Effect of Di(2-ethyl hexyl phthalate)/Epoxidized Soybean Oil and Calcium Stearate/Zinc Stearate Ratios on the Tensile Properties of Plasticized PVC Formulations. A Study for Calcium Stearate Rich Formulations

Two series of plasticized PVC formulations were prepared, containing one of the following di (2-ethyl hexyl phthalate)/epoxidized soybean oil ratios (phr/phr): (a) 35/3, (b) 55/3, (c) 45/0 or, (d) 45/6. For each ratio, the following calcium stearate/zinc stearate ratios (phr/phr) were considered: (a) 0.6/0.4, (b) 0.8/0.2 or, (c) 1.0/0.0; all formulations were prepared with a total content of stearate(s) of 1.0 phr. The difference between the series was the preheating of stearates (150 °C, 90 min), carried out before the dry-blend preparation. The changes of tensile properties produced by the degradation process were measured in ribbons obtained by extrusion.