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Ultrasonic Degradation of Poly(acrylic acid)

Shukla, Neelesh Bharti and Darabonia, Nagu and Madras, Giridhar (2009) Ultrasonic Degradation of Poly(acrylic acid). In: Journal Of Applied Polymer Science, 112 (2). pp. 991-997.

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Abstract

The ultrasonic degradation of poly(acrylic acid), a water-soluble polymer, was studied in the presence of persulfates at different temperatures in binary solvent Mixtures of methanol and water. The degraded samples were analyzed by gel permeation chromatography for the time evolution of the molecular weight distributions. A continuous distribution kinetics model based on midpoint chain scission was developed, and the degradation rate coefficients were determined. The decline in the rate of degradation of poly(acrylic acid) with increasing temperature and with an increment in the methanol content in the binary solvent mixture of methanol and water was attributed to the increased vapor pressure of the solutions. The experimental data showed an augmentation of the degradation rate of the polymer with increasing oxidizing agent (persulfate) concentrations. Different concentrations of three persulfates-potassium persulfate, ammonium persulfate, and sodium persulfate-were used. It was found that the ratio of the polymer degradation rate coefficient to the dissociation rate constant of the persulfate was constant. This implies that the ultrasonic degradation rate of poly(acrylic acid) can be determined a priori in the presence of any initiator.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Wiley Periodicals.
Keywords: degradation;gel permeation chromatography (GPC);kinetics (polym.);mass distribution;water-soluble polymers.
Department/Centre: Division of Mechanical Sciences > Chemical Engineering
Date Deposited: 24 Mar 2009 09:53
Last Modified: 19 Sep 2010 05:29
URI: http://eprints.iisc.ernet.in/id/eprint/19564

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