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Synthesis and Characterization of Poly( N ‐isopropylacrylamide) and Poly(vinyl acetate) Diblock Copolymers via MADIX Process
Author(s) -
Özgüç Çimen,
Helvacıoğlu Ekmel,
Nugay Nihan,
Nugay Turgut
Publication year - 2013
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.201100105
Subject(s) - copolymer , vinyl acetate , amphiphile , polymer chemistry , dynamic light scattering , micelle , materials science , chain transfer , raft , critical micelle concentration , chemistry , polymer , radical polymerization , organic chemistry , nanoparticle , nanotechnology , aqueous solution , composite material
Abstract The synthesis of diblock copolymers of poly( N ‐isopropylacrylamide) (PNIPAM) and poly(vinyl acetate) (PVAc) was performed by macromolecular design via interchange of xanthates (MADIX) process. Following the preparation of methyl (isopropoxycarbonothioyl) sulfanyl acetate (MIPCTSA) as chain transfer agent, it was reacted with vinyl acetate to obtain PVAc macro‐chain transfer agent. Then, block copolymerization was completed by successive addition of N ‐isopropylacrylamide (NIPAM). 1 H NMR spectroscopy confirmed the presence of both blocks in the copolymer structure, with the expected composition based on the feed ratio. Size Exclusion Chromatography (SEC) was used to investigate the relative values of molecular characteristics. Only 20% of PVAc was converted to block copolymer. The resultant block copolymer structures were further examined in terms of their morphologies as well as critical micelle concentration (CMC) by using ESEM and Fluorescence Excitation Spectroscopic techniques, respectively. Morphological characterization confirmed amphiphilic block copolymer formation with the existence of mainly ca. 100 nm well distributed micelles. The thermo responsive amphiphilic behavior of the block copolymer solutions were followed by Dynamic Light Scattering (DLS) technique.