SYNTHESIS AND INVERSE GAS-CHROMATOGRAPHIC CHARACTERIZATION OF POLYESTERS CONTAINING PYRIDINE UNITS IN THE MAIN-CHAIN

Aromatic polyesters with isophthaloyl, pyridine-2,6-dicarbonyl and pyr idine,2,5-dicarbonyl units in the main chain were synthesized and were characterized by inverse gas chromatography (i.g.c.). The polyesters containing complex 'triad' monomers and aromatic diols were obtained b y high temperature solution polycondensation. In order to investigate whether the surfaces of polycondensates act as Lewis acids or Lewis ba ses, the donor-acceptor interactions between various probe molecules a nd polyesters have been studied by means of i.g.c. Because the measure ments were carried out at different temperatures, we were able to dete rmine parameters K-A and K-B, which describe the donor-acceptor proper ties of the stationary phase. One polyester without pyridine units was amphoteric with slight predominance of Lewis-basic behaviour. Polymer s containing pyridine units may be considered as Lewis bases. The glas s transition temperatures of two polymers have also been determined by i.g.c. (C) 1997 Elsevier Science Ltd.