Organomodified kaolin as filler for natural rubber

Abstract

Organokaolin, through the incorporation of cationic hexadecyltrimethyl ammonium bromide in various concentrations (50%, 100% and 200% cation exchange capacity, CEC) into kaolin clay?s interlayer spaces have been prepared. This was characterized using XRD and FTIR to get information on sample structural composition and characteristic bonds on modification. These clays were further used as filler in natural rubber compounds with a semi-ultra; delayed action accelerator scheme. The X-ray diffraction analysis showed marginal increase in basal (d(001)) spacing of kaolin platelets from 4.01 to 4.90 nm. Changes in the clay?s molecular environment induced by ion-exchange process were followed by FTIR measurements revealing various CTAB+ influenced absorption peaks as modification progressed. Cure characteristics, scorch (ts2) and cure (t90) time of the organokaolin filled natural rubber composites was observed better than that of the 40 phr bulk kaolin across the CEC organophilization concentrations and filler loadings studied. Vulcanizate properties showed considerable increase in M100, M200, M300, TS, and elongation at break (%) indicating its potential as an organomodified filler. Hardness (IRHD) and abrasion resistance showed similar trend as tensile properties, with the incorporation of organoclay.