By Asst. Prof. Dr. Sommai Pivsa
Award Silver Prize : Seoul International Invention Fair 2009 (SIIF 2009)
This research aimed to develop the natural rubber latex materials to substitute the utilization of PVC materials in a dip-molding process. We studied the preparation of prevulcanized latex having 2 kinds of additives; calcium carbonate (CaCO3) and clay. The amounts of additives were varied of 0, 5, 7.5, 10, 12.5 and 15 phr. The prevalcanized latex products were subjected to mechanical, electrical properties analysis as well as the dip-molding process ion product thickness. It was found that, the product contained 15 phr of clay showed the results of tensile strength, elongation at 300% modulus, tear strength and hardness of 20.12 Mpa, 739.02%, 2.2 Mpa 26.63 N/mm and 62.8 shore A, respectively. The crosslink density of product was 0.28 and the volume resistivity, surface resistivity and dielectric constant were 3.24 X 109 Ω/cm, 4.32 X 109 Ω and 3.10, respectively. The compound prevalcanized latex wad fabricated using dip-molding process with dipping time at 20, 30, 40, 50 and 60 seconds with repeating dipped of 1, 2, 3, 4 and 5 times. It was found that the dipping conditions of 4 times dipping of 50 seconds each dip and cured at 90oC for 30 min gave the product having thickness comparable with the PVC products.
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