Study On Natural Rubber Composites Prepared By Latex Co-Agglomeration

With the rapid development of the global rubber industry, the crisis of resources and peoples’increasingly awareness of environmental protection, it is necessary for rubber industry to discover a kind of green-filler with pollution-free, low cost, a wide source and good reinforcement effect, and develop a processing technology, which is simple and environment friendly, to fabricate high-performance rubber products. In this paper, effects of different coagulants and coagulation processes on properties of the natural rubber and its vulcanizates were studied based on the natural rubber latex, and at the same time, both natural rubber/lignin composites and natural rubber/silica composites were prepared by the latex co-agglomeration. The dispersion of fillers in both dispersion and rubber matrix were inspected by some advanced equipments, just as Scanning Electron Microscopy(SEM), Transmission Electron Microscopy(TEM), Laser Particle size Distribution Tester, Phase-contrast Microscopy and FT-IR; the mechanical properties and dynamic mechanical properties of natural rubber composites were characterized by Electronic Tensile Machine and Rubber Processing Analyzer RPA2000. The result showed that:(l)Different coagulants and coagulation processes had different effects on the coagulation effect of natural rubber latex. It is found that, CaC12alcohol solution had the best coagulation effect compared with CaC12solution and Formic acid, and the most suitable concentration of CaC12in alcohol solution was20%, which was beneficial for both coagulation of latex and comprehensive performances of the rubber. At the same time, it is also found that the process in which coagulant was added into latex had good coagulation effects on latex and the natural rubber had better comprehensive performances than that by the process in which latex was added into coagulant.(2)The natural rubber/lignin composites were prepared by latex co-agglomeration. The result showed that the Mooney viscosity (ML(3+4)120℃) of the composites gradually increased with the increase of lignin content, reaching the highest point when the lignin content was20phr, the ML increased as well as the t。9o, while the MH and tsi reduced. The dispersion effect of carbon black was bad and the composites had poor processing safety, wear resistance and aging resistance. The modulus of the vulcanizates decreased. The tensile strength and tear strength of the vulcanizates could be improved when the lignin was added within20phr. (3) The natural rubber/white carbon black composites were successfully prepared by latex co-agglomeration, which solved the poor dispersion of silica in natural rubber matrix. The result indicated that the dispersion had good properties, which was treated by either T25high-speed dispersion machine or the high-pressure homogenizer. With the time prolonged, the mean particle size of dispersion decreased and the particle size distribution became narrow, as a result of which the dispersion of white carbon black in rubber matrix was well improved. The comprehensive mechanical properties of vulcanizates made by this method are better than that made by traditional mechanical mixing. The white carbon black particles made by in-stu generation had small size and dispersed evenly in rubber matrix, and if added into the natural rubber, they could greatly improve the mechanical and dynamic mechanical properties of natural rubber/white carbon black composites.