POLYOLEFIN WOOD FILLER COMPOSITE .1. PERFORMANCE OF M-PHENYLENE BISMALEIMIDE-MODIFIED WOOD FIBER IN POLYPROPYLENE COMPOSITE

The properties of the composite of polypropylene (PP) and chemithermom echanical pulp reactively treated with bismaleimide-modified PP or pre modified pulp have been investigated. The results were compared with t he properties of unmodified composites of PP and pulp. The effect of s ome flame retardants on the properties of composites was also studied. Premodifications of PP as well as pulp with m-phenylene bismaleimide provided a positive response with regard to the mechanical properties of the composites. The tensile strength of a 35 wt % pulp-filled PP co mposite was found to be much higher than that of the strength of pure PP. On the other hand, tensile strength decreased considerably with in crease in the chemithermomechanical pulp content if unmodified PP was used. The occurrence of chemical grafting reactions between PP and bis maleimide as well as between pulp and bismaleimide have been suggested , which can explain the aforementioned difference in mechanical proper ties among different composites. In situ addition of sodium berate, bo ric acid, or phenolic resin during processing of the composite decreas ed the rate of burning of PP. (C) 1994 John Wiley and Sons, Inc.