Structure and performance of reclaimed rubber obtained by different methods

Four different reclaiming methods involving important reclaiming factors such as temperature, shear force, and atmosphere were used to reclaim ground tire rubber. The structure and performance of the reclaimed rubber were investigated. The reclaimed samples were all found to be mixtures of three parts: the sol part, a loosely crosslinked gel part, and low molecular substances. For a reclaimed product to have both good processability and mechanical properties, the ideal structure should be that the sol fraction and its molecular weight (Mn) are as high as possible. However, the high sol fraction and high Mn cannot be reached at the same time because of the nonselective scission of the main chain and crosslink bonds. Thus, for a reclaimed rubber to have high quality, the presence of some amount of gel fraction is essential. Our preliminary results showed that the recommended reclaiming method would be a process under oxygen-free atmosphere, without severe shear force, and at relative low temperature. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013