The effect of processing parameters on cell structure and mechanical properties of extrusion-foamed poly(vinyl chloride) sheets

The objective of this study was to investigate the effect of processing parameters on cell structure and mechanical properties of extrusion-foamed poly(vinyl chloride) sheets. For this purpose, the effects of screw speed and die temperature on cell morphology, density, and mechanical properties, including tensile strength, elongation at break, flexural strength, and notched impact strength of the foam samples, were determined under the same conditions. The experimental results indicated that the extrusion-foaming process was comparatively stable as the screw speed changed in the range of 5.5-8.5 rpm. It was also shown that the lower the die temperature, the higher the die pressure and pressure drop rate, which is conducive to uniform bubble nucleation. In addition, the lower die temperature was beneficial for bubble solidifying and shaping. Therefore, in the range of temperature allowed, the lower the die temperature, the foamed poly(vinyl chloride) sheets with better cell structure and mechanical performance can be obtained. J. VINYL ADDIT. TECHNOL., 22:377-383, 2016. (c) 2014 Society of Plastics Engineers