Wood-Plastic Composites (WPC) are composite materials made of wood fiber/ wood flour and thermoplastic(s) such as Polythene (PE), Polypropylene (PP), Polyvinyl Chloride (PVC), or Polylactic Acid (PLA). In addition to wood fiber and plastic, WPC can also contain other ligno-cellulosic and/or inorganic filler materials. WPCs are a subset of a larger category of materials called natural fiber plastic composites (NFPC), which may contain no cellulose-based fiber fillers such as pulp fibers, peanut hulls, coffee husk, bamboo, straw, digestate, etc. Chemical additives seem practically "invisible" (except mineral fillers and pigments, if added) in the composite structure. They provide for
integration of polymer and wood flour (powder) while facilitating optimal processing conditions.