Dynamic mechanical relaxation effects in some poly(arylene sulfones)

Poly‐4,4′‐oxydiphenylenesulfonyl and poly‐4,4′‐methylenediphenylenesulfonyl were synthesized by an electrophilic substitution polymerization of the arylene monosulfonyl chloride monomers. The glass‐transition temperatures T g of these polymers were determined by calorimetric and dynamic mechanical measurements, and the number‐average molecular weights were determined by vapor‐pressure osmometry. Both polymers were found to have the same T g at equivalent molecular weight; the limiting value at high molecular weight is 238°C. Both polymers have two dynamic mechanical relaxation peaks at temperatures far below T g . One is in the neighborhood of 0°C, and the other is at −110°C. Plausible origins for these relaxations, and the absence of any near 0°C in poly(4,4′‐isopropylidenediphenylene‐ co ‐4,4′‐sulfonyldiphenylene dioxide), are discussed.