(Co-)Polyesters Derived from Isosorbide and 1,4-Cyclohexane Dicarboxylic Acid and Succinic Acid

The homopolyester of isosorbide and cis-trans 1,4-cyclohexane dicarboxylic acid (CHDA) was prepared by three different methods, but only polycondensation of isosorbide and CHDA dichloride yielded a satisfactory molecular weight (corrected (M) over bar (n) = 11 000 Da). For the best sample the MALDI-TOF mass spectrum revealed a high content of cycles. The homopolyester of CHDA and isomannide or isoidide was prepared analogously. For the homopolyesters of CHDA high glass transition temperatures were found (T-g = 146 degrees C for isosorbide, 133 degrees C for isomannide, and 115 degrees C for isoidide), whereas the polyester of isosorbide and succinic acid (SuA) has a Tg around 77 degrees C. Copolyester of isosorbide and various molar ratios of CHDA and SuA were prepared by two different methods, but only rather low molecular weights were obtained. SEC measurements with and without "universal calibration" revealed that the normal calibration with polystyrene overestimates the real molecular weights by 30-45%.