Nitroxide mediated and atom transfer radical graft polymerization of atactic polymers onto syndiotactic polystyrene

• Autor(a) principal: Abbasian,M.
• Data de Publicação: 2012
• Outros Autores: Shoja,S. Esmaeily
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Brazilian Journal of Chemical Engineering
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0104-66322012000200009
• topic: Syndiotactic polystyrene; Graft copolymer; Poly(methyl methacrylate); Atom transfer radical polymerization; Nitroxide-mediated 'living' free radical polymerization; TEMPO

'Living' radical graft polymerization was employed to prepare graft copolymers with nitroxide-mediated arylated syndiotactic polystyrene as the backbone and polystyrene (PS), poly(p-methylstyrene) (PMS) and poly(methylmethacrylate) (PMMA) as branches. A two-stage process has been developed to synthesize the macroinitiator. First, syndiotactic polystyrene (sPS) was modified by the Friedel-Crafts reaction to introduce chlorine; second, the chlorine groups were converted to nitroxide mediated groups by coupling with 1-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO-OH). The resulting macroinitiator (sPS-TEMPO) for 'living' free radical polymerization was then heated in the presence of styrene and p-methylstyrene to form graft and block copolymers. We used the obtained copolymer and N-bromosuccinimide as brominating agent to achieve polymers with bromine groups. This brominated copolymer was used as a macroinitiator for polymerizing methyl methacrylate in the presence of the CuBr/bpy catalyst system. The formation of the graft and block copolymers was confirmed by DSC, ¹H NMR and FTIR spectroscopy. This approach using macroinitiators is an effective method for the preparation of new materials.