Dependence of Mechanical Properties on Crystalline,Intermediate,and Amorphous Phases in Poly(Ethylene Terephthalate) Fibers

Abstract

Crystalline, intermediate, and amorphous phase indices have been obtained for poly (ethylene terephthalate) fibers of different draw ratios. Azimuthal x-ray diffraction from the (010) plane is used for such an analysis. The intermediate phase is found to be linearly dependent on the draw ratio of the fibers. Experiments like shrinkage, dynamic, and static mechanical properties have been carried out for these samples, and an attempt is made to relate these properties with different phase indices. Storage modulus, loss modulus, initial modulus, strength, and shrinkage are linearly dependent on the intermediate phase. The elongation is found to be essentially determined by the amorphous phase index. The results provide further evidence for the existence of three phases in drawn PET fibers.