Surface modification of China clay to enhance reinforcing effect in rubber compounding

Abstract

This project reviews the surface chemistry of China clay (Kaolin) in the attempt of enhancing the reinforcing effect and the dispersion quality without silan1sation or amine addition. The polar chemistry of silica/silicate is resorted due to the fact that china clay (Rubber grade; processed at Boralesgamuwa refinery by Lanka Ceramic Limited) contains approximately 46% Sio2 and 36% Al2O3 by weight. China clay was oxinated to reduce the agglomeration due to the attraction between Gibsite to Silicate layers. Then treated with selected polar polymers in aqueous and non aqueous mediums to eliminate hydrophilic nature of clay which causes difficulty of achieving rapid wetting and dispersion in rubber and retarding effect on vulcanization rates of accelerated sulphur compounds. In addition to the above treatment methods, coarser particles of clay has been eliminated by incremental gravitational sedimentation and the suspension was subsequently flocculated with a polar polymer. Laboratory investigations of rubber compounds reveal the capability of reacting above polar polymers with silanol groups in china clay particles to promote wetting properties of rubber thereby enhance the dispersion quality,reinforcing effect and cure characteristics of sulfur cure systems when compared with respect to carbon black.(N-330)