文献类型：期刊文献

英文题名：Rheology control by modulating hydrophobic and inclusive associations of side-groups in poly (acrylic acid)

作者：Wang, Jie[1];Li, Li[1];Ke, Hailan[1];Liu, Peng[1];Zheng, Li[1];Guo, Xuhong[1];Lincoln, Stephen F.[2]

机构：[1]E China Univ Sci & Technol, State Key Lab Chem Engn, Shanghai 200237, Peoples R China;[2]Univ Adelaide, Sch Chem & Phys, Adelaide, SA 5005, Australia

年份：2009

卷号：4

期号：5

起止页码：537

外文期刊名：ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000271441300006)】；

基金：We gratefully acknowledge NSFC Grant 20774030, Shanghai Shuguang Plan Project 06SG35, Shanghai Pujiang Talent Project 08PJ14036 and 07PJ14022 for support of this work.

语种：英文

外文关键词：cyclodextrin; hydrophobic interaction; inclusion association; rheology

摘要：In this article we demonstrated that the viscosities of modified poly (acrylic acid) (PAA) Solutions were tunable by modulating the hydrophobic and inclusion association between alkyl groups and beta-cyclodextrin (beta-CD) groups grafted to PAA. The viscosity can be controlled by changing the host-guest molar ratio, alkyl chain length, polymer concentration, salt concentration, pH value, temperature, or addition of native beta-CD. A viscosity maximum for inclusive polymer networks constructed by mixing hydrophobically modified PAA (HMPAA) and beta-CD-modified PAA (beta-CDPAA) appeared at the alkyl : beta-CD molar ratio of 1 : 1, which implies the inclusion association between HM and beta-CD grafts is binary. Longer side chain length or higher polymer concentration led to higher viscosity for aqueous HMPAA solution with only hydrophobic association or its mixture with beta-CDPAA with inclusion association. Monotonically increasing the ionic strength or pH value resulted in a viscosity maximum due to the competition between electrostatic repulsion and hydrophobic or inclusive association. The hydrophobic interactions of alkyl groups could be masked by native beta-CD, and the networks of HMPAA and beta-CDPAA mixture deconstructed upon addition of native beta-CD molecules. The storage modulus and loss modulus of hydrophobic HMPAA and inclusive HMPAA + beta-CDPAA solutions obey time-temperature superposition. The horizontal and vertical temperature shift factors obeyed a simple-exponential Arrhenius relationship, where the activation energies for hydrophobic association system were found to be 3.4 and -12.1 kJ/mol, and for inclusive association system 53.9 and -2.9 kJ/mol, respectively. (C) 2009 Curtin University of Technology and John Wiley & Sons, Ltd.