Natural rubber-g-methyl methacrylate/poly(methyl methacrylate) blends

Modification of natural rubber by graft copolymerization with methyl methacrylate monomer (MMA) was studied. The effects of initiator concentration, reaction temperature, monomer concentration and reaction time were investigated. Grafting efficiency of the grafted natural rubber (GNR) was determined by solvent extraction technique. The grafted natural rubber was characterized by FT-IR. Dynamic mechanical properties and morphology of grafted natural rubber was found as follows: the rubber content 100 phr, the initiator concentration 0.75 phr. the reaction temperature 55°c, the monomer concentration 100 phr, and the reaction time 8 hours. Mechanical properties of the GNR/poly (methyl methacrylate) blends and surface morphology by SEM were studied. The effects of GNR/PMMA ratio were also investigated. Compression molded sheets of various compositions gave the following properties: hardness. Stress at maximum load, and tear strength increasing of PMMA content. For GNR100/PMMA blends with PMMA content above 30%, the tear strength decreased with increasing PMMA content.