Novel copolycarbonates containing 1,4:3,6‐dianhydro‐ D ‐glucitol or 1,4:3,6‐dianhydro‐ D ‐mannitol units, with various methylene chain lengths, were synthesized by bulk and solution polycondensations, of several combinations of carbonate‐modified sugar derivatives and aliphatic diols. Bulk polycondensations of 1,4:3,6‐dianhydro‐2,5‐bis‐ O ‐(phenoxycarbonyl)‐ D ‐glucitol or 1,4:3,6‐dianhydro‐2,5‐bis‐ O ‐(phenoxycarbonyl)‐ D ‐mannitol with four α,ω‐alkanediols having methylene chain lengths of 4, 6, 8, and 10, respectively, at 180 °C afforded the corresponding copolycarbonates with number‐average molecular weight ( M n ) values up to 19. 2 × 10 3 . 13 C NMR analysis disclosed that these polymers had scrambled structures in which the sugar carbonate and aliphatic carbonate moieties were nearly randomly distributed along a polymer chain. However, solution polycondensations between 1,4:3,6‐dianhydro‐2,5‐bis‐ O ‐( p ‐nitrophenoxycarbonyl)‐ D ‐glucitol or 1,4:3,6‐dianhydro‐2,5‐bis‐ O ‐( p ‐nitrophenoxycarbonyl)‐ D ‐mannitol, and the α,ω‐alkanediols in sulfolane or dimethyl sulfoxide at 60 °C gave well‐defined copolycarbonates having regular structures consisting of alternating sugar carbonate and aliphatic carbonate moieties with M n values up to 33. 8 × 10 3 . Differential scanning calorimetry demonstrated that all the copolycarbonates were amorphous with glass‐transition temperatures ranging from 1 to 65 °C, which decreased with increasing lengths of the methylene chain of the aliphatic diols. Additionally, all the copolycarbonates were stable up to 310–330 °C as estimated by thermogravimetric analysis.
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Yokoe et al. (2003) studied this question.