Synthesis and characterization of poly(ether sulfone) and poly(ether sulfone ketone) copolymers

Poly(ether sulfone) and poly(ether sulfone ketone) copolymers (I-V) were sy nthesized by the nucleophilic substitution reaction of 4,4'-dihydroxy diphe nyl sulfone (DHDPS, A) with various mole proportions 4,4'-difluoro benzophe none (DFBP, B) and 4,4'-difluoro diphenyl sulfone (DFDPS, C) using sulfolan e as solvent in the presence of anhydrous K2CO3. The polymers were characte rized by physicochemical and spectroscopic techniques. All polymers were fo und to be amorphous, ana the glass transition temperature (T-g) was found t o increase with the sulfonyl content of the polymers. C-13-nuclear magnetic resonance (NMR) spectral data was interpreted in terms of the compositiona l triads, BAB, BAG, CAC, ABA, and ABB, and indicate that transetherificatio n occurs at high concentration of DFBP units in the polymer (TV). The good agreement between the observed and calculated feed ratios validates the tri ad analysis. Thermal decomposition studies reveal that the thermal stabilit y of the polymers increases with increase in the carbonyl content in the po lymer. Activation energies for thermal decomposition were found to be in th e range of 160-203 kJ mol(-1) with the cleavage of phi-SO2 bond being the p reponderant mode of decomposition and depended on the block length of the s ulfonyl unit. (C) 1999 John Wiley & Sons, Inc.