Preparation of ABCBA-type block copolymers by use of macro-initiators containing peroxy and azo groups |
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Authors: | Baki Hazer,Alipa a Ayas,Necati Be irli,Necdet Saltek,Bahattin M. Baysal |
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Affiliation: | Baki Hazer,Alipaşa Ayas,Necati Beşirli,Necdet Saltek,Bahattin M. Baysal |
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Abstract: | Some new macroinitiators ( 5 ) containing azo and peroxy groups were synthesized by transformation of esters of poly(ethylene glycol) ( 1 ) (PEG) of different molecular weight with hydroxyl end groups and an azo group in the middle into the corresponding polymers with tert-butylperoxycarbonyl end groups by reaction with terephthaloyl chloride and subsequently with tert-butyl hydroporoxide. Decomposition in the presence of styrene at 60°C or with 3,6,9-triazaun-decane-1,11-diamine in presence of methyl methacrylate gave the corresponding ABA block copolymer 6 and the ABBA block copolymer 7 , respectively. Both block copolymers were used as polymeric initiators. The ABCBA block copolymer 8 was synthesized from 6 and methyl methacrylate or from 7 and styrene by thermally induced polymerization at 80°C. The resulting block copolymers were separated from the homopolymers by selective solvent extraction and characterized by spectroscopic and fractional precipitation methods. |
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