Studies on the Interfacial Interaction in Natural Rubber Latex/Chitosan Blends

Abstract Chitosan (CS) has been blended with natural rubber (NR) latex by solution casting method followed by compression molding at 140°C. The blend is found to be incompatible from DSC, morphology and FTIR studies. The water absorbability of blends increases with increasing percentage of chitosan in the blend. Blending has improved the thermal properties of chitosan. The blended samples show enhanced mechanical properties. From the study of mechanical properties, it is found that there is good adhesion between the two phases. The interfacial adhesion is attributed to the presence of proteins and lipids at the surface of the rubber particles in the latex acting as a compatibiliser between chitosan, a polar polymer and rubber a nonpolar polymer. The interfacial adhesion may be due to interfacial interaction between the carboxyl groups of protein present in the latex and the amino groups of chitosan and also due to thermal cross-linking of NR during compression at 140°C. The presence of bound rubber and reacted chitosan in the blend supports the interfacial interaction between the phases in the blend and also thermal cross-linking.The compatibilising effect of maleic anhydride (MA) on NR/CS blends shows that there is better interfacial interaction between NR and CS in the presence of maleic anhydride. The overall improvement in properties of compatibilised blends suggests that MA can be used as an effective reactive compatibiliser for NR/CS blends. © Koninklijke Brill NV, Leiden, 2012