MIXING SEQUENCE IN NATURAL RUBBER CONTAINING ORGANOCLAY AND NANO-CALCIUM CARBONATE TERNARY HYBRID NANOCOMPOSITES

摘要

Rubber nanocomposites containing one type of nanofiller are common and are widely established in the research field. In this study, natural rubber (NR) based ternary nanocomposites containing both calcium carbonate and organoclay have been-characterized on the basis of morphology, cure characteristics, and physico-mechanical behavior. Natural rubber nanocomposite samples containing modified silicate (Cloisite 15A) and also nano-carbonate calcium were prepared using a laboratory internal mixer. The effect of the mixing sequence on the morphology and mechanical properties of the samples was investigated. Based on results of morphology and mechanical properties, the dual fillers phase nanocomposites (hybrid nanocomposite) perform better in comparison with single filler phase nanocomposites. The reinforcing capability of nano-CaCO3 and organoclay in NR was characterized by means of cure rheometry, morphology, and mechanical properties. NR/single filler phase and two filler phase nanocomposites were prepared by simple melt mixing method. Concentration of nano-CaCO3 and organoclay in NR was 10 and 5 parts per one hundred parts of rubber by weight, respectively. The microstructure and homogeneity of the compounds was confirmed by studying the dispersion of nanoparticles in NR via X-ray diffraction and field emission scanning electron microscopy. A more pronounced effect was achieved by using dual filler based nanocomposites as compared with single filler phase nanocomposites. The obtained results reveal that hybrid nanocomposites have more adequate morphology, rheometery, and mechanical behaviors as well as swelling resistance. The effect of mixing sequence of fillers has been studied in detail. Simultaneous addition of the two nanofillers to the NR compound would lead to better nanocomposite properties compared with other mixing sequences. Also, the results show that the mixing sequence of these nanofillers in NR has little effect on the performance of the nanocomposite.