The Study Of Organic Silicon Modified Natural Rubber Latex And Its Film-Forming Properties

Natural rubber, as a renewable resource, is widely used in the field of medical products for its excellent properties, such as medical tube, gloves, etc. However, the natural rubber has poor performances on solvent resistance, oxidation resistance, thermostability and UV resistance, for its non-polar structure and unstable C=C bond. Moreover, protein is contained in natural rubber as a main ingredient, which would increase moisture absorption and cause mildew. These shortcomings limited the applications of natural rubber in many fields.Organic silicon is considered to be applied in the modification of the natural rubber for its hydrophobicity, low surface tension, moisture resistance and ventilation property. Three different modification methods were studied by utilizing the difference of the molecular structure and polarity between natural rubber latex and organic silicon. First, organic silicon emulsion with positive charges was synthesized through composite cationic emulsion polymerization, and then blended with the natural rubber latex. The organic silicon cationic emulsion could combine with natural rubber latex with negative charge as a heterocoagulation system by electrostatic interaction. Second, the organic silicon with vinyl double bond was grafted onto the natural rubber latex by using coupling agent. Third, the organic silicon with amino was grafted with polyurethane by coupling agent, and then the organic silicon-grafted polyurethane was blended with natural rubber latex. All these three different modification methods were made a comparison on mechanical properties, solvent resistance, water resistance, surface morphology of the modified natural rubber films.The results showed that all the three methods could increase the mechanical properties, solvent resistance, water resistance, surface morphology of the modified natural rubber films. The blend modification of organic silicon exhibited better on water resistance of the natural rubber films. The graft modification of organic silicon had a greater effect on solvent resistance and surface morphology of the films. The blend modification of organic silicon-grafted polyurethane had a more excellent performance on mechanical properties of the natural rubber films. Thus, the modified natural rubber has a wider potential application in the industrial products, daily necessities by the three different modification methods.