化学与物理交联协同增韧聚丙烯酰胺水凝胶的制备和性质表征

发布时间：2018-03-11 18:51

本文选题：化学交联　切入点：物理交联　出处：《长春工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：水凝胶作为一种亲水的凝胶具有相当高的含水量,其含水量与生物组织相似(70%)甚至可达到更高。水凝胶具有良好的生物相容性,且表现出良好的柔韧性,刺激响应能力,以上性能为水凝胶在生物领域,组织工程方向的应用奠定了基础。然而,由于水凝胶含水量较高,其机械性能相对较差,严重的限制了水凝胶的应用。传统的化学交联水凝胶通过永久,不可逆的共价键相互连接的聚合物链组成,这通常使水凝胶较脆,透明性差,网络结构断裂后不能自愈。但是,化学交联网络结构易于调整,可以改变最终材料的机械性能。因此,传统的化学交联网络结构不可以被忽略,要巧妙加以改善就可以得到强韧水凝胶。在本文中,我们将物理交联与化学交联两种交联方式都引入到水凝胶网络体系中,制备强韧的,具有抗疲劳性能和快速自回复性能的水凝胶。在第一部分实验中,我们将疏水缔合这种交联方式引入到水凝胶网络中作为物理交联中心,同时以N,N′-亚甲基双丙烯酰胺作为化学交联剂,通过自由基聚合方式与亲水主链聚丙烯酰胺相链接,作为化学交联中心。在杂化水凝胶网络体系中,化学交联为水凝胶网络提供了一个刚性骨架,来支撑着整个水凝胶网络基质,疏水缔合作为物理交联中心能够通过胶束变形和甲基丙烯酸月桂酯(LMA)链的可逆解缠来有效的耗散能量,使得这种杂化水凝胶在压缩应变为95%时,压缩强度可以达到8 MPa。此外,在连续压缩循环测试中,杂化水凝胶展现出了时间依赖性,快速自恢复性,抗疲劳性质。在第二部分实验中,我们期望得到强韧,具有拉伸性能的水凝胶,因此,我们改进了物理交联中心,并调节了化学交联点的密度,从而得到了具有高拉伸强度,高断裂伸长率的具有快速自恢复性和抗疲劳性质的由甲基丙烯酸月桂酯-聚丙烯酸丁酯微球(LMA-PBA)混合胶束诱导的强韧杂化水凝胶(LMA-PBA+MBA gel)。在这个杂化水凝胶网络体系中,化学交联仍然作为一个刚性骨架支撑着整个水凝胶网络基质,LMA-PBA混合胶束作为物理交联点,可通过胶束形变,LMA链的可逆解缠,PBA软粒子变形以及LMA-PBA间的可逆交联来耗散大量的能量,从而将有效的能量耗散机制引入到水凝胶网络体系中,使得这种杂化水凝胶具有相当好的拉伸性能,最大拉伸应力可达到1.4 MPa,断裂伸长率可达到2500%,同时具有快速自恢复性,抗疲劳性。这两种通过物理交联与化学交联协同作用的,具有快速自恢复性,抗疲劳性的杂化水凝胶均可以拓展在负载材料方向的生物领域的应用,例如,水凝胶软骨、筋腱,人造肌肉和组织工程等。
[Abstract]:As a hydrophilic gel, hydrogel has very high water content, and its water content is even higher than that of biological tissue. Hydrogel has good biocompatibility, good flexibility and irritability. These properties lay a foundation for the application of hydrogels in biological and tissue engineering fields. However, the mechanical properties of hydrogels are relatively poor due to their high water content. The application of hydrogels is severely restricted. Traditional chemically crosslinked hydrogels are made up of permanent, irreversible, covalently linked polymer chains, which usually make hydrogels brittle, less transparent, and unable to heal themselves after the network breaks. The chemical crosslinking network structure is easy to adjust and can change the mechanical properties of the final material. Therefore, the traditional chemical crosslinking network structure can not be ignored. Both physical and chemical crosslinking methods are introduced into the hydrogel network system to prepare strong and tough hydrogels with fatigue resistance and fast self-recovery. In the first part of the experiment, The hydrophobically associating crosslinking method is introduced into hydrogel networks as the physical crosslinking center, and the hydrophilic polyacrylamide is linked to the hydrophilic main chain polyacrylamide by means of free radical polymerization, using NNT-methylene bisacrylamide as the chemical crosslinking agent. In hybrid hydrogel networks, chemical crosslinking provides a rigid skeleton for hydrogel networks to support the entire hydrogel network matrix. Hydrophobic association, as a physical crosslinking center, can effectively dissipate energy through micelle deformation and reversible unwinding of the LMA-methacrylate chain, resulting in the compression strength of the hybrid hydrogel reaching 8 MPA when the compression strain is 95%. In continuous compression cycle testing, hybrid hydrogels exhibit time-dependent, fast self-recovery, anti-fatigue properties. In the second part of the experiment, we expect to obtain strong and tough hydrogels with tensile properties, so, We improved the physical crosslinking centers and adjusted the density of the chemical crosslinking points, which resulted in high tensile strength. A strong and toughened hybrid hydrogel, LMA-PBA MBA gelatin, with high elongation at break, which has the properties of rapid self-recovery and fatigue resistance, is induced by the mixed micelle of lauryl methacrylate and polybutyl acrylate microspheres (LMA-PBA). In this hybrid hydrogel network system, Chemical crosslinking is still used as a rigid skeleton to support the whole hydrogel network matrix LMA-PBA mixed micelles as physical crosslinking points, which can dissipate a large amount of energy through the reversible unwinding of the LMA-PBA chains and the deformation of soft particles in the LMA-PBA. Thus, the effective energy dissipation mechanism is introduced into the hydrogel network system, which makes the hybrid hydrogel have quite good tensile properties, the maximum tensile stress can reach 1.4 MPA, the elongation at break can reach 2500, and the hybrid hydrogel has a rapid self-recovery. Fatigue resistance. Both of these hybrid hydrogels, which combine physical and chemical crosslinking with quick self-healing, fatigue resistance, can be extended to biological applications in the direction of loaded materials, such as hydrogel cartilage, tendons, Artificial muscle and tissue engineering, etc.
【学位授予单位】：长春工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O648.17

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