COMPUTER-SIMULATION OF AROMATIC POLYESTERS INCLUDING MOLECULAR-DYNAMICS

A theoretical analysis of the possible conformations of poly(p-phenylene terephthalate) (PPTA) and poly(p-phenylene isophthalate) (PPIA) is performed on the basis of molecular mechanics and molecular dynamics trajectories. An algorithm for creating long polymer chains up to 150 monomers used for the calculation of the small-angle X-ray form factor is introduced. Three different methods to determine the experimentally accessible property, persistence length, are presented. The results of all three methods agree very well with the experimental result for the persistence length of PPTA; in addition, the relationship between stiffness and persistence length is elucidated by comparison of the two different conformations of PPTA and PPIA.