Use of wood fibers in thermoplastic composites

Wood fibers from aspen and spruce have been used for filler and reinforcement of polystyrene. The wood fibers used were in the form of refined wood. In order to improve compatibility of wood fibers with polymeric matrices, fibers have been modified by copolymerization with styrene. The kanthate method of grafting employing the ferrous‐hydrogen peroxide catalytic system was used for fiber treatment. The following properties of composites have been measured: elastic‐modulus, tensile strength, and energy absorbed at break. In summary, it has been found that the composites from grafted fibers showed superior mechanical properties to those with original fibers. In general, as a filler, the aspen fibers were superior to spruce, and the shorter fibers superior to longer ones. Mechanical properties of composites as compared to polystyrene were improved as follows: elastic modulus +37 percent; tensile strength +35 percent and energy at breakup by 43.5 percent. The best composites properties have been achieved at 40 percent of fiber fraction present.