Thermal stability,morphology, and X-ray diffraction studies of dynamically vulcanized natural rubber/chitosan blends

The thermal degradation behavior of cross-linked Natural Rubber/Chitosan (NR/CS) blends was studied by thermogravimetric analysis (TGA). Dicumyl peroxide (DCP) was selected as a cross-linking agent. Peroxide-cured NR/CS blends exhibit very good overall thermal properties. The activation energy of degradation was analyzed using the Horowitz–Metzger equation. Vulcanization of rubber phase in the blend increased the activation energy. From the activation energy values, it is found that among the series of the blend compositions, NR₈₅CS₁₅ blend vulcanized with 3 pphr DCP exhibits better thermal stability. Better adhesion between the two phases with the incorporation of DCP is achieved which results in an enhancement in the thermal stability. The DSC curve shows that, the T _g of chitosan in the blend increased to 242 °C by dynamic vulcanization. The morphology of the vulcanized blends was studied by scanning electron microscopy. More uniform distribution was exhibited by the vulcanization of NR phase in the blend. X-ray diffraction (XRD) study shows an enhancement in the crystallinity by vulcanization.