Solid-state polymerization process for the preparation of poly(cyclohexane-1,4-dimethylene cyclohexane-1,4-dicarboxylate) polymers with high melting temperature and crystallinity

Poly(cyclohexane-1,4-dimethylene cyclohexane-1,4-dicarboxylate) has been prepared by solid-state polymerization using 1,4-cyclohexanedicarboxylic acid or its di-methylester and 1,4-cyclohexanedimethanol as monomers. The process consists in a first step in which a prepolymer with high crystallinity is prepared by melt polycondensation and then submitted to solid-state polymerization (SSP) at a temperature below the melting temperature of the polymer. The use of the solid state process permits to minimize the isomerization from the trans to the cis form in the polymer chain and therefore a polyester with higher crystallinity and melting temperature, compared to those synthesized by the traditional polycondensation routes, can be obtained. For this reason, the SSP process allows to obtain materials with thermo-mechanical properties that cannot be achieved using the standard polycondensation method. Moreover, the process does not involve a complex multi-step temperature ramp as in the case of the polycondensation process.