The Influence Of Morphology On The Mechanical Properties Of Crystalline Polymers

Abstract

Stress-strain curves and related mechanical parameters such as initial moduli, yield stress and fracture stresses have been measured for a variety of semicrystalline polymers possessing a range of controlled morphologies. The investigations described embrace (i) a study of the low-temperature properties of trans-polychloroprene with 18% crystallinity and morphologies varying from spherulitic to row-nucleated (‘shish-kebab’), (ii) a study of the properties of cis-polyisoprene with about 30% crystallinity and morphologies from spherulitic. through row-nucleated to fibrillar, tested both above and below Tg, and (iii) a study of the deformation of spherulitic polyethylenes with crystallinities from about 40% to 85% and after various doses of y-radiation. These studies taken together provide considerable insight into the respective roles of the crystalline and amorphous phases in determining high-strain mechanical properties. Simple but physically realistic two-phase models are proposed to explain many of the observations. © 1972, Walter de Gruyter. All rights reserved.