【作者】 靳磊；

【导师】 杨亚江；

【作者基本信息】 华中科技大学 ， 高分子化学与物理， 2013， 博士

【摘要】 超分子化学是研究基于分子间的非共价键相互作用的化学。一般来说自组装的驱动力来源于分子间的相互作用，所以通常的自组装行为都是自发的，是不可控的。目前，通过外加声、光、电、磁、热、阴阳离子、氧化还原等手段，对于自组装行为的调控已经引起了广泛的关注。另外，将超分子聚集体引入高分子基体中可以原位增强聚合物材料的性能，相对于传统的纤维增强复合材料，分子复合材料已经显示出独特的优势。本文利用一种水性凝胶因子将三嵌段聚合物的水溶液凝胶化，通过调节温度使三嵌段聚合物的水溶液体系在特定的温度范围内转变为层状结构，诱导水性凝胶因子在其中发生三维向二维结构转变的自组装行为，从而达到了通过温度调控自组装行为的目的。通过将有机的凝胶因子聚集体和金属-有机复合物的聚集体引入聚氨酯基体中，制备了一系列分子复合材料，研究了超分子纤维分子增强的效果，探讨了凝胶因子聚集体分子增强聚合物的机理。本论文包括以下主要内容：1、本工作利用PEO-PPO-PEO三嵌段共聚物（PE6200）水溶液在特定温度下发生从各向同性的胶束相到各向异性的层状相转变的性质，以一种均苯四甲酸和对羟基吡啶（1:2）的双组份水性凝胶因子（简称为HB21）将体系凝胶化，研究了凝胶因子在PE6200水体系中的自组装行为。小角X射线散射（SAXS）结果表明，在低于50℃的温度范围，PE6200水体系为各向同性液体状态，凝胶因子在此体系中自组装形成稳定的三维网络结构。而在50-60℃时，由于PE6200转变为层状相结构，凝胶因子在亲水性和体系熵稳定性的共同作用下，在PE6200极化区域的富水层中转变成为二维自组装结构。差示量热扫描（DSC）、变温拉曼光谱和电化学循环伏安法的表征，进一步证实了在这个温度范围下的相转变行为。这些研究表明，凝胶因子从三维到二维自组装的转变是一种热力学控制的过程，由此提出了一种利用嵌段共聚物相行为的热力学可控自组装的新策略。2、在常规聚合物前体树脂（改性聚氨酯齐聚物SM6202）中引入凝胶因子1,3;2,4-二亚苄叉山梨醇（DBS）自组装形成的纳米纤维状聚集体，利用分子复合的原理，首先使聚合物前体树脂凝胶化，随后通过光引发聚合，制备了分子复合聚合物，实现对聚合物的增强。研究结果表明DBS在齐聚物基体树脂中有良好的凝胶性能，并且通过SEM表征证实DBS自组装形成了纳米纤维状超分子聚集体。通过测定不同浓度的DBS聚集体与改性聚氨酯形成的分子复合材料的应力应变曲线，发现由于DBS的加入，使树脂的断裂伸长率以及拉伸断裂强度都显著提高，其中断裂伸长率由31%增加到45%，增幅为50%，拉伸断裂强度由1.4MPa增加到4.2MPa，增幅为200%。即当DBS加入，基体树脂在宏观上表现为既增韧又增强的性质。同时通过动态力学热分析（DMA）研究，表征了凝胶因子DBS分子聚集体的加入对于复合材料内在模量以及体系玻璃化温度的影响。另外通过比重与透明性测试表明，DBS聚集体原位增强的复合材料在增强力学性能的同时，仍然能够保持高分子材料比重轻与透明度高的特性，体现了分子复合材料相比传统的宏观纤维增强材料的优势。3、利用Fe(Ⅲ)与癸二酸形成的复合物（简称为Fe(SA)），并将其引入改性聚氨酯齐聚物（SM6202）中使其凝胶化，随后通过光引发聚合，制备了分子复合聚合物，实现对聚合物的增强。SEM测试结果表明Fe(SA)可以形成内含卷曲薄片状的球状聚集体结构，并且通过拉伸断裂测试得到含有Fe(SA)的聚氨酯复合材料的断裂伸长率以及拉伸断裂强度都显著提高，其中拉伸断裂强度由1.4MPa增加到4.3MPa，增幅为207%；断裂伸长率由31%增加到53%，增幅为71%。即当Fe(SA)加入，基体树脂在宏观上表现为既增韧又增强的性质。同时同时通过动态力学热分析（DMA）研究，表明Fe(SA)聚集体的加入可以增加聚合物的储能模量，并且使玻璃化温度上升。另外通过比重和透明度的分析，也证实了Fe(SA)聚集体分子增强材料在增加力学性能的同时仍能保持高分子材料比重轻和透明度高的特性，相对于无机的纳米颗粒填料，体现了分子复合材料的优势。更多还原

