| Abstract: | The surface of poly(p-phenylene terephthalamide) (PPTA) fiber was modified by the polymer reaction via the metalation reaction in demethyl sulfoxide to provide the fiber surface with several functional groups such as the n-octadecyl group, carboxymethyl group, and acrylonitrile. The discontinuous fibers thus modified could be isotropically dispersed in polyethylene and ionomer. The composite of ionomer and random-in-plane oriented discontinuous PPTA fibers with the surface modified by carboxymethyl groups was remarkably improved in its mechanical properties, and the fiber efficiency factors of about 0.4 for both strength and modulus are comparable to the values in the composite of unidirectionally oriented discontinuous PPTA fibers and ionomer. The heat resistance of ionomer was also greatly improved by the presence of this surface modified PPTA fibers, even with volume fractions as low as 2.2%. |
