Poly(ethylene terephthalate) terpolyesters containing 1,4-cyclohexanedimethanol and isosorbide

A series of poly(ethylene terephthalate) terpolyesters containing varying amounts of both 1,4-cyclohexylenedimethylene and isosorbide units were prepared by melt phase polycondensation. These terpolymers were obtained with high molecular weights and polydispersities around 2.0–2.5. The nuclear magnetic resonance data revealed that they were all random terpolymers and that small amounts of isosorbide were lost during the polycondensation reaction. Thermal data showed that terpolymers with 90 mol% of ethylene units were crystalline, whereas the two other series containing 80 and 70 mol% were unable to crystallize from the melt. For the three series studied, it was observed that the glass transition temperature increased steadily with the content of isosorbide units, and that they had similar thermal stability.