【Abstract】 Supramolecular chemistry is the chemistry that focus on intermolecular non-covalentinteractions. The driving force of self-assembly generally comes from intermolecularnon-covalent interactions. So usually self-assembly behaviors are all spontaneous anduncontrollable. Stable supramolecular gels can be formed through solvent moleculeswhich bound in the network. Nowadays, the regulation of self-assembly behavior byapplying sound, light, electricity, magnetism, heat, ions, redox and other means has causedwidespread concern. In addition, the performance of the polymer material can be enhancedin situ by introducing supramolecular aggregates into the polymer matrix. Molecularcomposite has shown a unique advantage which has been compared with traditionalfiber-reinforced composites.The aqueous solution of the triblock polymer can be gelled by taking advantage ofhydrogelator. The hydrogelator aggregates phase behaviour can be turned from3D to2Dwhile the aqueous solution of the triblock polymer bacome lamellar structure within aspecific temperature range. So the self-assembly behaviour of hydrogelator can becontrolled by tuning the temperature. A series of molecular composites were prepared byintroducing organic gelator and organic-metal aggregates into polyurethane matrix. Themolecular reinforce effect and the mechanism of gelator aggregates enhance polymer wasstudied.This thesis is consisted of several sections as the following:1. This work took advantage of the PEO-PPO-PEO three block copolymer aqueoussolution (PE6200) which had phase transition properties that from isotropy micellar phaseto anisotropic lamellar at specific temperatures. The self-assembly behavior of gelator inPE6200water system was studied by introducing the hydrogelator (HB21) that contains1,2,4,5-benzenetetracarboxylic acid and4-hydroxypyridine (1:2) into the aqueous system. Small Angle X-ray scattering (SAXS) results showed that PE6200water system becameisotropic liquid, gelator self-assembled to form stable three-dimensional network structure,in the temperature range less than50℃. While warned up to50~60℃, gelatoraggregates transformed into two-dimensional self-assembly structures in PE6200polarized area rich in water, beause the hydrophilic factor and the stability of the systementropy PE6200into lamellar structure. Scanning differential calorimeter (DSC), variabletemperature Raman spectroscopy and electrochemical cyclic voltammetry characterization,further confirmed the phase transition behavior in the temperature range. These resultssuggest that gelator from3D to2D self-assembly is a process of thermodynamiccontrolled. Thus put forward a way to tune self-assembly behaviour by taking advantageof thermodynamics controllable block copolymer.2. Nanometer fibrous aggregates which formed by organic gelator1,3:2,4-Dibenzylidene sorbitol (DBS) were introduced into a conventional modifiedpolyurethane resin (SM6202). Through the principle of molecular composite, organicgelator DBS gelled the precursor polymer resin first and then the gel polymerized by UVinitiate to prepare molecular composite polymer. The results showed that DBS in theoligomer matrix resin had excellent gelation performance, DBS supramolecularaggregates formed nano fibrous confirmed by SEM. The elongation at break and tensilefracture strength of composites increased significantly, which was demonstrated bystress-strain curve of composite material that contained DBS aggregate and modifiedpolyurethane. The elongation at break increased from31%to45%with a growth of50%,the tensile breaking strength increased from1.4MPa to4.2MPa with a growth of200%.The composites material with DBS became toughening and strengthening on themacroscopic. The influence of inherent modulus of the composite material and glasstransition temperature of the system with DBS aggregates were characterized by dynamicmechanical thermal analysis (DMA). In addition, the specific gravity and transparency testshowed that DBS composites in situ not only enhanced mechanical properties but also maintained the characteristics of light weight and high transparency of polymer materials.The results demonstrated the unique advantages which compared to the traditionalmacro-fiber composites.3. Polyurethane oligomer (SM6202) was gelled by Fe(Ⅲ) and sebacic acid whichformed compounds Fe(SA). The preparation of molecular composite polymer was carriedout by UV-light initiate. The SEM results showed that the Fe(SA) became sphericalaggregates which formed by curly lamellar. The elongation at break and tensile fracturestrength of polyurethane composites were improved significantly. The elongation at breakincreased from31%to53%with a growth of71%, the tensile breaking strength increasedfrom1.4MPa to4.3MPa with a growth of207%. The composite material bacametoughening and strengthening on the macroscopic. The storage modulus and glasstransition temperature of Fe(SA) composites increaseed which was confirmed by dynamicmechanical thermal analysis (DMA). In addition, the specific gravity and transparency testshowed that Fe(SA) composites in situ not only enhanced mechanical properties but alsomaintained the characteristics of light weight and high transparency of polymer materials.The results demonstrated the unique advantages which compared to the nano-particulatefiller.更多还原