W. Zhou et al., Toughening of a high-temperature polymer by the sol-gel, in situ generation of a rubbery silica-siloxane phase, J APPL POLY, 79(13), 2001, pp. 2326-2330
A phenyl ether phenyl phosphate polymer, specifically poly(biphenyl ether t
riphenyl phosphate), was modified to increase its tractability and to impro
ve its toughness. The first goal was achieved by increasing its solubility
by sulfonation of the chain, and the second, by the in situ generation of a
rubbery phase. This phase was generated by a modification of the usual sol
-gel reaction (which usually generates a hard silicalike material by the hy
drolysis of a tetrafunctional organosilicate). In this case, a difunctional
silicate was included, thus introducing some softening organic groups into
the dispersed phase. A bonding agent, N,N-diethylaminopropyltrimethoxysila
ne, was also included to improve the bonding between the two phases in this
organic-inorganic composite. As expected, the glass transition temperature
s generally increased slightly upon sulfonation, but decreased significantl
y upon introduction of the rubbery phase. Most important, the toughness of
the polymer was successfully increased with, for example, only 8 wt % of th
e rubbery phase, quadrupling extensibility to 20 % and markedly increasing
the toughness. (C) 2001 John Wiley & Sons, Inc.