Synthesis and properties of copolyarylates containing phenol red units

A series of novel copolyarylates(co-PARs) containing phenol red units in the backbone were synthesized by interfacial polymerization at 10°C from bisphenol A (BPA), phenol red (PR) and diacid chloride monomers. The obtained copolyarylates (co-PARs) are all amorphous, the inherent viscosity ( η inh ) of 0.22–0.62 dl g −1 , and the number- and weight-average molecular weight are 10,200–46,200 and 38,600–203,600, respectively. Adding a small number of PR units to the molecular chains improved the processing fluidity of polyarylates, and the glass transition temperatures ( T g ) decreased from 202.8 to 166.7°C. In addition, the co-PARs have excellent thermal stability with the maximum thermal decomposition temperature of 532.4–545.2°C. The co-PARs show the best mechanical properties (57.6 MPa) when the PR content is 15 mol%. The transmittances of the co-PARs at 400 and 450 nm are 79.2%–97.9% and 87.0%–99.8%, respectively, and the cut-off wavelength is between 320 and 328 nm. The designed and synthesized copolyarylates can be considered as a promising and easy-to-process high-performance engineering plastic.