Study On Natural Rubber Latex Modified By Polyorganosiloxane

The natural rubber latex modified by polyorganosiloxane was produced by the methods of grafting copolymerization and blending with the solubilizing agent taking part in the reaction .The effect of the kinds and dosage of coupling agent, NR latex concentration , dosage of initiator .reaction temperature , reaction time and the kinds and dosage of organosilixane to the monomers conversion and monomers graft percent in graft copolymerization reaction had been studied . The suitable technical methods of modification were determined by using the statistical analysis of orthogonal experiment . colloid properties, film structure and rubber film's mechanical properties of the natural rubber latex modified by polyorganosiloxane were tested.The results showed that the monomers conversion and monomers graft rate of VD4 was higher than 04 in graft copolymerization reaction; A-171 was the best coupling agent among KH-550 , KH-570 , A-151 and A-171 .because the highest graft percent of organosilixane monomer was attained by using it; the monomers conversion and the graft rate was increased significantly by increasing the ratio of D4 or VD4/NR , increasing the reaction time and increasing reaction temperature; the condign technical methods of modification of organosilixane grafting onto NR was attained: the NR latex concentration was 50% , reaction temperature was 55 癈 , reaction time was 4h , the dosage of A-171 was 1.2%( occupying rubber's quality percent, the same to the undersides ), the dosage of organosilixane was 15% and the dosage of initiator was 1.0%; modified latex had the higher stability, thegrafted latex film and vulcanized latex film had the better physical mechanicsproperties and the better resistance to solvent than blending latex film and vulcanized latex film. Polyorganosiloxane definitely grafted onto NR .which was proved by IR. Besides, modified NR latex was studied by TG DTG DSC and DMA. DMA proved that the organosilixane in grafted modification had the better compatibility with NR than the organosilixane in blending modification with NR; and the compatibility between organosilixane and NR was increased remarkably if some compatibilizer was added in blending latex; and the better bounce impact elasticity and antifatigue property were attained by the grafted latex vulcanized film. TG DTG and DSC proved that the natural rubber vulcanized latex film modified by polyorganosiloxane using the methods of grafty copolymerization had the better heat resistence than blending and NR vulcanized latex film; the heat resistence was enhanced by modifying NR.