Bisphenol A-based polycarbonates: characterization of commercial samples

Poly(bisphenol A carbonate) (BPAPC) commercial samples were characterized by several techniques: DSC, TG, FTIR, SEC, VPO and viscometry. The samples presented the same FTIR spectrum profile and almost the same values of glass transition temperature and initial temperature of degradation. However, slight differences were observed in DTG curves, which may be due to the presence of additives. The number-average molecular weight of the samples, as received and purified, was determined by VPO, in two different solvents (CHCl3 and THF). Viscometric average molecular weights were obtained in CHCl3, at 25 degreesC. Five different equations were used to calculate intrinsic viscosities and viscometric constant values: Huggins, Kraemer, Schulz-Blaschke, by graphic extrapolation, and Solomon-Ciuta, Deb-Chanterjec and again Schulz-Blaschke, by a single point measurement. Relative molecular weights and polydispersities were determined by SEC, in THF at 35 degreesC, and in TCB at 135 degreesC. It was verified that the results obtained in the latter solvent were in better accordance with those obtained by the other techniques. (C) 2001 Elsevier Science Ltd. All rights reserved.