engleski

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

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.

styrene-acrylonitrile; EPDM; polymer blends; degradation

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