Rheological Images of Dynamic Covalent Polymer Networks and Mechanisms behind Mechanical and Self-Healing Properties

doi:10.1021/ma202461e

CORC > 化学研究所 > 中国科学院化学研究所

	Rheological Images of Dynamic Covalent Polymer Networks and Mechanisms behind Mechanical and Self-Healing Properties
	Liu, Fuyong 2; Li, Fuya 1; Deng, Guohua 1; Chen, Yongming 3; Zhang, Baoqing 2; Zhang, Jun 2; Liu, Chen-Yang 2
刊名	MACROMOLECULES
	2012-02-14
卷号	45 期号:3 页码:1636-1645
ISSN号	0024-9297
DOI	10.1021/ma202461e
英文摘要	In our previous work [Macromolecules 2010, 43, 1191-1194], we synthesized dynamic covalent cross-linked polymer gels through condensation of acylhydrazines at the chain ends of poly(ethylene oxide) (A(2)) and aldehyde groups in tris[(4-formylphenoxy)methy]ethane (B-3) and reported reversible sol-gel transition and self-healing properties of the gels. For those dynamic gels, this paper examines the gelation kinetics and rheological behavior in pre- and postgelation stages and discusses the molecular mechanism underlying the mechanical and self-healing properties. The results showed that the condensation reaction before the critical gelation point can be treated as the pseudo-second-order reaction. The scaling exponent n (=0.75) for the frequency dependence of the complex moduli at the critical gel point, the exponent gamma (=1.5) for the concentration dependence of the viscosity in the pregel regime, and the exponent z (=2.5) for the concentration dependence of the equilibrium modulus in the postgel regime were found to not exactly obey the relationship for covalent gels, n = z/(z + gamma), possibly because of the dynamic nature of the gels. The terminal relaxation of the dynamic gels at high temperature (125 degrees C) accorded with the Maxwellian model, as often observed for transient associating networks. In contrast, at low temperature (25 degrees C) where this transient network reorganization was essentially quenched in a time scale of experiments (similar to 50 s), the uniaxial stress-strain behavior of the gel was well described by the classical model of rubber elasticity sigma(eng) = G(lambda - 1/lambda(2)) up to 300% stretch (as similar to the behavior of usual gels chemically cross-linked in a swollen state). Ultimately, the gel cut into two pieces was found to exhibit self-healing under ambient conditions in 8 and 24 h, respectively, when the edges of those pieces were coated and not coated with acid (catalyst for dynamic covalent bond formation).
语种	英语
出版者	AMER CHEMICAL SOC
WOS记录号	WOS:000300124200057
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/48491]
专题	中国科学院化学研究所
通讯作者	Deng, Guohua
作者单位	1.S China Univ Technol, Sch Chem & Chem Engn, Guangzhou 510640, Guangdong, Peoples R China 2.Chinese Acad Sci, Beijing Natl Lab Mol Sci, CAS Key Lab Engn Plast, Joint Lab Polymer Sci & Mat,Inst Chem, Beijing 100190, Peoples R China 3.Chinese Acad Sci, Beijing Natl Lab Mol Sci, State Key Lab Polymer Phys & Chem, Joint Lab Polymer Sci & Mat,Inst Chem, Beijing 100190, Peoples R China
推荐引用方式 GB/T 7714	Liu, Fuyong,Li, Fuya,Deng, Guohua,et al. Rheological Images of Dynamic Covalent Polymer Networks and Mechanisms behind Mechanical and Self-Healing Properties[J]. MACROMOLECULES,2012,45(3):1636-1645.
APA	Liu, Fuyong.,Li, Fuya.,Deng, Guohua.,Chen, Yongming.,Zhang, Baoqing.,...&Liu, Chen-Yang.(2012).Rheological Images of Dynamic Covalent Polymer Networks and Mechanisms behind Mechanical and Self-Healing Properties.MACROMOLECULES,45(3),1636-1645.
MLA	Liu, Fuyong,et al."Rheological Images of Dynamic Covalent Polymer Networks and Mechanisms behind Mechanical and Self-Healing Properties".MACROMOLECULES 45.3(2012):1636-1645.