____________________ * Corresponding author: 292, rue Saint Martin - 75141 Paris Cedex 03 – France – Tel.: + 33(0)1 40 27 27 85 alain.guinault@cnam.fr THERMOMECHANICAL PROPERTIES OF ABS/PA AND ABS/PC BLENDS A.Guinault 1* , C.Sollogoub 1 1 CNAM – Laboratoire des Matériaux Industriels Polymères ABSTRACT: The significant increase of Waste Electric and Electronic Equipment (WEEE) has led to an important research in upgrading recycled engineering plastics by means of a blending technique. Classical twin-screw extrusion is compared to a new blending technique, where two polymers are combined together and then flow in several static mixers. This technique allows to obtain different morphologies of compatibilized ABS/PA or ABS/PC blends and the aim of this work is to evaluate the corresponding thermomechanical properties. Experimental results demonstrate in particular that fibrilar morphology is obtained with the new blending technique (only with ABS/PA blends), which could lead to a mechanical enhancement if the adhesion between ABS and PA is optimized. KEYWORDS: WEEE recycling, mechanical recycling, blending technique, ABS/PA and ABS/PC blends 1 INTRODUCTION In the last years, electric and electronics industry has become one of the big consumers of engineering plastics, generating simultaneously a big amount of wastes coming from these materials (WEEE). One of the most used plastic in engineering applications is ABS, acrylonitrile – butadiene – styrene copolymer. This polymer, characterized by easy processability, relatively low cost and high impact and chemical resistance, widely appears in parts of computers or TV equipments. The recycling of ABS is rendered difficult because of the oxidative degradation of the butadiene rubber phase during service time, deteriorating its mechanical properties [1]. An interesting way proposed to recycle ABS coming from electrical and electronic equipments is to use blending techniques, in order to combine ABS with polymers presenting a good mechanical and thermal resistance, like PC (Polycarbonate) [1,2] or PA (Polyamide) [3]. Many studies have been reported in the literature on virgin ABS/PC [4,5] or ABS/PA [6,7,8] polymer blends, focusing on the compatibilization question or studying the rheological, mechanical, thermal and morphological properties of these blends. It is even possible to find commercial blends of these materials (see for example CYCOLOY ® , an ABS/PC blend commercialized by GE Plastics). Still, from an economical point of view, it would be beneficial to use for these blends, recycled PC or PA, coming from urban wastes. It appears that we can easily find PC from the recycling of Compact Discs and PA from automotive wastes. The purpose of our study is to investigate the possibilities of preparing blends of recycled ABS with recycled PC or PA, presenting high thermomechanical performance. In this paper, as a first investigation, we restrict our study on blends with virgin products. A new blending technique is used, where two polymers are combined by coextrusion and then flow through static mixers. A previous study [9] has shown that this blending technique offers the possibility to better control the blend morphology, which has impact on thermomechanical properties. The results obtained on blends prepared with this blending technique are compared with blends produced with an usual twin- screw extruder. 2 MATERIALS The virgin materials are commercial grades, chosen in order to have the same initial properties as the recycled materials. Terluran ABS GP 22 (BASF) is a very common product used for computer monitors. Technyl PA C206 (Rhodia) is a rather low molecular mass injection molding grade of polyamide 6 without glass fibers. Lexan PC 121R (GE plastics) is a high fluidity polymer (MW of 33050 g/mol) used to fabricate CD-ROMs. Table 1 indicates the different compatibilizers suggested by the literature as effective compatibilizers for ABS/PA blends and used in our study. On the other hand, no compatibilizer is needed for ABS/PC blends, since the two polymers used in our study present a rather good affinity.