Plastics Beyond HDPE in Wood-Plastic Composite Materials

Plastics Beyond HDPE in Wood-Plastic Composite Materials 

Attention in 1990s was paid to alternative thermoplastic materials (e.g., other than polyethylene). 

046 (all three— by Advanced Environmental Recycling Technologies, Inc.) disclose a composite made of 40-60% of plastic (LDPE, or a combination of 60% LDPE and 40% HDPE, or having 10-15% of polypropylene of the total amount of plastic) and about 60-40% of wood fiber. 

772 [75] discloses a cellulose-fiber-reinforced thermoplastic composition for compression molding, where thermoplastic material is polypropylene, or a mixture of polypropylene, polystyrene, and polyethylene (40-90% of plastic by weight), and the cellulosic material (10-60% by weight) was milled scrap newspaper with an initial moisture content of at least 30% by weight. The patentees suggest that lignin present in the cellulosic scrap provides a coherent mass of thermoplastic and cellulosic material. 

602 [85] discloses a composite comprising polypropylene, polyethylene, or their combination along with lignocellulosic particles (50-70% by weight) and a polyurethane coupling agent (15-3% by weight of the mixture). 

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