Distributed midpoint chain scission in ultrasonic degradation of polymers

Sivalingam, G and Agarwal, Nitin and Madras, Giridhar (2004) Distributed midpoint chain scission in ultrasonic degradation of polymers. In: AIChE Journal, 50 . pp. 2258-2265.

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Abstract

The ultrasonic degradation of poly(bisphenol A carbonate), poly(\varepsilon-caprolactone), and poly(vinyl acetate) was investigated with various solvents such as benzene, monochlorobenzene, and dichlorobenzene. The time evolution of molecular weight was determined using gel permeation chromatography. A limiting molecular weight was observed for all the systems and was a function of solvent properties. The degradation rates increased with increase in viscosity and decrease in vapor pressure. The polydispersity reached a maximum before reaching a constant value at longer times. The experimental data indicate that the breakage of the polymer is around midpoint, with a distribution rather than an ideal midpoint scission. A continuous distribution model with a stoichiometric kernel based on Lorentzian probability distribution function was developed to satisfactorily model the experimental data.

Item Type:	Journal Article
Publication:	AIChE Journal
Publisher:	American Institute of Chemical Engineers
Additional Information:	The copyright belongs to American Institute of Chemical Engineers.
Keywords:	ultrasonic degradation;limiting molecular weight;midpoint chain scission;poly bisphenol a carbonate;poly caprolactone;poly vinyl acetate
Department/Centre:	Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	08 Nov 2005
Last Modified:	19 Sep 2010 04:21
URI:	http://eprints.iisc.ac.in/id/eprint/3949

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