The synthesis of high-molecular-weight polyesters based on 1,43,6-dianhydro-~-sorbitol (DAS), 1,4:3,6-dianhydro-~-mannitol (DAM) and 1,4:3,6-dianhydro-~-iditol (DAI) is reported. The polymers were obtained by polycondensation in solution of the dianhydrohexitols with terephthaloyl dichloride and 2,5-diethoxyterephthaloyl dichloride. The side groups of the latter monomer lead to a marked improvement of the solubility of the resulting polyesters which can be characterized by NMR techniques and osmometry. It is shown that all polyesters exhibit an excellent stability against thermal decomposition. Materials deriving from the polycondensation with terephthalic acid have glass transitions above 200 "C if the molecular weight is high enough. The wide-angle X-ray analysis shows that polyesters deriving from terephthalic acid and DAM as well as DAI are semicrystalline. All results demonstrate that these polyesters partly deriving from renewable carbon sources present promising high Tg materials with excellent thermal stability. 0 1993, Hiithig & Wepf Verlag, Base1 CCC 0025-1 16X/93/$05.00
The synthesis and analysis of copolyesters based on 1,4: 3,6-dianhydrosorbitol (DAS), ethylene glycol, and terephthalic acid is described. It is shown that these copolyesters present materials stable up to elevated temperatures. The glass transition temperature, Tg, is shown to rise linearly with increasing content of DAS to reach values well above 100°C. Thus, DAS derived from renewable resources is a highly interesting diol component for making technical polyesters.
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