Rheological Study of Physical Cross-Linked Quaternized Cellulose Hydrogels Induced by 尾-Glycerophosphate
详细信息 查看全文
- 作者：Jun You ; Jinping Zhou ; Qian Li ; Lina Zhang
- 刊名：Langmuir
- 出版年：2012
- 出版时间：March 20, 2012
- 年：2012
- 卷：28
- 期：11
- 页码：4965-4973
- 全文大小：507K
- 年卷期：v.28,no.11(March 20, 2012)
- ISSN：1520-5827
文摘
As a weak base, 尾-glycerophosphate (尾-GP) was used to spontaneously initiate gelation of quaternized cellulose (QC) solutions at body temperature. The QC/尾-GP solutions are flowable below or at room temperature but gel rapidly under physiological conditions. In order to clarify the sol鈥揼el transition process of the QC/尾-GP systems, the complex was investigated by dynamic viscoelastic measurements. The shear storage modulus (G鈥?/i>) and loss modulus (G鈥? as a function of (1) concentration of 尾-GP (c尾-GP), (2) concentration of QC (cQC), (3) degree of substitution (DS; i.e., the average number of substituted hydroxyl groups in the anhydroglucose unit) of QC, (4) viscosity-average molecular weight (M畏) of QC, and (5) solvent medium were studied by the oscillatory rheology. The sol鈥揼el transition temperature of QC/尾-GP solutions decreased with an increase of cQC and c尾-GP, the M畏 of QC, and a decrease of the DS of QC and pH of the solvent. The sol鈥揼el transition temperature and time could be easily controlled by adjusting the concentrations of QC and 尾-GP, M畏 and DS of QC, and the solvent medium. Gels formed after heating were irreversible; i.e., after cooling to lower temperature they could not be dissolved to become liquid again. The aggregation and entanglement of QC chains, electrostatic interaction, and hydrogen bonding between QC and 尾-GP were the main factors responsible for the irreversible sol鈥揼el transition behavior of QC/尾-GP systems.