Effect of ‘‘blockiness’’ on the thermal transition of the terephthalate–adipate copolymers

Abstract

Now, it is well established that sequence distributions in copolymers greatly affect their thermal transitions. Random and block terephthalate–adipate copolymers, for instance, are known to have different thermal transitions while maintaining the same chemical structures. While no theory was able to fully predict the characteristics of the thermal transition of copolymers, modeling techniques have shown good reliance in simulating the copolymeric chains and related physical properties. This is done by generating representative sequences and studying the packing of such sequences into crystalline regions in multichain systems. The quantities of particular interest were the nature of the sequence distribution in random and block copolyesters, the degree of crystallinity, melting points, the standard free energy of fusion, interfacial free energies, and the moduli (calculated on the basis of the crystallites acting as cross-links in an elastomeric structure). The work is also capable of predicting the size and the distribution of the crystals and the minimum sequence length required for crystallization.