Preparation and some properties of deproteinized natural rubber
1997
Klinpituksa, P. | Wongboontarig, P. (Prince of Songkla Univ. Pattani Campus, Pattani (Thailand). Faculty of Science and Technology. Dept of Rubber Technology and Polymer Science)
Protein allergy to products made from natural rubber latex is widespread. A solution to this problem is to replace natural rubber by deproteinized natural rubber. This reserach is aimed at the preparation of deproteinized natural rubber from fresh NR latex clone RRIM 600 and determination of some of its properties. The preparation was carried out by digesting of fresh latex with alcalase enzyme of 0.2 phr, sodium dodecyl sulfate 0.4 percent w/v at pH 7.5, 37 deg C for hrs. The centrifugation speed of latex from digestion by enzyme at 6,000; 8,000, 10,000 and 12,000 rpm for 1, 2 and 3 times for a period 30 min each was studied. The nitrogen content in deproteinized natural rubber obtaining by centrifugation at 10,000 rpm, 3 times for a period of 30 min each decreased from 0.415 percent of the original fresh latex to 0.024 percent. The particle size distribution of deproteinized natural rubber latex was practically the same as that of original natural rubber latex, average around 0.5 micro m in diameter. Some properties of unvulcanized preparation from deproteinized natural rubber were compared with those from RRIM 600 and STR 5L. Deproteinized natural rubber showed lower ash content, viscosity, plasticity and water absorption. However, the vulcanisates of deproteinized natural rubber showed higher cure time and elongation at break while tensile strength, tear strength, modulus and hardness were lower than those of both rubbers.
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