Effect of surface modified filler on mechanical properties of rigid poly(Vinyl chloride) opaque sheet

Abstract

This research studied the effects of type, concentration, and mixed of ratio surface modified fillers on mechanical properties and thermal properties of rigid poly(vinyl chloride) opaque sheet (R-PVCOPS). In production of R-PVCOPS via a calendaring process, fillers of CaCo3’ kaolin and/or talcum at a ratio of 5, 10 and/or 20 phr were mixed, at a varied type and concentration, in a two-roll mill to gives a sheet with 0.3 mm thickness. The mechanical properties understudy are tensile strength, tear strength, impact strength; thermal properties as the percentage of shrinkage, and heat deflection temperature. On the mechanical property test, it was found that increases in concentration of the single filler, tensile strength, tear strength and impact strength increased, but percentage shrinkage decreased. When two or three types of fillers were mixed, a greater increase in tensile strength, tear strength and impact strength and marked decrease in above-mentioned values were found at an increased filler concentration to 20 phr, whereas the heat deflection temperature insignificantly decreased. Upon examination by scanning electron microscopy, particle size distribution of the fillers among the molecular chains of R-PVCOPS containing 20 phr filler decreased, which resulted in rough surfaces of the sheets. The optimum conditions for producing R-PVCOPS by a calendaring machine are the 1/1 ratio of calcium carbonate/talcum to a total filler concentration of 10 phr. The properties obtained are tensile strength of 609±2.61 kg/cm2, tear strength of 67±0.34 kg/cm, and impact strength of 7.6±0.05 kg/cm. The commercial rigid poly(vinyl chloride) sheets have tensile strength, tear strength and impact strength of 420±50 kg/cm2, 32±20 kg/cm, and 1.4±2.0 kg/cm, respectively. The R-PVCOPS so prepared could increase both mechanical and thermal properties and reduce production cost of poly(vinyl chloride) resin.