Gamma radiation induced synthesis of poly(N-isopropylacrylamide) mediated by Reversible Addition-Fragmentation Chain Transfer (RAFT) process


KIRAÇ F. , GÜVEN O.

RADIATION PHYSICS AND CHEMISTRY, vol.112, pp.76-82, 2015 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 112
  • Publication Date: 2015
  • Doi Number: 10.1016/j.radphyschem.2015.03.013
  • Title of Journal : RADIATION PHYSICS AND CHEMISTRY
  • Page Numbers: pp.76-82

Abstract

Poly(N-isopropylacrylamide) (PNiPAAm) is synthesized by gamma radiation induced Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization. The monomer is polymerized in the presence of two different trithiocarbonate-based RAFT agents i.e., Cyanomethyldodecyltrithiocarbonate (CDTC) and 2-(Dodecylthiocarbonothioylthio)-2-methylpropionic acid (DMPA) in dimethylformamide (DMF) at room temperature under nitrogen atmosphere. Number-average molecular weights (M-n) and dispersities of the polymers were determined by Size Exclusion Chromatography (SEC). Dispersities (D) of the resulting polymers are narrow, i.e., D <= 1.18, indicating the occurrence of well-controlled polymerization via radiation induced RAFT process. %Conversion is determined by gravimetric method and also confirmed by Proton Nuclear Magnetic Resonance (H-1-NMR) Spectroscopy. By selecting proper [Monomer]/[RAFT] ratio and controlling conversion it is possible to synthesize PNiPAAm in the molecular weight range of 2400-72400 with extremely low molecular weight distributions with the anticipation of preparing corresponding size-controlled nanogels. The phase transition of PNiPAAm with low dispersity synthesized by RAFT is sharper than PNiPAAm synthesized by free radical polymerization. (C) 2015 Elsevier Ltd. All rights reserved.