基于不同相互作用的形状记忆水凝胶的设计和性能表征

发布时间：2018-03-14 11:23

本文选题：形状记忆材料　切入点：水凝胶　出处：《中国科学技术大学》2017年博士论文　论文类型：学位论文

【摘要】：目前智能材料的研究是一个热门学科,形状记忆材料便是智能材料中的一种。形状记忆材料能够在某一种或多种刺激环境(如pH、光照、氧化还原、电、磁场、温度)中,外力作用下固定住某一临时形状,当再受到刺激时能够恢复到原来的永久形状。形状记忆材料从最初的Ti-Ni为主体的形状记忆金属到各种塑料和橡胶类的形状记忆聚合物,再到新兴的形状记忆水凝胶的形状记忆材料发展。从形状记忆材料的发展趋势可以看出形状记忆水凝胶综合了形状记忆聚合物和智能水凝胶的各种优点,创造了新的研究领域,挖掘出了在分子元器件、微型机器人、生物医学等高新技术领域中巨大的应用潜力。但目前对于形状记忆智能水凝胶的研究大部分还集中在通过疏水作用形成的热响应性形状记忆水凝胶,因此开发研究新型的热响应型形状记忆水凝胶、其它响应型形状记忆水凝胶以及多种响应型水凝胶,以及拓展形状记忆水凝胶的应用领域,成为未来的发展趋势。另外,目前主要的形状记忆水凝胶都是通过化学交联固定水凝胶骨架,利用物理交联来赋予水凝胶形状记忆的功能。因为有化学交联的存在,水凝胶不能重复利用,对材料来说很浪费。因此,综合以上分析,本论文结合金属离子与一些基团之间的配位交联作用、疏水链段之间的疏水作用以及主客体相互作用,制备了几种新型的形状记忆水凝胶体系并进行机理和性能研究。具体研究内容如下:(1)利用丙烯酰胺(AM)、异丙烯膦酸(IPPA)和大分子交联剂聚乙二醇双丙烯酸酯(PEGDA)合成了一种新型的水凝胶。该水凝胶中的磷酸根可以与三价铁离子(Fe~(3+))配位交联,通过氧化还原反应使三价铁离子还原为二价铁离子(Fe2+),从而破坏磷酸根与三价铁离子之间的交联作用。另外,通过加入络合剂EDTA·2Na,用更强的络合作用与磷酸根抢夺三价铁离子,从而也使磷酸根和三价铁离子之间的交联破坏。通过两种方式都可控制交联和解交联,从而使水凝胶具有两种刺激响应性形状记忆。我们利用流变仪对水凝胶的性能进行研究,对形状记忆的原理和影响因素进行了分析。(2)利用可聚合阳离子表面活性剂甲基丙烯酸二甲氨基乙酯溴代十六烷(C16DMAEMA)、丙烯酰胺(AM)为单体进行胶束聚合,以甲叉双丙烯酰胺(MBA)为化学交联剂,与α-环糊精混合制备疏水改性聚丙烯酰胺水凝胶。其中利用主客体相互作用,将环糊精引入到疏水链段上,形成疏水链穿插多个环糊精的聚轮烷拓扑结构。XRD、固态~(13)C-NMR、DSC等表征手段证明引入到疏水基团上的环糊精之间的氢键相互作用形成结晶区,并通过结晶区的熔融和结晶形成可使水凝胶实现热响应形状记忆功能。(3)利用丙烯酰胺(AM)、丙烯酸(AA)和疏水单体丙烯酸十八烷酯(C18)共聚合成了一种没有化学交联剂,而是通过疏水缔合作用物理交联的聚合物水凝胶,并通过加入三价铁离子利用与水凝胶中羧基之间的配位络合作用形成第二种物理交联。该水凝胶体系中由于同时存在疏水相互作用和能与三价铁离子配位络合的相互作用,属于由两种物理交联构成的水凝胶。利用疏水作用固定水凝胶的形状,凝胶中的丙烯酸基团与三价铁离子交联,通过还原和络合作用解交联,从而实现水凝胶的形状记忆功能,赋予水凝胶多重响应形状记忆特性。同时,由于水凝胶中不存在化学交联键,大大丰富了水凝胶的种类和应用。
[Abstract]:The research of intelligent materials is a hot subject, shape memory material is a kind of smart material. The shape memory materials can stimulate the environment in one or more (such as pH, light, redox, electric, magnetic field, temperature), under the action of external force to fix a temporary shape. When can be restored to the original permanent shape again when stimulated. The shape memory materials from the original Ti-Ni as the main body of the shape memory metal to shape memory polymer plastic and rubber, and then to the development of shape memory materials shape memory gel. Emerging from the development trend of shape memory materials can be seen shape memory gel synthesis all the advantages of shape memory polymer and intelligent hydrogels, create a new field of study, excavated in the molecular components, micro robot, the use of biomedical and other high-tech fields in large Force. But the shape memory gel response of shape memory of intelligent hydrogels most concentrated in the form of heat through hydrophobic interaction, the study of new type thermal response type shape memory gel so developed, other response type shape memory gel and a variety of responsive hydrogels, and the expansion of the application of shape memory gel, become the trend of development the future. In addition, the shape memory gel is mainly fixed by chemical crosslinking hydrogels, using physical crosslinking to give hydrogel shape memory function. Because of the existence of chemical crosslinking, the hydrogel can not be reused, a waste of materials. Therefore, based on the above