Wood fiber reinforced thermoplastic composites are usually manufactured by the extrusion method. However, the size of the extruded board and bio-fibers are limited. The objective of this study was to manufacture large size straw— polymer composite panels by hot-pressing method, focusing on the forms of raw materials and heating method. Wheat straw was reduced to particles and high density polyethylene (HDPE) was processed into fibers or powders. After mixing, preheating, hot-pressing, and cooling, the resulted panels were tested for mechanical and water resistance properties. The data indicated that HDPE in the form of fiber presented better properties than those in powders and preheating treatment before hot-pressing was an effective way to improve the mechanical properties of the straw— PE composite. Coupling agent helped to improve the bonding strength.

Wheat-Straw-HDPE Composite Produced by the Hot-pressing Method:

A kind of recycled polypropylene was selected as a raw material to make composite with wood fibers.This study evaluated the effect of polypropylene content,additives,density,and fiber size on the performance of the wood-plastic composite.The result showed that increasing polypropylene content improved the overall board performance.Adding additional binders to the wood-plastic composite manufacturing process reinforced the fiber-bonding which could in turn enhance the board properties.Increasing the product's density was the most effective way to improve bending properties.Fiber geometry was also found to affect board bending properties.It was recommended the following process parameters: 40% recycled polypropylene,2% PAPI additive need to be used in making the wood-plastic composite with board density of 1.05 g/cm3.

Chang Liang

Papers

Properties of Recycled-Polypropylene/Wood-Fiber Composites