Preparation of natural rubber-g-methylmethacrylate/poly (vinyl chloride) blends

Abstract

The modification of natural rubber by graft copolymerization with methyl methacrylate (MMA) was studied. The effects of MMA content, reaction temperature, reaction time and NR latex concentration on the graft copolymerization were investigated. The grafting efficiency of grafted NR (GNR) determined by solvent extraction technique and degree of conversion were obtained. The grafted natural rubber was characterized by infrared spectroscopy (FTIR), the thermal properties were determined by Thermogravimetric Analyzer (TGA) and Differential Scanning Calorimetry (DSC) The physical properties of GNR/poly (vinyl chloride) (PVC) blend were studied. The effects of the MMA content, GNR/PVC ratio and the plasticizer content on properties of GNR/PVC blends were also investigated. Each composition was mixed on a two-roll mill; then the sheets were prepared by compression molding at 165℃. It was found that 300% modulus, tensile strength, tear strength, hardness, and solvent resistance were increased with increasing MMA content, while the % elongation at break decreased. The physical properties decreased with increasing the PVC content, but solvent resistance increased. The appropriate composition of GNR-60/PVC-P20 was 80:20. Their properties are as follows: 300% modulus was 20.88MPa, tensile strength was 22.01 Mpa, % elongation at break was 323%, tear strength was 59.70 N/mm, hardness was 94.68 IRHD and abrasion resistance was 0.2368 cm3/2000 cycle.