Copolymerization of 2,2,3,3,4,4,4-heptafluorobutyl acrylate with butyl acrylate via RAFT polymerization
Copolymers of fluoroacrylates have interesting properties like excellent resistance to chemicals, oils and fuels, high thermal stability and high hydrophobicity. This investigation reports the copolymerization of 2,2,3,3,4,4,4-heptafluorobutyl acrylate (HFBA) and butyl acrylate (BA), i.e. the two monomers having semi-fluorinated and non-fluorinated pendant groups of equal length (C-4) via reversible addition-fragmentation chain transfer (RAFT) polymerization. The copolymers had controlled molecular weights and narrow polydispersity indices. The copolymer compositions were determined by H-1 NMR spectroscopy. The reactivity ratios of HFBA and butyl acrylate BA were calculated by using three different models viz., Finemann-Ross (FR), inverted Finemann-Ross (IFR) and Kelen-Tudos (KT). The reactivity ratios were determined as r(HFBA) = 0.65 and r(BA) = 0.83, by the FR method. Thermal stability and glass transition temperature of the copolymers increased with the increase in HFBA content. The water contact angle (WCA) of the copolymers increased with increase in HFBA content indicating increasing hydrophobicity of the copolymer having higher HFBA content. (C) 2014 Published by Elsevier B.V.