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Photocatalytic degradation of poly(acrylamide-co-acrylic acid)
Published in American Chemical Society
2008
Volume: 112
   
Issue: 30
Pages: 8928 - 8935
Abstract
Poly(acrylamide-co-acrylic acid) copolymers of different compositions were synthesized and characterized. The copolymers were statistical with a relatively high percentage of acrylamide units, as determined by 13C NMR. Reactivity ratios calculated by the Finemann-Ross and Kelen-Tudos methods showed that the copolymers were random with a reactivity ratio of rAM = 3.76 and rAA = 0.28. The photolytic and photocatalytic degradation of the copolymers and the homopolymers was conducted in the presence of combustion-synthesized nano anatase titania. The degradation of the copolymer in the presence of combustion-synthesized titania was significantly higher than that observed in the presence of commercial titania, Degussa P-25. The degradation was modeled by using continuous distribution kinetics by following the time evolution of molecular weight distribution. The degradation follows a two step mechanism, wherein the rapid first step comprises the scission of weak acrylic acid units along the chain which is followed by the breakage of relatively strong acrylamide units. The rate constants for the weak and strong links follow a linear trend with the percentage of acrylic acid and acrylamide in the copolymer, respectively. This linear variation can be correlated with a similar trend observed for the activation energies obtained for the pyrolytic degradation of the polymers. © 2008 American Chemical Society.
About the journal
JournalData powered by TypesetJournal of Physical Chemistry B
PublisherData powered by TypesetAmerican Chemical Society
ISSN15206106