PREPARATION OF CRYSTALLINE AND SOLVENT RESISTANT POLYCARBONATES VIA RING-OPENING POLYMERIZATION OF CYCLIC OLIGOMERS

A route to solvent-resistant polycarbonates which may also be crystall ine has been achieved through the intermediacy of cyclic oligomeric ca rbonates. Mixed oligomeric cyclics of a variety of bisphenols were pre pared via the carefully controlled hydrolysis-condensation of their bi schloroformates. following ring-opening polymerization, the polymers w ere evaluated for potential solvent resistance. Copolymers of hydroqui none and bisphenol A containing ratios of hydroquinone to BPA between 50/50 and 70/30 were found to be insoluble in CH2Cl2, tetrahydrofuran, and CHCl3, as well as other organic solvents. Polymers containing rat ios of hydroquinone/BPA greater than 60/40 show a crystalline melting point by DSC at about 310-degrees-C and a glass transition temperature at 154-degrees-C.