Compatibilization of Regenerated Low Density Polyethylene/Poly(vinyl chloride) Blends Soumia-Amina Kabdi, Naima Belhaneche-Bensemra Ecole Nationale Polytechnique, BP 182 El-Harrach, Algiers, Algeria Received 11 July 2007; accepted 13 October 2007 DOI 10.1002/app.28175 Published online 30 July 2008 in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: The aim of this work is to study the valori- zation of regenerated low density polyethylene (rLDPE) by blending with PVC in the presence of chlorinated polyethyl- ene (CPE) as compatibilizer. For this purpose, four rLDPE samples coming from neat or dirty wastes were used. They were obtained after milling, washing, and extrusion in a conventional recycling plant. They were first characterized in terms of physicochemical (density, melt flow index, water absorption, and level of oxidation by Fourier transform infrared spectroscopy) and mechanical (tensile and shore D hardness) properties. The effect of the ratio of PVC on these physical and mechanical properties was then investigated. These binary blends exhibited lower properties than those of the separated polymers. The addition of CPE to the binary blend with weight proportion of 50/50 leads to a substantial improvement of the considered properties which is due to a better interfacial adhesion between rLDPE and PVC as evi- denced by the analysis of the morphology of the blends by scanning electron microscopy. Ó 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110: 1750–1755, 2008 Key words: PVC; regenerated LDPE; blends; compatibili- zation; CPE; physicochemical properties; mechanical prop- erties INTRODUCTION Polyethylene (PE) and poly (vinyl chloride) (PVC) are the highest volume thermoplastics consumed in the world, constituting the dominant components of plastics wastes. As it is well known, PVC/PE blends are immiscible, giving rise to a phase-separated system with a very low degree of adhesion between components. 1 This lack of adhesion causes poor mechanical properties which limits the practical use of these blends. The use of a third polymer to ‘‘compatibilize’’ the blend and to obtain better mechanical properties is a key technology to obtain polymer blends with desirable properties. Many studies have been done on the compatibilization of this pair of polymers. 2–5 It was found that small amounts of chlorinated polyethylene (CPE) increases both ductility and tensile strength of PVC/PE blends. 2 Different rheological techniques were used to elucidate the role played by block and random CPEs in the rhe- ology of practical devoted HDPE/PVC/CPE systems. 5 The morphology and mechanical properties of PVC/ PE blends were also modified by adding butadiene rubber (BR) into the blend. This was attributed to the fact that BR can increase the melt viscosity of the PE- rich phase, and hence, decrease the viscosity ratio between the PVC-rich phase and PE-rich phase. 3 On the other hand, a compatibilization-crosslinking syner- gism technique was proposed to improve the mechan- ical properties of PVC and PE. 4 A compatibilizer can promote the phase dispersion of PVC and PE and their interfacial adhesion. Then, the probability of a crosslinking agent existing at the interface will increase and more cocrosslinked products will be formed. Therefore, compatibilization and crosslinking are both exerted sufficiently. It was found that BR or styrene- butadiene rubber (SBR) and the crosslinking agent dicumyl peroxide (DCP) have a good synergism in the improvement of the mechanical properties of incom- patible PVC/LDPE blends. 4 The objective of this work is to recycle regenerated LDPE in the form of blends with PVC in the pres- ence of CPE as compatibilizer. The latter is a com- monly used impact modifier of PVC and its compati- bility depends on the chlorine content and the distri- bution of the chlorine atoms on the PE backbone. 6 CPE with 36% chlorine is the optimum composition for obtaining the necessary features of impact, proc- essing and strength 3,7–9 and it is used in this work as the third component of rLDPE/PVC blends. EXPERIMENTAL Materials Four regenerated LDPE coming from different sour- ces (Table I) and obtained after milling, washing, Correspondence to: Belhaneche-Bensemra Naima (nbelha- neche@yahoo.fr). Journal of Applied Polymer Science, Vol. 110, 1750–1755 (2008) V V C 2008 Wiley Periodicals, Inc.