Wood Flour and Polypropylene or High Density Polyethylene Composites: Influence of Maleated Polypropylene Concentration and Extrusion Temperature on Properties

Abstract

The effects of the concentration of a maleated polypropylene additive (0 to 5 percent by weight) and of extrusion blending temperature (190T to 250°C) on the mechanical properties of extruded and injection-molded polypropylene-wood flour composites were investigated. The effects of maleated polypropylene additive on similarly processed polypropylene-wood flour and high density polyethylenewood flour composites were also compared. Both the additive and the high extrusion temperature led to some wood degradation and to a less polar wood surface. The additive led to greater reinforcement of the composites, as indicated by moderate but useful increases in heat deflection temperature, strength, and modulus. The major portion of those improvements was achieved by adding 1 to 2 percent additive. However, both the additive and the high extrusion temperature decreased impact resistance, presumably as a consequence of increased reinforcement by the filler particles and wood degradation. Heat deflection temperature, strength, and modulus of the polypropylene-wood flour system were marginally better than that of the high density polyethylene-wood flour system; impact resistance was marginally poorer.

Effect of particle size, coupling agent and DDGS additions on Paulownia wood polypropylene composites

“…Others have shown that the flexural behavior of the composites can vary significantly with the type of filler and coupling agent employed. 10,31 LPC containing a combination of STDDGS with PWF showed superior mechanical properties (except elongation values) compared to LPC composed of only STDDGS (Figure 3). LPC composed of 12.5% STDDG and 12.5% PW (PP-12.5PW/12.5STDDGS-MAPP) exhibited u , E, %El, E b , and impact strength values that were +15%, +61%, À79%, +78%, and À36%, respectively, of the values obtained from neat PP.…”

“…10,19,26,27,[29][30][31] Coupling agents act as intermediates to bind hydrophobic polyolefins to hydrophilic lignocellulosic materials (e.g., wood or DDGS). The mechanical testing results of the effect of the coupling agent concentration are graphically presented in Figure 1.…”

“…Other studies have shown this trend. 18,19,26,27,[29][30][31] Tensile strength is a measure of the stress load a material can support before generating voids that lead to crazing of the material and ultimate failure. The u increase is attributed to better transfer of stress between the hydrophobic wood fiber and the hydrophilic PP matrix due to the chemical coupling.…”

Sustainable biocomposites based on autohydrolysis of lignocellulosic substrates

“…The matrix-filler interface plays a critical role in ensuring that the properties of each component contribute optimally to the properties of the final product, and is affected by a number of factors, including the nature of interfaces, the operational conditions (which may result in thermal degradation) and superficial chemical changes which could adversely affect the bulk properties [37,38]. For example, this type of effects has been reported by Takase and Shiraishi [39] in the co-extrusion of polypropylene and wood flour at 250ºC.…”

Treated Tropical Wood Sawdust-Polypropylene Polymer Composite: Mechanical and Morphological Study

“…The authors would like to thank the University Malaysia Sarawak (UNIMAS) for providing the sponsorship under FRGS research grant (UNIMAS/ FGRS/02(20)/741/2010 [27] that has made this work possible.…”