Thermal and mechanical properties of polypropylene/wood‐flour composites

Abstract

In this research, polypropylene/wood-flour composites (WPCs) were blended with different contents of wood and/or maleated polypropylene (MAPP) and clay. We found that the addition of MAPP or clay in the formulation greatly improved the dispersion of the wood fibers in the composite; this suggested that MAPP or clay may have played the role of an adhesion promoter in the WPCs. The results obtained with clay indicate that it also acted as a flame retardant. The thermal tests carried out with the produced samples showed an increased crystallization temperature (T c ), crystallinity, and melting temperature (T m ) with wood loading. The increase of the two former parameters was explained by the incorporation of wood flour, which played the role of nucleating agent and induced the crystallization of the matrix polymer. On the other hand, the T m increase was ascribed to the insulating properties of wood, which hindered the movement of heat conduction. The effects of UV irradiation on T m and T c were also examined. T c increased with UV exposure time; this implied that UV degradation generated short chains with low molecular weight that could move easily in the bulk of the sample and, thus, catalyze early crystallization. The flexural strength and modulus increased with increasing wood-flour content. In contrast, the impact strength and tensile strength and strain decreased with increasing wood-flour content. All of these changes were related to the level of dispersion of the wood flour in the polymeric matrix.

Mechanical and thermal properties of oil palm wood sawdust reinforced post-consumer polyethylene composites

“…3, it can be observed that when the OWS concentration was increased, the matrix coverage was insufficient and many voids appeared leading to weak interfacial adhesion. Any initial separation spreads easily 12 , and thus reduces the mechanical strength of the composites. In addition, the many voids or cavities in the structure of oil palm wood are another significant factor in the reduction of mechanical properties.…”

Combined effect of water uptake and temperature on wood polymer composites

“…A comprehensive analysis of various factors influencing the performance of WPCs has been recently reported by Olakanmi and Strydom . In addition, several studies have correlated the effects of moisture, or water uptake, to the reduction of mechanical properties, that is, bending, tension, impact, and creep . Properties decay has been attributed to the degradation of the natural filler as a result of long‐term water exposition, development of internal stress due to filler swelling and matrix–reinforcement interface failure .…”

Selected Aspects of Wear and Surface Properties of Polypropylene Based Wood-Polymer Composites

“…Main goal of this investigation to make conclusions about the effects of the roughness of the abrasive as well as the amount of abrasion cycles on the wear resistance and surface properties of WPC made from PP and 40 wt.% wood flour. Surface wear dynamics and change in hydrophilic/hydrophobic behaviour are important for floor and some other heavy duty applications [4][5][6][7]. POLYMER COMPOSITES.…”