基于NIPAM的水凝胶与有机凝胶的流变学性能研究
发布时间：2018-09-16 20:58
【摘要】：基于N-异丙基丙烯酰胺(NIPAM)的凝胶具有接近人类体温的低临界溶解温度(LCST)。这种特性使其成为在给药和生物医学工程中有着应用潜力的热敏性聚合物凝胶材料。在许多用于表征凝胶的仪器中,流变仪是探究诸如凝胶、悬浮液、胶体等软物质材料的重要工具。可通过流变学表征凝胶的成胶温度、LCST、多种力学性能以及对施加应变的响应等。在本论文中,我们合成了一系列基于NIPAM的水凝胶或有机凝胶并主要从流变学的角度研究这些凝胶的性能,本文的主要内容如下:第一章介绍了基于NIPAM的凝胶材料、流变学以及流变仪的基本概念。第二章主要涉及在不同甲醇-水混合溶剂中合成的NIPAM与NEAM(N-乙基丙烯酰胺)无规共聚水凝胶。采用温度扫描和单轴压缩测试表征它们的LCST和力学性能。LCST与合成时的溶剂条件无关。在水占主导的混合溶剂中合成的水凝胶的力学性能相对较好。另外可以针对通过温度扫描测得的剪切模量、通过压缩测试测得的压缩模量以及通过原子力显微镜测得的杨氏模量进行比较,因为这三种模量随着合成时溶剂的甲醇摩尔分数变化的趋势相似。在第三章中,采用上述的方法研究了在相同合成的条件下具有不同共聚单体组分的P(NIPAM-co-NEAM)水凝胶随温度变化的流变学性能。结果证明LCST以及模量会随着NIPAM共聚单体含量的增加而减少,这是因为体系亲水-疏水平衡和凝胶形貌多孔性发生了变化。第四章是溶于苯甲醇中的PNIPAM有机凝胶的流变学基础研究。通过温度扫描的结果表明等规度或者浓度过低的PNIPAM样品,在温度扫描过程中无法形成凝胶,因此它们也没有溶胶-凝胶转换温度。而对于其它样品,它们的凝胶强度、溶胶-凝胶转变温度与分子量、等规度和浓度有关。由大应变扫描测试可得知这种有机凝胶的线性黏弹极限会随分子量、等规度、浓度的增加而趋于更小的应变。第五章涉及由NIPAM和多巴胺丙烯酰胺的共聚物(NIDO)与NIPAM与4-乙烯基苯硼酸的共聚物(NIBA)两种聚合物溶液的混合物形成的超分子凝胶(NIBA)的大幅振荡剪切扫描测试,这种材料在两种溶液不同混合比例的条件下,其线性和非线性流变学行为都有所不同。当两种聚合物溶液1:1混合时会形成强度最高的凝胶,而4:1混合物具有明显较低的模量和截然不同的流变学行为。可以从Fourier变换流变学得到高次奇数次谐波强度比一次谐波强度的比例或者从Lissajous曲线的扭曲程度来评价材料的非线性程度。这些超分子凝胶与一般的聚合物熔体和溶液不同,这种超分子凝胶在过大的应变时,非线性程度会有所减小。
[Abstract]:The gel based on N-isopropylacrylamide (NIPAM) has a low critical dissolution temperature (LCST).) close to human body temperature. This property makes it a potential thermosensitive polymer gel material for drug delivery and biomedical engineering. Rheometer is an important tool for exploring soft matter materials such as gel, suspension and colloid in many instruments used to characterize gel. The gel forming temperature can be characterized by rheology, the mechanical properties and the response to the applied strain can be obtained. In this thesis, we synthesized a series of hydrogels or organic gels based on NIPAM and studied the properties of these gels from the point of view of rheology. The main contents of this paper are as follows: in chapter 1, we introduce the gel materials based on NIPAM. Rheology and the basic concept of rheometer. The second chapter mainly deals with the random copolymerization of NIPAM and NEAM (N-ethylacrylamide) in different methanol-water mixed solvents. Their LCST and mechanical properties were characterized by temperature scanning and uniaxial compression tests. The hydrogels synthesized in the mixed solvent dominated by water have relatively good mechanical properties. In addition, the shear modulus measured by temperature scanning, the compression modulus measured by compression test and the Young's modulus measured by atomic force microscope can be compared. Because the three moduli have a similar trend with the methanol molar fraction of the solvent. In chapter 3, the rheological properties of P (NIPAM-co-NEAM) hydrogels with different comonomer components under the same conditions were studied by using the above method. The results show that the LCST and modulus decrease with the increase of NIPAM monomer content, which is due to the change of hydrophilic-hydrophobic equilibrium and pore size of the gel. In chapter 4, the rheological basis of PNIPAM organic gels dissolved in benzyl alcohol is studied. The results of temperature scanning show that PNIPAM samples with low isotacticity or concentration can not form gels during temperature scanning, so they do not have sol-gel conversion temperature. For other samples, their gel strength and sol-gel transition temperature are related to molecular weight, isotacticity and concentration. The linear viscoelastic limit of the organic gel tends to decrease with the increase of molecular weight, isotacticity and concentration. Chapter 5 deals with the large oscillatory shear scanning test of (NIBA), a supramolecular gel formed from the mixture of (NIDO), a copolymer of NIPAM and dopamine acrylamide, and (NIBA), a copolymer of NIPAM and 4-vinylphenylboric acid. The linear and nonlinear rheological behaviors of this material are different under different mixing ratios of two solutions. When the two polymer solutions are mixed at 1:1, the gel with the highest strength will be formed, while 4:1 mixture has obviously lower modulus and distinct rheological behavior. The ratio of the intensity of higher odd harmonic to the intensity of first harmonic can be obtained from the rheology of Fourier transformation, or the degree of distortion of Lissajous curve can be used to evaluate the degree of nonlinearity of materials. These supramolecular gels are different from general polymer melts and solutions. The nonlinearity of these supermolecular gels decreases when the strain is too large.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O648.17
