Mechanical Properties and Thermal Stability of methyl methacrylate grafted latex and natural rubber latex foam blends

© School of Engineering, Taylor’s University. Graft copolymerisation has been and is still globally used as one of the main methods of modifying natural rubber in both latex form and solution. Plenty of researches can be found on the application of graft copolymerization to reinforce natural rubber latex, but research on incorporating grafted rubber into natural rubber latex foam (NRLF) is yet to be done. The purpose of this study was to investigate the effect of methyl methacrylate grafted rubber latex (MGL) loading on the mechanical properties of the compounded NRLF. The blended latex was prepared by mixing high ammonia natural rubber latex and the industry-standard polymethyl methacrylate (PMMA)-grafted natural rubber latex, referred to as MG49. Then, the blended latex was compounded and processed into NRLF at a laboratory scale via the Dunlop process. A comparative study between the NRLF produced with varying MGL percentage, i.e., 0% (control), 10%, 20%, 30%, 40% and 50% was done. The hardness, compression set and stiffness of the NRLF increased as the percentage of MGL content in the NRLF increased. The addition of MGL in the NRLF showed a decrease in the thermal stability of the NRLF for temperatures below 400 °C, but no significant trend for higher temperatures. NRLF samples with higher MGL content also showed a tendency to swell more when soaked in toluene.