Hybrid composites : combining cellulose fibers and wollastonite mineral fibers into a nylon 6 matrix

Abstract

The objective of this research was to develop a high purity cellulose/wollastonite pellet that could then be accurately metered and feed into a laboratory scale twin-screw extruder and compounded with a nylon 6 resin. The major focus was targeted on a 20 percent cellulose/20 percent wollastonite/60 percent nylon 6 composite. Limited research with nylon 6,6 resins was also attempted and will be discussed briefly. A process for developing a cellulose/wollastonite pellet was successful and 100 Kg were produced for twin screw extrusion processing with nylons. The 100 Kg of pellets were then compounded via a “low temperature compounding” technique as discussed in detail elsewhere (1). Further information can be obtained in U.S. Patent #6,270,833 B1 (2). The compounding process research was to determine if composites could be produced in small batches (50 Kg trial runs) on laboratory scale twin-screw extrusion compounding equipment. The result was 125 Kg of composite material for injection molding and ASTM mechanical property evaluation. Attempts to maximize the composite properties were not the focus of this research. Stable, controllable processing characteristics and repeatability of the twin-screw extrusion trials was the goal. It is the authors’ opinion that this goal was accomplished. Future research will focus on maximizing composite properties and determining if cellulose fibers alone or in combination with mineral fibers can be compounded on larger commercial scale equipment. Extreme care and precise processing knowledge is needed to develop a commercial scale process that works. If this cannot be accomplished, then cellulose fibers as reinforcement in any of the high melting point engineering thermoplastics may remain as a laboratory oddity.

Citation

Jacobson, Rodney E.; Caulfield, Daniel F. 2003. Hybrid composites : combining cellulose fibers and wollastonite mineral fibers into a nylon 6 matrix. Seventh International Conference on Woodfiber-Plastic Composites (and other natural fibers) : May 19-20, 2003 ... Madison, Wisconsin. Madison, WI : Forest Products Society, 2003: Pages 271-276