the specimens were examined using scanning electron microscope (SEM). Moreover the glass transition temperature (T ) of the samples were measured. Results reveal that nanoclay can improve the g mechanical characteristics of waste tire-modified epoxies.
Epoxy/GO nanocomposite adhesives reinforced with waste blends of PET/GTR: Evaluation of mechanical properties
Abstract In this work, the effects of the graphene oxide (GO) content and composition of waste blends of poly(ethylene terephthalate) (W-PET) and ground rubber tire (GRT) on the mechanical properties and lap-shear strength of epoxy adhesives have been discussed. Adhesives based on diglycidyl ether of bis-phenol A (DGEBA) were developed in which extrusion-blended waste blends of W-PET/GRT were incorporated at variable composition (80/20, 50/50, 20/80) together with maleic-anhydride grafted SEBS (SEBS-g-MAH) as a binding agent. Dumbbell-shaped samples and adhesively bonded steel-(epoxy/carbon fiber composite) joints were used to evaluate tension properties of adhesives. The results indicated that addition of 10 phr of SEBS-g-MAH compatibilized 20/80 w/w blend of W-PET/GTR with 0.3 phr GO to epoxy formulation resulted in an increase of modulus, tensile strength and toughness to 33.2, 247.9, and 551.2%, respectively. The stiffness of GO together with its proper adhesion to epoxy/(W-PET/GTR) was responsible for this behavior. The overall shear strength of the composite-metal samples adhered by developed epoxy formulation was increased by 101% compared to the neat epoxy matrix.
Study on starch-graft-acrylamide/mineral powder superabsorbent composite
Abstract A novel starch- graft -acrylamide/mineral powder superabsorbent composite with water absorbency about 4000 times is synthesized by graft-copolymerization reaction among acrylamide, potato starch and mineral ultrafinepowder, followed by hydrolysis with sodium hydroxide. It is found that the composite doped with kaolinite powder possess higher water absorbency than those doped with bentonite or sercite powder, since the kaolinite powder can moderately disperse in the water and cross-link with acrylamide and starch. By controlling the amount of NaOH and reaction time during saponification process, the hydrophilic groups on the composite can be adjusted, it is found that the collaborative absorbent effect of −CONH 2 , −COONa and −COOH groups is superior to that of single −CONH 2 , −COONa or −COOH group. By the IR characterization, the polymerization reaction mechanism and structure of the composite is supposed, the mineral ultrafinepowder as a cross-linking point play an important role in the formation of network structure of the superabsorbent composite.