INSITU EMULSION GRAFT COPOLYMERIZATION OF STYRENE AND METHYL METHACRYLATE ONTO LOW PROTEIN CONTENT OF HEVEA NATURAL RUBBER LATEX Santi Puspitasari
Indonesian Rubber Research Institute
Abstract
Thermal stable and hydrocarbon solvent resistance of thermoplastic natural rubber (TPNR) was prepared by insitu emulsion graft copolymerization of vinyl monomers (methyl methacrylate and styrene) onto low protein content of Hevea natural rubber (DPNR) latex by using 1% ammonium peroxydisulfate and 3% sodium dodecyl sulfate at 65oC for 5 h continued at 70oC for 1 h. The degree of grafting, physical and thermal properties of TPNR were studied as a function of vinyl monomer and DPNR ratio. The attachment of vinyl monomer onto DPNR backbone is confirmed by FTIR spectroscopy indicated by the dissappereance of peak intensity around 1663 cm-1 belongs to C=C bonds on DPNR molecular chain. The result showed that increasing proportion of vinyl monomer to DPNR exhibits higher degree of grafting. TPNR from attachment of methyl methacrylate has good hydrocarbon solvent resistancy. Meanwhile, an thermal stable TPNR was produce from styrene branching on DPNR molecule.
