Characterization of biaxially oriented poly (vinyl chloride) and PVC-acrylic processing aid systems

The effects of the addition of an acrylic processing aid to a rigid poly(vlnyl chloride) compound (PVC MB) on the processing and post forming operations have been Investigated. The magnitudes of the stretch ratios obtainable as a funtlon of stretch temperature were studied for both the unmodified PVC and the PVC-acryllc processing aid systems. The addition of the acrylic processing aids Increased both the degree to which the PVC MB could be blaxlally stretched and the stretching temperature.

Birefringence was the chief tool for characterizing the orientation produced In the stretched films at the various conditions. The birefringence was observed to relate directly with the amount of biaxial orientation except when delamlnatlon was observed In the PVC MB.

The mechanical properties of the films were measured. The yield strength, tensile strength and Young's modulus Increased with orientation while the elongation to break decreased.