微环境对疏水缔合水凝胶性能的影响研究

发布时间：2018-07-29 05:40

【摘要】：疏水缔合水凝胶是一种物理交联型凝胶,其三维网络的交联点由疏水缔合微区构成。这种疏水基团间的相互作用具有动态可逆性,故疏水缔合水凝胶具有一些传统化学凝胶所不具备的特殊性能,例如高机械强度、自愈合及二次加工的特性。因此,其在近年来逐渐成为了科研工作者们关注的热点,并且在油田开采、污水净化、涂料和生物医学等生产生活的各个方面发挥了重要的作用。当人们都将目光着眼于疏水缔合水凝胶作为材料的应用前景上时,凝胶的基础理论研究却进展缓慢。一些新型水凝胶的性能与行为缺乏系统的理论支持,造成了性能预判与按需构筑的障碍。比如,同一种凝胶在不同环境下的性能和行为,与环境因子对网络结构的影响息息相关。本文正是以此为出发点,将问题集中于微环境对疏水缔合水凝胶机械性能与溶胀行为的影响,探究影响因素与机制,并对凝胶内部网络结构及其性能与行为进行更为深入的研究与探讨。因此,本文选用丙烯酰胺(AM)为亲水主单体,实验室自主合成的辛基酚聚氧乙烯(10)醚丙烯酸酯(OP10-AC)为疏水单体,在表面活性剂十二烷基硫酸钠(SDS)和引发剂过硫酸钾(KPS)的作用下,采用胶束共聚合的方法制备所需疏水缔合水凝胶,并对其微环境实施改变,从而进行系统的探究。首先,选取了五组含不同SDS组分的凝胶配比,并将无机盐NaCl作为改变凝胶微环境的因素加入到合成体系内,制备出了含有NaCl的疏水缔合水凝胶,分别对其机械性能以及溶胀行为进行了研究。通过单向拉伸实验,得到了凝胶的断裂强度和模量等宏观机械性能的参数。实验结果显示,尽管五组凝胶中SDS的含量不同,但其断裂强度随NaCl和SDS摩尔比的增加,呈现相同的趋势,均为“上升-下降-上升-下降”的“M”型走势。此外,利用Mooney-Rivlin理论计算了凝胶的微观网络参数,对凝胶的内部网络结构进行了剖析,结果表明,NaCl的加入造成凝胶网络中有效交联密度下降,且NaCl加入量越多交联密度下降幅度越大。在对凝胶溶胀行为的测定实验中,可以发现,凝胶的溶胀程度、水中寿命与网络结构密切相关。结合第二章的实验结果,可知:有效交联密度与溶胀速度和溶胀比呈现反比关系。除此之外,当溶胀介质中含有NaCl时,凝胶的溶胀行为主要受两方面的影响:一是盐析作用,其能够加强疏水缔合的强度;二是渗透压的作用,阻碍凝胶对水分的吸收。在两种作用的综合影响下,凝胶在NaCl溶液中溶胀时会具有较低的溶胀比和较长的寿命。其次,除了无机盐NaCl的影响之外,还探究了环境因子表面活性剂SDS对凝胶溶胀行为的影响。利用含有SDS的溶液对凝胶进行溶胀测试,是对其微环境中SDS情况进行改变的方式,并同时能够得到相应的溶胀行为。结果表明,一方面,SDS作为凝胶合成过程中表面活性剂,其对凝胶疏水缔合交联点的解缔合具有促进作用,加速凝胶的溶胀。另一方面作为一种磺酸盐,渗透压会对凝胶的溶胀产生影响,溶胀度会随着SDS浓度的升高而减小。综上所述,本篇论文通过改变凝胶中小分子无机盐NaCl和大分子表面活性剂SDS两种微环境因子,对疏水缔合水凝胶的机械性能以及溶胀行为进行了相关研究,并对其影响机制、交联情况以及内部构筑展开了详细探讨。凝胶在宏观条件中的种种性能和行为皆归因于其微环境下网络结构的变化。对辛基酚聚氧乙烯醚疏水缔合凝胶在微环境下的机械性能和溶胀行为建立了理论基础,为准确预判与按需构筑提供了方法,为拓展应用和开辟前景奠定了基石。
[Abstract]:Hydrophobically linked hydrogel is a physical crosslinked gel. The crosslinking point of its three-dimensional network is composed of hydrophobically associating microregions. The interaction between these hydrophobic groups is dynamic and reversible, so hydrophobic hydrogels have special properties that some traditional chemical gels do not possess, such as high mechanical strength, self healing and two processing. Therefore, in recent years, it has become a hot spot of concern for researchers, and plays an important role in all aspects of production and life of oil field mining, sewage purification, coating and biomedicine. When people focus on the application prospect of hydrophobic gel as material, basic theoretical study of gel is studied. However, the performance and behavior of some new hydrogels lack systematic theoretical support, resulting in the barrier of performance prediction and demand. For example, the performance and behavior of the same gel in different environments is closely related to the impact of environmental factors on the network structure. This is the starting point for this paper to focus the problem on the micro environment. The effects of the mechanical properties and swelling behavior of hydrophobically combined hydrogel were investigated, and the influence factors and mechanisms were explored, and the internal network structure and performance and behavior of the gel were further studied and discussed. Therefore, the AM was used as the hydrophilic main monomer and the main synthesis of octyl phenol polyoxyethylene (10) ether acrylate (OP1) in the laboratory. 