多种刺激响应及多重形状记忆水凝胶的构筑及性能研究

发布时间：2018-06-03 06:52

本文选题：形状记忆水凝胶 + 多种刺激响应　；参考：《中北大学》2017年硕士论文

【摘要】：形状记忆水凝胶作为一种能够在外界刺激下,如:pH、温度、光等,使临时形状恢复到初始形状的智能高分子材料,近些年来受到越来越多的关注。然而,目前的形状记忆水凝胶仍然存在着刺激响应性单一和固定的临时形状数量有限等不足,从而限制了其应用范围。针对这两方面较为明显的不足,我们分别制备了具有多种刺激响应性的形状记忆水凝胶和多重形状记忆水凝胶。本文的主要研究内容如下:(1)具有多种刺激响应性形状记忆水凝胶。将壳聚糖(CS)、葡聚糖二醛(Odex)和丙烯酰胺(AAm)混合,通过AAm聚合形成第一网络(PAAm)作为永久网络保持原始形状,通过动态席夫碱键或金属配位作用形成动态第二网络临时交联点,赋予水凝胶形状记忆功能。首先,利用CS的胺基和Odex的醛基,在碱性条件下形成动态席夫碱键,记忆临时形状,并且可以分别在酸性、丙氨酸或维生素B6溶液中使临时形状恢复到初始形状。其次,水凝胶中的CS可以和多种过渡金属离子发生配位作用。以Ag+为例,临时形状可以分别在EDTA·2Na、卤素、草酸或硫酸溶液等外界条件下恢复到初始形状。结合两种动态共价键还可以赋予水凝胶三重形状记忆功能,其临时形状不仅可以实现程序化的恢复,还可以实现一步恢复到初始形状。(2)具有多重形状记忆功能的水凝胶。构筑内部含有CS的PAAm水凝胶。PAAm网络作为永久网络保持原始形状。由于CS不仅可以在碱性条件下形成物理微晶结构,还可以在饱和食盐水中形成链缠结结构,固定临时形状,实现双重形状记忆功能。因此,利用这两种物理作用可以分别赋予水凝胶双重形状记忆功能。此外,由于在固定临时形状时是一个外界刺激逐渐向水凝胶内部渗透的过程,所以水凝胶还可以在一种刺激下逐步固定多个临时形状赋予水凝胶多重形状记忆功能。结合两种物理作用,水凝胶还可以实现三重形状记忆功能。
[Abstract]:Shape memory hydrogel, as an intelligent polymer material, which can be stimulated by outside, such as: ph, temperature, light and so on, has attracted more and more attention in recent years. However, the current shape memory hydrogel still has the shortcomings of single stimulus response and limited number of fixed temporary shapes, which limits its application. In view of the obvious shortcomings of these two aspects, we have prepared shape memory hydrogels and multiple shape memory hydrogels with various stimuli response respectively. The main contents of this paper are as follows: 1) there are many stimulus-responsive shape memory hydrogels. Chitosan, dextran dialdehydes (Odexa) and acrylamide (Aam) were mixed, the first network was formed by AAm polymerization, and the first network was formed as a permanent network to maintain the original shape, and the dynamic Schiff base bond or metal coordination was used to form the dynamic second network temporary crosslinking point. Give hydrogel shape memory function. First, using the amino group of CS and the aldehyde group of Odex, the dynamic Schiff base bond is formed under alkaline condition, and the temporary shape can be recovered to the initial shape in acidic, alanine or vitamin B6 solutions, respectively. Secondly, CS in hydrogel can coordinate with a variety of transition metal ions. Taking Ag as an example, the temporary shape can be restored to its initial shape under the external conditions of EDTA _ 2Na, halogen, oxalic acid or sulfuric acid respectively. Combined with two kinds of dynamic covalent bonds, hydrogels can also be endowed with triple shape memory function. The temporary shape of hydrogels can be restored not only by program, but also by one-step restoration to initial shape. A PAAm hydrogel. PAAm network containing CS is constructed as a permanent network to preserve its original shape. Because CS can not only form physical microcrystalline structure in alkaline condition, but also form chain entanglement structure in saturated salt water, fix temporary shape, and realize double shape memory function. Therefore, hydrogels can be given dual shape memory function by using these two physical functions. In addition, hydrogel can immobilize multiple shape memory function under one stimulus, because it is a process that external stimulation permeates the hydrogel gradually when the temporary shape is fixed. Combined with two physical functions, hydrogel can also achieve triple shape memory function.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O648.17;TB381

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