A NEW MODEL DESCRIBING THE COCRYSTALLIZATION BEHAVIOR OF RANDOM COPOLYMERS

We have developed a new model to describe the melting point depression of isomorphic copolymers. The model combines the common models applie d for nonisomorphic and isomorphic copolymers and is capable of fittin g the transition between both assuming the concentration dependence of the mean defect Gibbs energy. The model is tested with success on a s et of melting temperatures of copolymers from ethylene terephthalate a nd ethylene 2,6-dicarboxynaphthanoate (PET and PEN), demonstrating the influence of defect aggregation during copolymer crystallization. The comparison of the model fits to the free energy values for comonomer inclusions from thermodynamic-integration simulations, making obvious the power of that computational method.