Properties of Natural Rubber Vulcanizates/Nanosilica Composites Prepared Based on the Method of In-situ Generation and Coagulation |
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Authors: | Yanfen Lin Anqiang Zhang Jiannan Sun Lianshi Wang |
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Institution: | Department of Polymer Material Science and Engineering , South China University of Technology , Guangzhou , China |
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Abstract: | Using the characteristics of silica sol dispersing well in water and easy formation of silica gel when the silica sol is heated, by mixing a system of concentrated natural rubber latex and silica sol, the silica sol can in-situ generate SiO2 particles when heated. After coagulation of the mixed system, natural rubber/nanosilica composites C(NR/nSiO2) were obtained. The composites C(NR/nSiO2) and their vulcanizates were studied using a rubber processing analyzer (RPA), dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM). The influence of silica contents on the C(NR/nSiO2) vulcanizates mechanical properties, cross-linking degree, Payne effect, dissipation factor (tanδ), and the particle size and dispersion of SiO2 in NR were investigated. The results obtained were compared with the NR/SiO2 composites based on traditional dry mixing of bale natural rubber and precipitated silica (white carbon black). The results showed that when using a sulfur curing system with a silica coupling agent (Si69) in C(NR/nSiO2), the vulcanizate had better mechanical properties, higher wet resistance, and lower rolling resistance than those without Si69. In the composites C(NR/nSiO2) and their vulcanizates, the SiO2 particles’ average grain diameter was 60 nm, and the good-dispersion of the in-situ generated SiO2 in the rubber matrix were a significant contribution to the satisfactory properties of C(NR/nSiO2) composites and their vulcanizates. |
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Keywords: | in-situ generation coagulation method natural rubber/silica composites silica sol vulcanizates |
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