Effect of solid-state modified polypropylene on the physical performance of sawdust-filled polypropylene composites.

The influence of solid?state modified polypropylene on the physical performance of uncoated or thermoset?resin coated sawdust?filled polypropylene composites was studied. The effect of composition of the composites on tensile strength, Young's modulus, tensile toughness, elongation, and impact strength was determined through two 23 factorial rotatable designs. The results of this investigation show that both the m?phenylene dismaleimide?modified polypropylene precompounded sawdust as well as solid?state modified maleated polypropylene can be successfully used to prepare sawdust?filled polypropylene composites with good tensile strength. On the whole, this property improved compared to that of unfilled polypropylene. According to the analysis of factorial design, the optimum composition to prepare a composite with highest tensile strength within the experimental range was 30-40 wt percent phenolic resin coated sawdust together with 4-6wt percent solid?state modified maleated polypropylene; while the product composition for the worst design was a combination of high amount of phenolic resin modified polypropylene with phenolic resin coated sawdust. The experimental design also concluded that effect of compositions on impact strength of composites was not significant in most of the cases. Overall, the empirical models constructed in this study provided a good approximation to actual experimental measurements; we are encouraged to extend this approach to processing conditions for manufacturing these composites. © 1993 John Wiley & Sons, Inc.