本文编号：2244770
[Abstract]:The gel based on N-isopropylacrylamide (NIPAM) has a low critical dissolution temperature (LCST).) close to human body temperature. This property makes it a potential thermosensitive polymer gel material for drug delivery and biomedical engineering. Rheometer is an important tool for exploring soft matter materials such as gel, suspension and colloid in many instruments used to characterize gel. The gel forming temperature can be characterized by rheology, the mechanical properties and the response to the applied strain can be obtained. In this thesis, we synthesized a series of hydrogels or organic gels based on NIPAM and studied the properties of these gels from the point of view of rheology. The main contents of this paper are as follows: in chapter 1, we introduce the gel materials based on NIPAM. Rheology and the basic concept of rheometer. The second chapter mainly deals with the random copolymerization of NIPAM and NEAM (N-ethylacrylamide) in different methanol-water mixed solvents. Their LCST and mechanical properties were characterized by temperature scanning and uniaxial compression tests. The hydrogels synthesized in the mixed solvent dominated by water have relatively good mechanical properties. In addition, the shear modulus measured by temperature scanning, the compression modulus measured by compression test and the Young's modulus measured by atomic force microscope can be compared. Because the three moduli have a similar trend with the methanol molar fraction of the solvent. In chapter 3, the rheological properties of P (NIPAM-co-NEAM) hydrogels with different comonomer components under the same conditions were studied by using the above method. The results show that the LCST and modulus decrease with the increase of NIPAM monomer content, which is due to the change of hydrophilic-hydrophobic equilibrium and pore size of the gel. In chapter 4, the rheological basis of PNIPAM organic gels dissolved in benzyl alcohol is studied. The results of temperature scanning show that PNIPAM samples with low isotacticity or concentration can not form gels during temperature scanning, so they do not have sol-gel conversion temperature. For other samples, their gel strength and sol-gel transition temperature are related to molecular weight, isotacticity and concentration. The linear viscoelastic limit of the organic gel tends to decrease with the increase of molecular weight, isotacticity and concentration. Chapter 5 deals with the large oscillatory shear scanning test of (NIBA), a supramolecular gel formed from the mixture of (NIDO), a copolymer of NIPAM and dopamine acrylamide, and (NIBA), a copolymer of NIPAM and 4-vinylphenylboric acid. The linear and nonlinear rheological behaviors of this material are different under different mixing ratios of two solutions. When the two polymer solutions are mixed at 1:1, the gel with the highest strength will be formed, while 4:1 mixture has obviously lower modulus and distinct rheological behavior. The ratio of the intensity of higher odd harmonic to the intensity of first harmonic can be obtained from the rheology of Fourier transformation, or the degree of distortion of Lissajous curve can be used to evaluate the degree of nonlinearity of materials. These supramolecular gels are different from general polymer melts and solutions. The nonlinearity of these supermolecular gels decreases when the strain is too large.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O648.17
【参考文献】
相关期刊论文 前2条
1 Fumihiko Tanaka;Tsuyoshi Koga;Hiroyuki Kojima;Francoise M.Winnik;;HYDRATION AND PHASE SEPARATION OF TEMPERATURE-SENSITIVE WATER-SOLUBLE POLYMERS[J];Chinese Journal of Polymer Science;2011年01期
2 刘文博;王国明;蔡晴;金日光;;N-异丙基丙烯酰胺类共聚物温敏性研究[J];高分子学报;2008年12期
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