Thermal Behavior of Vulcanized Deproteinzed Natural Rubber Nano-composites

Thermal behavior of vulcanized depropteinized nano-composite were investigated in order to apply the DPNR latex as non-allergy. Removal of proteins from natural rubber was made by incubation of high ammonium natural rubber latex (HA-NR) with urea 0.1 wt% for 1 hour in the presence of surfactant at room temperature (DPNR). The nitrogen content of the DPNR was reduced to 0.05 wt%, which was lower than 0.45 wt% of HA-NR under the test condition. The reduction of protein content can be confirmed by observation a chemical structure through FT-IR technique. It is suggesting that the urea treatment is an effective method to remove protein from rubber latex. Amount of water soluble protein was observed through modified lowry method. It was found that the water soluble protein contented after incubation the HA-NR latex with urea was reduced from 4,245 μg/g to 15 μg/g. DPNR composite was prepared by incorporated nano-calcium carbonate (Nano-CaCO3) at 1 - 4 wt% into pre-vulcanized DPNR latex. Then, physical properties of the DPNR latex were investigated. The thermal properties of DPNR was investigated through the dynamic mechanical thermal analyzer and oxidation thermal aging. It was found that the corporation of nano-CaCO3 in DPNR latex could improve thermal and mechanical properties of the rubber. The results showed that the loss tangent (tanδ) was found to shift to lower temperature.