壳聚糖接枝聚丙烯酰胺在水溶液中加热时的动力学和流变行为

Dynamics and Rheological Behavior of Chitosan-Grafted-Polyacrylamide in Aqueous Solution upon Heating.

作者信息

Wang Mengjie, Shangguan Yonggang, Zheng Qiang

机构信息

MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China.

出版信息

Polymers (Basel). 2020 Apr 15;12(4):916. doi: 10.3390/polym12040916.

DOI:10.3390/polym12040916

PMID:32326596

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC7240601/

Abstract

In this work, the transformation of chitosan-grafted-polyacrylamide (GPAM) aggregates in aqueous solution upon heating was explored by cryo-electron microscope (cryo-TEM) and dynamic light scattering (DLS), and larger aggregates were formed in GPAM aqueous solution upon heating, which were responsible for the thermo-thickening behavior of GPAM aqueous solution during the heating process. The heating initiates a transformation from H-bonding aggregates to a large-sized cluster formed by self-assembled hydrophobic chitosan backbones. The acetic acid (HAc) concentration has a significant effect on the thermo-thickening behavior of GPAM aqueous solution; there is a critical value of the concentration (>0.005 M) for the thermo-thickening of 10 mg/mL GPAM solution. The concentration of HAc will affect the protonation degree of GPAM, and affect the strength of the electrostatic repulsion between GPAM molecular segments, which will have a significant effect on the state of the aggregates in solution. Other factors that have an influence on the thermo-thickening behavior of GPAM aqueous solution upon heating were investigated and discussed in detail, including the heating rate and shear rate.

摘要

在本工作中，通过冷冻电子显微镜（cryo-TEM）和动态光散射（DLS）研究了壳聚糖接枝聚丙烯酰胺（GPAM）聚集体在水溶液中加热时的转变，加热时GPAM水溶液中形成了更大的聚集体，这是加热过程中GPAM水溶液热增稠行为的原因。加热引发了从氢键聚集体到由自组装疏水壳聚糖主链形成的大尺寸簇的转变。乙酸（HAc）浓度对GPAM水溶液的热增稠行为有显著影响；对于10 mg/mL GPAM溶液的热增稠，浓度存在一个临界值（>0.005 M）。HAc的浓度会影响GPAM的质子化程度，并影响GPAM分子链段之间静电排斥的强度，这将对溶液中聚集体的状态产生显著影响。还详细研究和讨论了其他影响加热时GPAM水溶液热增稠行为的因素，包括加热速率和剪切速率。