view:24701 Last Update: 2018-10-20
Shabnam Mohajery, , Sohrab Rahmani and Ali Akbar Entezami|
Synthesis of functional polyethylene graft copolymers by nitroxide-mediated living radical polymerization
سنتز کوپلیمر پیوندی پلی اتیلن عاملدار از طریق پلیمریزاسیون رادیکالی زنده با حدواسط نیتروکسیدی
This paper describes a new method to prepare graft copolymers, such as polyethylene-g-polystyrene (PE-g-PS), with a relatively well-controlled reaction mechanism. The chemistry involves a transformation process from the metallocene copolymerization of ethylene and m,p-methylstyrene (m,p-MS) to nitroxide-mediated ‘‘living’’ free radical polymerization (LRFP) of styrene. The metallocene catalysis produces ethylene-co-m,p-methylstyrene (EMS) random copolymers. Next, 1-hydroxyl-2,2,6,6-tetramethylpiperidine (HO-TEMPO) was synthesized by the reduction of TEMPO with sodium ascorbate. The macroinitiator (EMS-TEMPO) was synthesized with the bromination reaction of EMS, and the following nucleofilic reaction with this functional nitroxyl compound. The resulting macroinitiator (EMS-TEMPO) for LRFP was then heated in the presence of styrene to form graft copolymer. DSC, 1H-NMR, FTIR spectroscopy were employed to investigate the structure of the polymers. The results of Molau test showed that PE-g-PS could be a potential good compatilizer.