Phase transition, structure/properties of poly(p-phenylene terephthalamide) films post-polymerized by pyridine in NMP/CaCl2 solvent

Abstract

During polymerization of PPD(para-phenylene diamine) and TPC(terephthaloyl chloride) in NMP/CaCl2 solvent, the phase transition Iron isotropic to anisotropic phase was investigated. A reaction-induced transition point can be confirmed by a flat plateau indicative of the development of anisotropic phase in the torque-time curve and also can be identified by the striated band structure under shear. Water and pyridine were used as thecoagulating agent. Due to the post polymerization effect, the structures (crystallinity, orientation, fibrillation) and properties of films were affected by the shear given during the coagulation in pyridine.