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Recycled poly(ethylene terephthalate) (R-PET)/high-density polyethylene (HDPE)/glycidyl methacrylate grafted poly(ethylene-octene) (mPOE) blends, in which the binary (HDPE/mPOE) dispersed phase was of a HDPE core-mPOE shell structure, were prepared. For this purpose, HDPE-g-mPOE graft copolymers were prepared in HDPE/mPOE blends via reactive extrusion with the presence of the free radical initiator dicumyl peroxide (DCP). Then, R-PET was blended with the HDPE/mPOE blends by melt extrusion. The effect of the DCP and mPOE content in the HDPE/mPOE blends on the phase morphology and mechanical properties of the R-PET/HDPE/mPOE blends were studied systematically. It was found that the blends containing reactive compatibilizer exhibited the encapsulation of the HDPE by the mPOE, forming core–shell particles dispersed phase morphology. The graft chains of HDPE-g-mPOE-g-PET formed by the in situ reaction between R-PET and mPOE phases reduced the interfacial tension. Consequently, the dispersed phase morphology was observed to form smaller diameter core–shell particles. The resultant blends exhibited an effect on both the thermal and mechanical properties. Differential scanning calorimetric analysis showed the dispersed phase particles could act as a nucleating agent in the R-PET matrix to improve the crystallization temperature, while the graft copolymers formed in the compatibilized R-PET/HDPE/mPOE blend decreased the nucleation activity. Notched Charpy impact strength and elongation at break of the R-PET were improved by forming the core–shell particles dispersed phase morphology. [ABSTRACT FROM AUTHOR]

High toughness recycled poly(ethylene terephthalate) (R-PET)/poly(ethylene-octene) (POE) blends were prepa scanning electron microscopy red by adding glycidyl methacrylate grafted poly(ethylene-octene) (mPOE) as reactive compatibilizer. Evidence for reaction between the carboxyl or hydroxyl end groups of R-PET and the epoxy groups of mPOE under the conditions of processing to form graft copolymers (PET-g-mPOE) is presented. Effects of compatibilizer on morphology and mechanical and thermal properties of the blends were evaluated systematically. The results showed that dispersed phase particle size decreased with increasing mPOE content until the critical compatibilizer concentration (5 wt%) was reached. Notched Charpy impact strength and elongation at break were improved greatly by the addition of compatibilizer. Differential scanning calorimetry (DSC) analysis showed POE could act as a nucleating agent in the R-PET matrix to improve the crystallization temperature, while the graft copolymers formed in compatibilized R-PET/POE blends decreased the nucleation activity. [ABSTRACT FROM AUTHOR]

Abstract: Polymeric methylene diphenyl diisocyanate (PMDI) was added as chain extender to a blend of recycled poly(ethylene terephthalate) (R-PET) and linear low density polyethylene (LLDPE) with compatibilizer of maleic anhydride-grafted poly(styrene–ethylene/butadiene–styrene) (SEBS-g-MA). Hydroxyl end groups of PET can react with both isocyanate groups of PMDI and maleic anhydride groups of SEBS-g-MA, which are competing reactions during reactive extrusion. The compatibility and properties of the blends with various contents of PMDI were systemically evaluated and investigated. WAXD results and SEM observations indicated that chain extension inhibits the reaction between PET and SEBS-g-MA. As the PMDI content increased, the morphology of dispersed phase changed from droplet dispersion to rodlike shape and then to an irregular structure. The DSC results showed that the crystallinity of PET decreased in the presence of PMDI, and the glass transition temperature (T g) of PET increased with addition of 0–0.7w% PMDI. The impact strength of the blend with 1.1w% PMDI increased by 120% with respect to the blend without PMDI, accompanied by only an 8% tensile strength decrease. It was demonstrated that the chain extension of PET with PMDI in R-PET/LLDPE/SEBS-g-MA blends not only decreased the compatibilization effect of SEBS-g-MA but also hindered the crystallization of PET. [Copyright &y& Elsevier]