Emülsi̇yon poli̇meri̇zasyonu i̇le doğal kauçuk üzeri̇ne sti̇ren aşılanması

NR has unique and special properties, including high tensile strength, high elongation, and outstanding resilience. It has gained more importance in industry due to its environmental preservation and being renewable source. However, natural rubber is weak in oil resistance, weather resistance, and ozone resistance because of unsaturated carbon double bonds. Some curing techniques and physical and chemical modifications have been developed to get better weathering stabilization of natural rubber. The chemical modification of NR by grafting with vinyl monomers combines the properties of NR and the monomer grafted. The most widely used vinyl monomers are methyl methacrylate, styrene, acrylonitrile. Many research in literature about the graft copolymerization of natural rubber have confirmed that St is one of the most suitable monomers when polymerized to give a high level of grafting, and also provides better ozone, heat, and weathering resistance. Graft copolymerization of St onto NR molecule has been performed by free radical polymerization in emulsion states using various initiator systems including thermal and redox initiators. This work deals with the graft copolymerization of St onto NR in emulsion state by free radical polymerization. The aim of this study was the graft copolymerization of Styrene (St) onto unsaturated carbon double bonds of Natural Rubber (NR) to improve the environmental resistance (UV, heat). The graft copolymerization of St onto NR was performed using ammonium persulfate (APS) as initiator in the emulsion polymerization at a temperature of 85 0C for 4 hours. The graft copolymerization was also carried out by varying the concentrations of initiator and reaction temperature. The grafting efficiency, graft ratio, particle size, and monomer conversion results were compared. The obtained copolymer composition was determined by nuclear magnetic resonance spectroscopy (NMR) and fourier-transform infrared spectrophotometer (FT-IR). The percentage of residual monomer was analyzed by gas chromatography (GC). The Styrene grafted Natural Rubber (St-g-NR) was applied as antislip carpet back-coating. The UV resistance and heat resistance of St-g-NR was tested by using accelerated weathering tester according to ASTM G154 Standard Practice for Operating Fluorescent Ultraviolet Lamp Apparatus for Exposure of Nonmetallic Materials.