Synthesis and characterization of aromatic copolyesters derived from bisphenol B and phenol red

A series of novel aromatic copolyesters derived from bisphenol B (BPB) and phenol red (PR) were synthesized by interfacial polymerization. The number- and weight-average molecular weight (M-n and M-w) of the obtained amorphous aromatic copolyesters ranged from 1.06-1.80 x 10(4) to 2.01-6.17 x 10(4) g/mol, respectively. Density functional theory calculations showed that the reactivity of BPB was similar to that of bisphenol A. The reaction activation energy of BPB with terephthaloyl and isophthaloyl chloride (TPC and IPC) was 8.23 kcal/mol, and PR with IPC and TPC was 59.30 kcal/mol. Under the influence of the ethyl side group of BPB and the pendant group of PR, the solubility of the aromatic copolymer was improved, and the glass transition temperature (T-g) was 125.1-195.3 degrees C, while T-max could still be maintained above 525.72 degrees C. The optical transmittance of the copolyesters at 450 nm (T-450) was 69.29%-99.41%, and the tensile strength and Young's modulus were in the range of 46.79-58.59 MPa and 1.39-1.86 GPa respectively. All aromatic copolyesters exhibit good mechanical and processability properties and have great application potential as high-performance plastics.