Composites of polypropylene (PP) or maleic-anhydride-modified polyprop
ylene (MAH-PP) with uncoated or thermosetting resin-coated sawdust or
explosion pulp (V-pulp) were prepared by dynamic cross-linking and the
ir properties were compared to those of unmodified and uncross-linked
composites. The effects of modification and dynamic cross-linking on t
he interfacial adhesion between polymer and filler have also been inve
stigated by a solvent extraction study and microscopic analysis. The n
ew method of dynamic cross-linking in combination with the additional
effect of compatibilization suggests a practical route to obtain high-
strength, toughened thermoplastic composites. Dynamically cross-linked
epoxy-or phenolic resin-coated sawdust or V-pulp that can be grafted
or can have affinity to MAH-PP was found to improve tensile strength a
s well as elongation at yield point. The tensile toughness of the dyna
mically cross-linked-compatibilized composites is better than that of
an uncross-linked composite of MAH-PP and sawdust. The improved toughn
ess of the dynamically cured composites appears to be that further che
mical bonds form between coated filler and MAH-PP in addition to graft
ing of MAH-PP onto cellulose chain.