Characterization And Properties Of Ultrafine Silica As A Filler In Natural Rubber Compounds
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Date
2011-06
Authors
Idrus, Siti Suhaida
Journal Title
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Publisher
Universiti Sains Malaysia
Abstract
In Malaysia, silica had been selling in crude way and part of it was being exported to overseas to be value added and yet Malaysia is importing the high quality silica for the local manufacturing industry consumption. Besides agglomeration problem, this imported precipitated silica was very expensive. Therefore, upgrading local silica in term of physical and chemical characteristics could be the best solution. In this study, there are two major parts involved, i.e. value adding of silica to become ultrafine silica via air classification and incorporation of ultrafine silica as a filler in SMR L grade natural rubber. Silica from local resources were upgraded by using 50 ATP-forced vortex air classifier. The fineness product obtained was 1.01 μm with span value of 0.83 when it was classified at 12 kg/h, 7000 rpm and 100 m³/h. The classification process was influenced by all the operational parameters. The degree of crystallinity of the classified product ranged from 68.44% to 87.41%. Three series of work had been carried out to investigate the incorporation of ultrafine silica as filler i.e. comparison of ultrafine silica and commercial silica, comparison of silanized ultrafine silica and untreated ultrafine silica and effect of differences shape of ultrafine silica. The results shows that the improvements in the characteristics of the ultrafine silica had shown better cure characteristics, tensile properties and rubber-filler interaction compared to commercial precipitated silica. The presence of silane coupling agents, bis [(3-triethoxysilylpropyl) tetra sulfide] (TESPT, or Si-69) had improved the adhesion between ultrafine silica and natural rubber matrix, consequently giving better properties compared to untreated ultrafine silica. Having irregular shape of ultrafine silica giving highest tensile properties compared to cubical shape and elongated shape. However, there is no significant trend when varying several of shapes in cure characteristic.
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Keywords
Ultrafine silica as a filler , in natural rubber compounds