Ljerka Kratofil

Study of the Compatibilizer Effect on Blends Prepared from Waste Poly(ethylene-terephthalate) and High Density Polyethylene

Abstract In this work mechanical recycling of waste poly(ethylene-terephthalate) (PET) in the presence of high density polyethylene (HDPE) was studied. The fraction of HDPE in PET/HDPE blends was 3, 5, 6 and 10 wt.%. Isocyanate HI compatibilizer was first synthesized and then added to the blends at a fraction of 5 wt.%. Ethylene-propylene-diene masterbatch (EPDM-M) was prepared by mixing and added in fraction of 15, 30 and 50 wt.%. All PET/HDPE blends studied were characterized by scanning electron microscopy SEM, differential scanning calorimetry DSC and melt flow rate (MFR). Blends prepared with isocyanate HI compatibilizer were also studied by FTIR spectroscopy. Appearance of new vibrations in the FTIR spectra confirms that during the blending reactions between isocyanate HI compatibilizer and blend components appear. Results show that used compatibilizers significantly improved compatibility of polymers in studied blends. From the results it is obvious that immiscibility of PET and HDPE can be overcome.

Reactive Extrusion of SAN/EPDM blends

Abstract The blending of styrene-acrylonitrile copolymer (SAN) and three different types of ethylene-propylene-diene terpolymer (EPDM) by reactive extrusion was studied and the free radical initiators: 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane (Luperco 101 XL), 2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3 (Luperco 130 XL), α,α′-di(t-butylperoxy)diisopropyl-benzene (Peroximon F40) and 2,2-azo-di-(2-acetoxy)propane (Luazo AP) were used. Besides, structural characteristics of the obtained blends, some rheological and mechanical properties were also established. The rheological behavior was determined using rheometer and corotating extruder. Measurements of mechanical properties included: tensile strength, impact strength and elongation at break have been made. Blends were separated on its structural components SAN, EPDM, graft (EPDM-g-SAN) and gel content, which were further characterized by solution viscosimetry and IR spectrophotometry. The obtained results elucidate the reactions that occur during extrusion process. The dominant grafting reaction was observed in blends prepared by using a Peroximon F40 as an initiator also showing outstanding mechanical and processing characteristics.

New materials from degraded styrene-acrylonitrile and ethylene-propylene-diene copolymers

Abstract Polymer blends of styrene-acrylonitrile (SAN) and ethylene-propylenediene copolymer (EPDM) were prepared by casting films from chloroform solution. Their compositions were 95/5, 90/10 and 80/20, respectively. To simulate ageing, SAN/EPDM blends were degraded at 140°C for several different time intervals and the degree of degradation was followed by IR spectroscopy and by determination of molar masses. To recover thermally degraded SAN/EPDM blends, in situ polymerization by addition of styrene monomer was applied. Characterization of SAN and EPDM, graft copolymer and gel was carried out in order to reveal the polymerization process. Extractions of the polymers were made using solvents in a Soxhlet equipment: SAN in a mixture of acetone/ methanol, EPDM in hexane, graft copolymer in tetrahydrofuran, while the remaining part was considered as gel. Identification of extracted polymers has been conducted by IR spectroscopy. The presence of graft copolymer in the polymerization mixture proved the grafting reaction of polymer radicals. The highest content of graft copolymer was obtained for SAN/EPDM polymer blends that were exposed to thermal treatment for the longest time interval of 90 h.