Reinforcement of Engineering Themoplastics with High Purity Wood Cellulose Fibers

摘要

High purity wood cellulose fibers (≥95% α-cellu-lose content) can provide good reinforcement properties for engineering thermoplastics melting above 200°C such as nylon 6 to yield mechanical properties that are intermediate between glass fiber and mineral materials such as wollastonite. Composite discoloration and decomposition are minimized using such high purity wood pulp fibers. At the levels employed (30% to 33% by weight), processing temperatures in both compounding and injection molding can be substantially lowered. Of six wood pulps studied, two with α-cellulose contents greater than 97 percent gave the best overall results with one of them appearing superior (a hardwood kraft pulp). In this study, pulp fibers were granulated with a rotary knife cutter prior to compounding them with nylon 6; this step reduced fiber length. It was later found that pelletizing the fibers helps preserve original fiber length, improves processing, and leads to better mechanical properties (at times exceeding those for glass fibers). Mercerization of the hardwood kraft fibers results in additional processing and mechanical property improvements. These studies with nylon 6 are presented and discussed in this paper along with some limited results obtained using certain process additives as well as other engineering plastics.