BIAXIAL ORIENTATION OF POLY(VINYL CHLORIDE) COMPOUNDS - INTERACTION BETWEEN DRAWING, STRUCTURE, AND PROPERTIES

Rigid poly(vinyl chloride) (PVC) sheets were stretched uniaxially (at constant width), equally biaxially, and unequally biaxially to various draw ratios. Tensile properties, density, and birefringence of the st retched sheets were measured, and their wide angle X-ray diffraction t races recorded. Comparison of results showed the highest crystallite a nd overall orientation and density in the uniaxial samples, and lowest values for the equal biaxial samples. Drawing resulted in the alignme nt of some existing crystallites In the plane of the film, together wi th the formation of new mesomorphous structures. Changes in tensile st rength were attributed to overall orientation.