SYNTHESIS AND CHARACTERIZATION OF POLY(ETHER SULFONE) COPOLYMERS

Poly(ether sulfone) copolymers I-V were synthesized by the nucleophili c substitution reaction of 4,4-dichlorodiphenyl sulfone with varying m ole proportions of 4,4-isopropylidene diphenol (bisphenol A) and 4,4-d ihydroxydiphenyl sulfone (bisphenol S) using sulfolane as the solvent in the presence of anhydrous K2CO3. The polymers were characterized by different physicochemical techniques. The glass transition temperatur e was found to decrease with increase in the concentration of bispheno l A units in the polymers, All polymers were found to be amorphous. Th ermogravimetric studies showed that all the polymers were stable up to 400 degrees C with a char yield of about 36% at 900 degrees C in a ni trogen atmosphere. C-13-NMR spectral analysis reveals that bisphenol S -based triads are preferentially formed compared to bisphenol-A triads , indicating greater reactivity of bisphenol S toward dichlorodiphenyl sulfone. The overall activation energy for the thermal decomposition of bisphenol A-based polymer (I) is much higher than that of bisphenol S-based polymer (II). This was attributed to the modification of the backbone of polymer I during the initial cleavage of the C-CH3 bond of the isopropyledene group. Polymer II decomposes by cleavage of the C- SO2 bond. (C) 1998 John Wiley & Sons, Inc.