Ultrasound degradation of xanthan polymer in aqueous solution: Its scission mechanism and the effect of NaCl incorporation

Saleh, H.M. and Annuar, M.S.M. and Simarani, K. (2017) Ultrasound degradation of xanthan polymer in aqueous solution: Its scission mechanism and the effect of NaCl incorporation. Ultrasonics Sonochemistry, 39. pp. 250-261. ISSN 1350-4177, DOI https://doi.org/10.1016/j.ultsonch.2017.04.038.

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Official URL: https://doi.org/10.1016/j.ultsonch.2017.04.038

Abstract

Degradation of xanthan polymer in aqueous solution by ultrasonic irradiation was investigated. The effects of selected variables i.e. sonication intensity, irradiation time, concentration of xanthan gum and molar concentration of NaCl in solution were studied. Combined approach of full factorial design and conventional one-factor-at-a-time was applied to obtain optimum degradation at sonication power intensity of 11.5 W cm−2, irradiation time 120 min and 0.1 g L−1 xanthan in a salt-free solution. Molecular weight reduction of xanthan gum under sonication was described by an exponential decay function with higher rate constant for polymer degradation in the salt free solution. The limiting molecular weight where fragments no longer undergo scission was determined from the function. The incorporation of NaCl in xanthan solution resulted in a lower limiting molecular weight. The ultrasound-mediated degradation of aqueous xanthan polymer chain agreed with a random scission model. Side chain of xanthan polymer is proposed to be the primary site of scission action.

Item Type: Article
Funders: University of Malaya. Research grants PG057/2013A, FP020-2013A, RG330-15AFR and RP031C-15AET
Uncontrolled Keywords: Xanthan gum; Ultrasound; Chain scission; Molecular weight; Ionic strength
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculty of Science > Institute of Biological Sciences
Depositing User: Ms. Juhaida Abd Rahim
Date Deposited: 20 Jul 2017 07:11
Last Modified: 20 Jul 2017 07:11
URI: http://eprints.um.edu.my/id/eprint/17543

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