Chiang Mai Journal of Science

Kinetic Studies of the Photopolymerisation of Acrylamide in Aqueous Solution: Effects of Bromoformas a Chain Transfer Agent

Paper Type	Contributed Paper
Title	Kinetic Studies of the Photopolymerisation of Acrylamide in Aqueous Solution: Effects of Bromoformas a Chain Transfer Agent
Author	Kamonchanok Thananukul[a], Juraiporn Porkaew [b], Patchara Punyamoonwongsa [a], Robert Molloy*[b,c]
Email	robert.m@cmu.ac.th
Abstract:  The effects of adding bromoform (CHBr3) as a potential chain transfer agent in the photopolymerisation of acrylamide (AM) in aqueous solution have been studied both in terms of influencing the rate of polymerisation and the molecular weight of the polyacrylamide (PAM) formed.  Using 4,4´-azo-bis(4-cyanopentanoic acid) (ACPA) as photoinitiator, two different CHBr3 concentrations as chain transfer agent were compared: 0.5 and 2.0 mol % (relative to AM), the higher of which was determined by the limit of CHBr3 water solubility.  The results showed that CHBr3 was an effective chain transfer agent that could regulate the molecular weight of the PAM formed without seriously affecting the polymerisation rate.  It is concluded that chain transfer to CHBr3occurs by both Br and H atom transfer although Br transfer is the more favoured due to the weaker C‒Br bond.  Furthermore, Br transfer leads to Br-terminated chains in which the terminal C–Br bond can re-dissociate leading to re-initiation and re-propagation of the same chain, thereby maintaining the polymerisation rate.  Continuing studies into how this mechanism can be exploited in order to synthesize water-soluble block copolymers of potential biomedical importance are currently in progress.
Start & End Page	1352 - 1360
Received Date	2013-06-17
Revised Date
Accepted Date	2013-08-10
Full Text	Download
Keyword	Acrylamide, polyacrylamide, bromoform, photopolymerisation, chain transfer
Volume	Vol.41 No.5/2 (OCTOBER 2014)
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