Degradation of Water Soluble Polymers under Combined Ultrasonic and Ultraviolet Radiation

Aarthi, T and Shaama, MS and Madras, Giridhar (2007) Degradation of Water Soluble Polymers under Combined Ultrasonic and Ultraviolet Radiation. In: Industrial & Engineering Chemistry Research, 46 (19). pp. 6204-6210.

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Abstract

The degradation of water soluble polymers, namely, poly(ethylene oxide) (PEO), poly(acrylic acid) (PAA), and poly(vinyl pyrrolidone) (PVP), by ultraviolet (UV) and ultrasound (US) exposure in the presence of combustion solution synthesized $TiO_2$ (CSN $TiO_2$) was investigated. The time evolution of the molecular weight distributions (MWDs) was determined by gel permeation chromatography (GPC). A continuous distribution model based on binary scission was proposed, and the degradation rate coefficient was determined. The degradation of polymers was also investigated with combined simultaneous exposure to UV and US in the presence of CSN $TiO_2$. The model with binary breakage and additive contribution from UV and US fits the experimental values of the number-average molecular weight but not the weight-average molecular weight and thus is not a true representation of the physical process. Therefore, a ternary fragmentation model was developed and used to fit the experimental data successfully. The increase in overall rate of degradation on the combined simultaneous exposure of ultraviolet and ultrasound is due to an increase in the number of scission products per breakage and not due to the increase in the intrinsic rate.

Item Type:	Journal Article
Publication:	Industrial & Engineering Chemistry Research
Publisher:	American Chemical Society
Additional Information:	Copyright of this article belongs to American Chemical Society.
Department/Centre:	Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	17 Dec 2008 11:05
Last Modified:	22 Feb 2012 06:20
URI:	http://eprints.iisc.ac.in/id/eprint/16745

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