Cyanoethylation of several fiber materials and their utilization as adhesive in wood-based panels
This study examines the cyanoethylation and thermoplasticity of several cyanoethylated fiber materials. Cyanoethylated pulps with a degree of substitution of 1.43 have the lowest Vicat softening point. Cyanoethylated poplar with a weight gain of 18.2 % has the lowest melting temperature. Instead of traditional adhesives, cyanoethylated materials can be used to produce wood-based panels because of their good thermoplasticity. Plywood bonded with cyanoethylated pulp has a bonding strength of 2.06 MPa and an average wood failure of 62.7 %. Wheat straw particle board containing 40 % cyanoethylated pulp has an internal bonding strength of 0.49 MPa, a modulus of rupture (MOR) of 33 MPa, and a density between 0.5 and 0.6 g cm−3. Fiberboard containing 40 % cyanoethylated pulp has an internal bonding strength of 0.53 MPa, MOR of 38 MPa, modulus of elasticity of 4,200 MPa, and a density between 0.7 and 0.8 g cm−3. Its swelling in thickness is 41 %.
Wood Waste Turned Into Value Added Products: Thermal Plasticization by Benzylation Process
Sawdust is usually considered as waste in wood-using industries. These materials can be converted into value added thermoplastics by means of benzylation. Products can be utilized in different applications where plastics are used. Thermoplasticization process was carried out with benzyl chloride under different alkaline conditions, 15, 25 and 35 %, respectively. Alkali ions and concentration affect the substitution reaction. Tailored material structure was remarkably changed. In order to detect changes, crystallinity index of the materials and thermal properties were analyzed. In FTIR spectra, the peaks appeared at 698 cm-1 and 740 cm-1, which indicates the aromatic C-C angular deformation. Multiple peak appears at 3030 cm-1, which indicates benzylation of the materials. The peak increase can be observed at 1596 cm-1 due to the aromatic deformation. Benzyl groups attached to hydroxyl to form ether groups increase the peak intensity. As a result of that, hydrogen bond energy changes and crystallinity of the materials is reduced. This substitution of functional groups changes the decomposition temperature of modifi ed materials. It reduces the decomposition temperature to between 330 and 350 oC. Thermogravimetric analysis revealed that modifi ed products were characterized by poorer thermal stability compared to raw materials.
Surface roughness monitoring by singular spectrum analysis of vibration signals
Abstract This study assessed two methods for enhanced surface roughness (Ra) monitoring based on the application of singular spectrum analysis (SSA) to vibrations signals generated in workpiece-cutting tool interaction in CNC finish turning operations i.e., the individual analysis of principal components (I-SSA), and the grouping analysis of correlated principal components (G-SSA). Singular spectrum analysis is a non-parametric technique of time series analysis that decomposes a signal into a set of independent additive time series referred to as principal components. A number of experiments with different cutting conditions were performed to assess surface roughness monitoring using both of these methods. The results show that singular spectrum analysis of vibration signal processing discriminated the frequency ranges effective for predicting surface roughness. Grouping analysis of correlated principal components (G-SSA) proved to be the most efficient method for monitoring surface roughness, with optimum prediction and reliability results at a lower analytical-computational cost. Finally, the results show that singular spectrum analysis is an ideal method for analyzing vibration signals applied to the on-line monitoring of surface roughness.