analysis, this paper combines between metal ions and some groups Coordination Crosslinking, hydrophobic interaction between the hydrophobic segment and the interaction between subject and object, the preparation of several new Study on the mechanism and performance of shape memory and hydrogel system. The specific contents are as follows: (1) using acrylamide (AM), isopropenyl phosphonic acid (IPPA) and macromolecular crosslinking agent of polyethylene glycol diacrylate (PEGDA) is a new type of hydrogel was synthesized. The hydrogel in phosphate and ferric iron can ion (Fe~ (3+)) Coordination Crosslinking, the ferric ion reduction of two valent iron ions through redox reaction (Fe2+), thus undermining the cross-linking between phosphate and ferric ion. In addition, by adding the complexing agent EDTA 2Na, with a stronger complexation with phosphate from ferric ion thus, the cross-linking between phosphate and ferric ion damage. By two ways can control the settlement so that the crosslinking crosslinking hydrogel with two kinds of stimuli responsive shape memory. We use the research on properties of hydrogel rheometer The principle and influencing factors of shape memory were analyzed. (2) using a polymerizable cationic surfactant two dimethylamino ethyl methacrylate methyl sixteen alkyl bromide (C16DMAEMA), acrylamide (AM) by micellar polymerization monomers with methylene bisacrylamide (MBA) as crosslinking agent, and alpha cyclodextrin mixed preparation of hydrophobically modified polyacrylamide hydrogel. The interaction between subject and object, the cyclodextrin into hydrophobic segments, forming a hydrophobic chain with multiple cyclodextrin polyrotaxanes topology.XRD, solid state ~ (13) C-NMR, DSC characterization means that introduced between the cyclodextrin hydrophobic groups the hydrogen bonding between the formation of crystalline region, and can realize the thermal response of shape memory functional hydrogel formed by melting and crystallization of the crystalline region. (3) using acrylamide (AM), acrylic acid (AA) and hydrophobic acrylic acid alkyl ester eighteen memo (C18) Co The polymerization did not become a chemical cross-linking agent, but by hydrophobic association polymer hydrogel physical crosslinking, and by the addition of ferric ion and using between hydrogel complexation with carboxyl groups to form second kinds of physical crosslinking. The interaction and hydrophobic interaction and ferric ion complexing with the hydrogel in the system, is composed of two physically crosslinked hydrogels. Using shape hydrophobic hydrogel fixed in the gel, acrylic acid groups and ferric ion crosslinking by crosslinking and co reduction, so as to realize the function of shape memory hydrogels, with multiple response shape memory properties of hydrogels. At the same time, due to the chemical crosslinking key does not exist the hydrogel, greatly enriched the types and applications of hydrogels.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O648.17;TB381

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