Thermal properties of aromatic polycarbonates copolymers based on bisphenol A and tetramethyl bisphenol A

摘要

Statistical copolycarbonates containing different bisphenol A/tetramethyl bisphenol A (BPA/TMBPA) molar ratios were synthesized by polycondensation reaction between a mixture of the two bisphenols and phosgene. The reaction conditions were selected for producing polymers having comparable molecular weights ((M) over bar (n)approximate to 9000 g/mol) but different composition, and the same composition but different molecular weights. The calorimetric properties of the products were investigated by differential scanning calorimetry (DSC) and dynamical-mechanical thermal analysis (DMTA). In particular, the effect of the copolymers molecular characteristics on the glass transition temperature (T-g) and the related relaxation processes were studied. DMTA was employed for evaluating the effect of macromolecular structure on the gamma low temperature relaxation peak.