0-AC) for the hydrophobic monomer, under the action of the surface active agent twelve alkyl sulfate (SDS) and the initiator potassium persulfate (KPS), the hydrophobic combined hydrogel was prepared by the micellar copolymerization, and the microenvironment was changed to make a systematic inquiry. First, five groups of gel ratios containing different SDS components were selected and the inorganic compounds were selected. As a factor to change the microenvironment of the gel, salt NaCl was added into the synthetic system, and the hydrophobic hydrogel containing NaCl was prepared. The mechanical properties and swelling behavior of the gel were studied. The parameters of the macroscopic mechanical properties, such as the fracture strength and modulus of the gel, were obtained by the unidirectional tensile test. The experimental results showed that five groups were in spite of the experimental results. The content of SDS in the gel is different, but the breaking strength of the gel increases with the increase of NaCl and SDS molar ratio, which is the "M" trend of "rise drop - rise - drop". Furthermore, the micro network parameters of the gel are calculated by Mooney-Rivlin theory, and the internal network structure of the gel is analyzed. The results show that NaCl is added. The effective crosslinking density decreased in the gel network, and the more the NaCl added, the greater the cross-linking density decreased. In the test of the swelling behavior of the gel, it is found that the swelling degree of the gel and the life of the water are closely related to the network structure. The effective crosslinking density and swelling speed and dissolution can be found in the second chapters. The swelling ratio is inversely proportional. In addition, when the swelling medium contains NaCl, the swelling behavior of the gel is mainly affected by two aspects: one is the salting out effect, which can strengthen the strength of the hydrophobicity Association; the two is the osmotic pressure, which hinders the absorption of the water. Under the comprehensive effect of two kinds of use, the gel will be swelling in the NaCl solution. It has a lower swelling ratio and longer life. Secondly, in addition to the effect of the inorganic salt NaCl, the effect of the environmental factor surfactant SDS on the swelling behavior of the gel is also explored. The swelling test of the gel with a solution containing SDS is the way to change the SDS condition in the microenvironment, and the corresponding swelling can be obtained at the same time. The results show that, on the one hand, as a surface active agent in the gel synthesis process, SDS promotes the deactivation of the gel hydrophobic association crosslinking point and accelerates the swelling of the gel. On the other hand, as a sulfonate, osmotic pressure will affect the swelling of the gel, and the dilatancy will decrease with the increase of the concentration of SDS. In this paper, the mechanical properties and swelling behavior of hydrophobic connective hydrogel were studied by changing the two microenvironmental factors of NaCl and SDS, and the mechanism, crosslinking and internal construction of the gel were discussed in detail. The properties of the gel in the macro conditions were discussed. The mechanical properties and swelling behavior of octyl polyoxyethylene ether hydrophobically associating gel in microenvironment were established, which provided a method for accurate prediction and construction, and laid the foundation for expanding the application and opening the foreground.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O648.17

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