POLYMER TESTING Polymer Testing 27 (2008) 321–329 Material Properties Preparation and characterization of polypropylene/waste tyre dust blends with addition of DCP and HVA-2 (PP/WTD P-HVA2 ) M. Awang, H. Ismail à School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Nibong Tebal, 14300 Penang, Malaysia Received 11 October 2007; accepted 5 December 2007 Abstract Preparation of polypropylene (PP)/waste tyre dust (WTD) blends with addition of dicumyl peroxide (DCP) and N,N 0 -m- phenylenebismaleimide (HVA-2) (PP/WTD P-HVA2 ) was described. The blends were characterized based on their tensile properties, swelling resistance and morphology, as well as thermal properties. The results reveal that the presence of both chemicals in PP/WTD P-HVA2 blends brought about noticeable improvements in tensile properties, swelling resistance and interfacial adhesion. The thermal stability was also improved, indicating existence of some chemical interaction between WTD and the PP matrix in the presence of both DCP and HVA-2 during processing. The results imply that both chemicals had great influences on WTD destabilization, leading to the enlargement and intensification of the copolymer formation and, hence, improved the interfacial adhesion between WTD and the PP matrix. A competing reaction mechanism that may contribute to the property enhancement of PP/WTD P-HVA2 blends was proposed. r 2008 Published by Elsevier Ltd. Keywords: Polypropylene; Waste tyre dust; DCP; HVA-2; Properties 1. Introduction A continuous accumulation of the scrap tires worldwide is an acknowledged threat to public health as well as to the environment [1]. Scrap tires will be unremittingly available and abundant as long as today’s high requirement for the automo- biles persists. Although several applications of scrap tyres have been reported [2,3], the present scrap tyre accumulation seems to demand more extensive research activities and broader applications of scrap tyres aiming at considerably reducing their volume. At present, two approaches have been practiced to trim down the accumulation of the scrap tyres [2]: (a) recycle or reuse and (b) reclaim rubber raw materials by various processes. Whilst reusing scrap tyres offers the best value recovery, converting them to energy proffers about 40% recovery [4]. Although a variety of rubber reclaiming processes are on hand, using scrap tyre rubber for products entails further treatments to make it compatible and viable for particular applications. For instance, employing different vulcanization agents imparted a significant influence on the properties of rubber/ reclaimed rubber blends [5]. Besides type of vulcanization agents, modification of tyre rubber by means of thermo-mechanical processes and adopting the technique of dynamic vulcanization ARTICLE IN PRESS www.elsevier.com/locate/polytest 0142-9418/$ - see front matter r 2008 Published by Elsevier Ltd. doi:10.1016/j.polymertesting.2007.12.001 à Corresponding author. Tel.: +60 45 996 113; fax: +60 45 941 011. E-mail address: hanafi@eng.usm.my (H. Ismail).