COMPUTER-SIMULATION OF SEQUENCE DISTRIBUTION OF POLY[(1,4-PHENYLENE TEREPHTHALAMIDE)-CO(1,3-PHENYLENEOXY-1,4-PHENYLENETEREPHTHALAMIDE)]

Sequence distribution of poly[(1,4-phenyleneterephthalamide)-co-(1,3-phenyleneoxy-1,4-phenyleneterephthalamide)] (Technora(R))) prepared by nonequilibrium copolycondensation, where solid terephthalic acid dichloride (TPC) was added to a solution of p-phenylenediamine (PPDA) and 3,4'-diaminodiphenylether (3,4'-DAPE), was investigated by means of computer simulation of the polymerization. The molecular weight distribution of oligomers, which were obtained under the conditions similar to the process of Technora(R) synthesis but with deviating monomer feed ratio from unity, was different from the theoretical value calculated by Flory's well-known equation. Thus the simulation model of the polymerization was modified so that the calculated molecular weight distribution would coincide with the experimental value. The simulation clarified that the conditions of dissolution and diffusion of TPC added as solid brought a change in the molecular weight distribution. The dissolution and diffusion parameters used in the simulation were estimated so as to coincide with the experimental values of the molecular weight distribution. The sequence distribution of Technora(R) given by the polymerization simulation, which was modified with the estimated parameters, was virtually equal to that of a statistical random copolymer due to a small difference in reactivity of the two diamines.