INTERDIFFUSION MEASUREMENTS OF MODIFIED POLY(ARYLETHER SULFONE)S USING NUCLEAR-REACTION ANALYSIS

The interdiffusion and miscibility behavior of three different types o f modified poly(arylether sulfone)s with deuterated poly(arylether sul fone) is studied by depth profiling using the nuclear reaction D(He-3, alpha)p. The diffusion coefficients are found to be in the range of 1 0(-15) and 10(-14) cm(2)/s at 195 degrees C. A random copolymer of pol y(arylether sulfone) containing 4,4-bis-(4'-hydroxyphenyl) valeric aci d units is only partially miscible with deuterated poly(arylether sulf one) when the comonomer content is 8.8 mol %, whereas blends with como nomer contents of 1.7 and 4.5 mol % are miscible as indicated by compl ete interdiffusion. The transition from miscibility to immiscibility i s caused by repulsive interactions of copolymer segments and can be ex plained in terms of a mean-field theory of random copolymer blends. Al so, poly(arylether sulfone)s grafted with 0.4 wt % maleic anhydride or having pyromellitic anhydride endgroups are miscible with deuterated poly(arylether sulfone)s. (C) 1997 John Wiley & Sons, Inc.