Synthesis of a Regioregular Series of Poly(aryl ether carbonates) and Their Glass Transition Temperatures

Abstract

Bisphenol A polycarbonate (BPA-PC) is a remarkable high-performance engineering polymer, although it is susceptible to photo-Fries and hydrolytic degradation. New poly(aryl ether carbonates) were synthesized to address these limitations by replacing the chain backbone carbonate ester functionality with aryl ether functionality. The monomers for these new polymers were synthesized by a variation of the Ullmann condensation accelerated by 2,2,6,6-tetramethylheptane-3,5-dione and promoted by Cs2CO3 and 1-methyl-2-pyrrolidinone under mild conditions. Four such bisphenol A-based diarylether monomers containing different mass ratios of carbonate ester groups were prepared and polymerized with phosgene gas to give novel poly(aryl ether carbonates). Polymers were named as di-o-BPA-PC 9′, tri-o-BPA-PC 11′, tetra-o-BPA-PC 13′, and penta-o-BPA-PC 15′ where di-, tri-, tetra-, and penta- reflect the number of diphenylisopropylidene units in each of the respective polymers. The molecular weights of the resulting four poly(aryl ether carbonates) were measured by gel permeation chromatography. Differential scanning calorimetry was used to measure glass transition temperature (Tg). The polymers exhibited weight-average molecular weights up to 4.09 × 105 g/mol and Tg in the range of 136 to 149 °C with no melting temperature peak, indicative of their amorphous character. The new polymers formed transparent and flexible films by solution casting from chloroform solution.