Controlled radical polymerization of N-isopropylacrylamide initiated by photofunctional 2-(N,N-diethyldithiocarbamyl)isobutyric acid sodium salt in aqueous medium

• Published in: Journal of applied polymer science 2004-03, Vol.91 (5), p.3233-3238
• Main Authors: Ishizu, Koji, Khan, Ruhul A., Furukawa, Taiichi, Furo, Masahito
• Format: Article
• Language: English
• Subjects: Applied sciences; block copolymer; controlled radical polymerization; Exact sciences and technology; NIPAAm; Physicochemistry of polymers; Polymer industry, paints, wood; Technology of polymers; water-soluble initiator
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.13493

Photopolymerizations of N‐isopropylacrylamide (NIPAAm) were carried out in water, initiated by 2‐(N,N‐diethyldithiocarbamyl)isobutyric acid sodium salt (DTCA‐Na) as water‐soluble initiator under UV irradiation. The first‐order time‐conversion plots showed slowly decreasing slopes indicating a slow decrease of the active radical concentration. The number‐average molecular weight (Mn) of the obtained poly(N‐isopropylacrylamide) (PNIPAAm) increased in direct proportion, roughly, to monomer conversion. Until ca. 60% of conversion, the polydispersity was relatively narrow (ca. 1.6). 1‐Vinyl‐2‐pyrrolidone (VP) could also be polymerized in living fashion with such PNIPAAm precursor as a macroinitiator, because PNIPAAm exhibited dithiocarbamate (DC) groups at terminal ends. It was concluded that the polymerization of NIPAAm proceeded via a controlled radical mechanism in the range ∼60% of conversion. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3233–3238, 2004