Toughening of some high-temperature poly(arylene ether)s and a hydroxypoly(benzoxazole) by sol–gel generated rubbery particles

Some high-temperature polymers, specifically two poly(arylene ether)s and a hydroxy(benzoxazole) copolymer (HPBO), were toughened using dispersed rubbery phases generated by the sol–gel process. These rubbery phases were introduced using combinations of sol–gel precursors with varying numbers of alkyl groups. Scanning electron micrographs showed uniformly dispersed particles in these composite materials. In poly(arylene ether)s, a significant increase in toughness and ultimate elongation were achieved for samples prepared from relatively large amounts of sol–gel precursor with higher numbers of alkyl groups. In HPBO, samples having low levels of the rubbery phase, both toughness and ultimate elongation were increased with increasing amount of the rubbery phase. Improvements in these properties of the HPBO polymer are rather large compared to the poly(arylene ether)s. The results also demonstrated improved thermal properties and decreased water absorption.