Effect of Styrene-Methyl Methacrylate/Styrene-Butadiene Rubber on Properties of Poly(vinyl chloride)

Generally, poly(vinyl chloride) (PVC) without the addition of plasticizer or impact modifiers is rigid and brittle. The aim of this research was to improve the mechanical properties of PVC using styrene-methyl methacrylate/styrene-butadiene compound (SMMA/SBR rubber) as an impact modifier. The compound was obtained commercially. PVC containing SMMA/SBR rubber having SMMA/SBR contents of 2.5, 5, 7.5 and 10 phrs were prepared using two-roll mill set the conditions as follows: 170 degrees C and 5 minutes. Then, compression molding was carried out to prepare testing samples. FTIR analysis of SMMA/SBR rubber containing PVC samples showed the absorption band at 1732 cm(-1) (C=O stretching), 3025 cm(-1) (=C-H stretching) and 636.8 cm(-1) (C-Cl band). The PVC and SMMA/SBR rubber were compatible due to the specific interaction between carbonyl groups (C=O) of methyl methacrylate and hydrogen atom of PVC CH-Cl group that was confirmed by a slight shift of absorption band of methyl methacrylate carbonyl groups to lower wave number. The effects of SMMA/SBR rubber on mechanical properties, including impact strength and tensile properties were evaluated by standard tests. The impact strength of SMMA/SBR rubber containing PVC increased significantly with an increase in the SMMA/SBR content (ex. SMMA/SBR 5 phr and 10 phr produced impact strengths of 3.30 and 6.38 kJ/m(2) respectively), resulting from the action of SMMA/SBR rubber phase as impact modifier as revealed by SEM images. Furthermore, modulus, tensile strength and elongation at break and plasticizer migration ability were investigated.