Enhancement of processability of ground tire rubber powder and LDPE blends.pdf

ORIGINAL PAPER Enhancement of processability and foamability of ground tire rubber powder and LDPE blends through solid state shear milling Jian Zhu Xinxing Zhang Mei Liang Canhui Lu Received: 12 January 2010 /Accepted: 28 April 2010 /Published online: 14 May 2010 # Springer Science+Business Media B.V. 2010 Abstract The foamed composites made from low-density polyethylene(LDPE) and ground tire rubber(GTR) powder using azodicarbonamide as chemical blowing agent have been investigated. Solid state shear milling was used to enhance the processability and foamability of LDPE/ GTR blends by a pan-mill type mechanochemical reactor. First the blends of LDPE/GTR were prepared by co- milling, then the samples were melt-mixed in a Bra- bender Plasti-Corder, saturated with blowing agent, crosslinking agent and blowing co-agent, and finally the saturated specimens were expanded during the pressure- quench process. The results indicated that the mechanical properties of the LDPE/GRT foamed composites were improved, and the blends of co-milled GTR and LDPE powder showing better processability and foamability than those obtained in a conventional melt-mixing manner, as indicated by the rheological and morphological studies. Keywords Ground tire rubber . Low-density polyethylene . Compatibility . Recycling . Foaming agent Introduction Nowadays, with the increasing in the number of automo- biles, waste tires become a significant problem to our society. Several methods for waste tires treatment such as combustion, burying underground, and recycling have been developed to solve this problem [1–6]. Among them, recycling is the most attractive [7, 8]. The difficulty in recycling waste tires is that the scrap tire rubber is a crosslinked polymer and hard to melt and to process, so some chemical additive should be added to enhance processability [9, 10]. So far, devulcanization is the better method for recycling waste tire rubber. Many methods such as microwave [11], ultrasound [12], a