Oriented Films from Recycled Poly(ethylene terephthalate)/Recycled High-Density Polyethylene Compatibilized Blends J. Morawiec, 1 N. P. Krasnikova, 1, * A. Galeski, 1 M. Pracella 2 1 Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Lodz, Poland 2 Centre of Studies on Multiphase and Biocompatible Macromolecular Materials, National Research Council, Pisa, 56100, Italy Received 25 April 2001; accepted 7 February 2002 Published online 28 August 2002 in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/app.11308 ABSTRACT: The process for the compatibilized blending of recycled poly(ethylene terephthalate) and recycled high- density polyethylene with ethylene/glycidyl methacrylate copolymer was enlarged to the scale of a pilot plant. The addition of a compatibilizer effectively reduced the size of dispersed inclusions with better bonding to the matrix. The optimum contents of the compatibilizer were found to be around 4 pph. The extrusion and orientation of films from the blend were developed on an industrial scale, and the structure and properties of the obtained films were charac- terized. The crystalline phase of poly(ethylene terephthalate) in oriented films assumed a strong texture resulting from the plane-strain state of the deformation of the films on the industrial machinery. The origin of the texture was mostly strain-induced crystallization. The chain segments in the amorphous phase were oriented along the machine direc- tion, but there was significant anisotropy of the chain pack- ing in the amorphous phase in the plane perpendicular to the drawing direction, the pseudohexagonal packing of chain fragments being in register over the whole film. Such a texture of an oriented amorphous phase of poly(ethylene terephthalate) is reported here for the first time. The nonori- ented and oriented films obtained with the industrial ma- chinery showed good mechanical properties, with strengths up to 120 MPa and elongations to break of 40%. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1486 –1496, 2002 Key words: blends; compatibilization; films; orientation; polyethylene (PE); recycling INTRODUCTION Success in recycling relies very much on the chemistry of the polymer involved and on the purity of the scrap. Polyethylene (PE), polypropylene, poly(ethylene terephthalate) (PET), poly(vinyl chloride), and poly- styrene are the most common scrap plastics. In the total volume of waste in Europe, plastics are 65% polyolefins. 1 In the countries of Central Europe, the percentage of polyolefins in waste is not different. PET constitutes 5 wt % of the plastic waste in Europe. 1 In Poland, 1.2 billion PET bottles in 2000 were used for soft drinks, and the amount is increased by 25% per year. 2 In principle, all of it could be recovered and recycled. It is estimated that in Central and Eastern Europe, the consumption of PET for packaging will grow 14% per year during the next 5 years, reaching a total of 800,000 tons in 2005. At present, the automated processes for the segre- gation of scrap material according to the polymer type have not been 100% correct; usually, a number of different polymers are collected. The successful recycling of PET relies on the process that ensures the separation of PET bottles from other scrap polymers, and then the bottles are processed by careful washing, cutting, and grain classification by size. 3,4 The process consists of no regranulation step, thereby avoiding additional degradation. Thorough drying followed by melt filtering and the addition of appropriate antioxidants leads to high-quality ex- truded products from recycled PET (R-PET). This pro- cedure is costly and not 100% efficient. Therefore, scrap polymers usually have poor mechanical proper- ties, which are the result of degradation during pro- cessing and the presence of large amounts of poly- meric and nonpolymeric inclusions. Because R-PET contains a mixture of polyolefins, whereas polyolefin recyclates are usually mixtures also containing PET, blending seems to be a good way of recycling without careful segregation. The crucial problem is that, when polymers are blended, many important properties are severely depressed because of the incompatibility of Correspondence to: A. Galeski (andgal@bilbo.cbmm.lodz.pl). *Permanent address: Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow, Russia. Contract grant sponsor: EU INCO-Copernicus; contract grant number: IC15 CT96 0731. Contract grant sponsor: Centre of Molecular and Macro- molecular Studies (Polish Academy of Sciences). Journal of Applied Polymer Science, Vol. 86, 1486 –1496 (2002) © 2002 Wiley Periodicals, Inc.