Molecular weight kinetics and chain scission models for dextran polymers during ultrasonic degradation

Yuanyuan Pu; Qingsong Zou; Dianzhi Hou; Yiping Zhang; Shan Chen

doi:10.1016/j.carbpol.2016.09.017

Molecular weight kinetics and chain scission models for dextran polymers during ultrasonic degradation

Carbohydr Polym. 2017 Jan 20:156:71-76. doi: 10.1016/j.carbpol.2016.09.017. Epub 2016 Sep 7.

Authors

Yuanyuan Pu¹, Qingsong Zou², Dianzhi Hou³, Yiping Zhang⁴, Shan Chen⁵

Affiliations

¹ Center for Sugar Engineering and Technology Research, Guangxi University, Nanning 530004, PR China; College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, PR China. Electronic address: yuanyuan.pu@ucdconnect.ie.
² Center for Sugar Engineering and Technology Research, Guangxi University, Nanning 530004, PR China; College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, PR China. Electronic address: Qingsong.Zou@ul.ie.
³ Center for Sugar Engineering and Technology Research, Guangxi University, Nanning 530004, PR China; College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, PR China. Electronic address: xiaozhihou90@126.com.
⁴ Center for Sugar Engineering and Technology Research, Guangxi University, Nanning 530004, PR China; College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, PR China. Electronic address: feyzhang1989@mail.scut.edu.cn.
⁵ Center for Sugar Engineering and Technology Research, Guangxi University, Nanning 530004, PR China. Electronic address: chenshan@gxu.edu.cn.

PMID: 27842854
DOI: 10.1016/j.carbpol.2016.09.017

Abstract

Ultrasonic degradation of six dextran samples with different initial molecular weights (IMW) has been performed to investigate the degradation behavior and chain scission mechanism of dextrans. The weight-average molecular weight (Mw) and polydispersity index (D value) were monitored by High Performance Gel Permeation Chromatography (HPGPC). Results showed that Mw and D value decreased with increasing ultrasonic time, resulting in a more homologous dextran solution with lower molecular weight. A significant degradation occurred in dextrans with higher IMW, particularly at the initial stage of the ultrasonic treatment. The Malhotra model was found to well describe the molecular weight kinetics for all dextran samples. Experimental data was fitted into two chain scission models to study dextran chain scission mechanism and the model performance was compared. Results indicated that the midpoint scission model agreed well with experimental results, with a linear regression factor of R²>0.99.

Keywords: Chain scission; Dextran; Kinetics; Molecular weight; Ultrasound.