Waste-Wood-Derived Fillers for Plastics

Filled thermoplastic composites are stiffer, stronger, and more dimensionally stable than their unfilled counterparts. Such thermoplastics are usually provided to the end-user as a precompounded, pelletized feedstock. Typical reinforcing fillers are inorganic materials like talc or fiberglass, but materials derived from waste wood, such as wood flour and recycled paper fiber, are also effective as fillers. The goal of this project was to generate commercial interest in using waste-wood–paper-derived fillers (WPFs) to reinforce thermoplastics. The research strategy was twofold: developmental research and outreach. Specific objectives were (1) to improve wastepaper fiber preparation, feeding, and compounding methods, and optimize composite performance, and (2) to communicate to end-product manufacturers the advantages of WPF thermoplastics. The research was led and supported by the Forest Products Laboratory (FPL), with input from a consortium of 15 fiber suppliers and plastics manufacturers. Additional funding was provided by the Wisconsin Department of Natural Resources. Equipment was leased and installed at FPL. Eight general purpose formulations were developed—they included extrusion and injection molding grades of both polyethylene and polypropylene, reinforced with WPFs. An information packet containing performance data, appropriate processing conditions, sample pellets, sample parts, and a questionnaire was sent to nearly 500 commercial