Fundamental Study on Organoclay Nanocomposites Based on Functionalized Block Copolymer, Functionalized Liquid-Crystalline Polymer, and Functionalized Polynorbornene

研究：与实现高度剥离的有机粘土纳米复合材料的原理和机制有关的基本问题将被调查。通过阴离子聚合和羟化/氧化反应合成端基为C的二烯基ABC型三嵌段共聚物，通过缩聚反应合成功能化热致液晶聚合物(TLCP)，通过开环歧化聚合合成含羟基、乙酸基或胺基的官能化聚降冰片烯(PNB)。然后，每一种聚合物都将通过使用微型双螺杆复合机熔融混合，与经过化学修饰的有机粘土或有机碳纳米颗粒混合，以产生高度剥离的纳米复合材料。与传统的苯乙烯-丁二烯-丁二烯共聚物(SB橡胶)相比，以双烯为基础、端嵌段功能化的ABC型三嵌段弹性体的优势在于，通过合理地控制ABC型三嵌段共聚物中双烯嵌段的微观结构，可以通过极高的剥离度来大大提高纳米复合材料的力学性能。基本前提是在有机粘土或有机碳纳米颗粒与聚合物基质之间提供有吸引力的相互作用：功能化的ABC型三嵌段共聚物、官能化的TLCP或官能化的PNB。有吸引力的相互作用的存在将使用原位傅里叶变换红外光谱进行测试。用X射线衍射仪、透射电子显微镜和振荡剪切流变仪测试剥离程度，并研究纳米复合材料的力学性能(拉伸强度、撕裂强度、动态弹性系数和冲击强度)。研究这些纳米复合材料的形成、结构和动力学可以更好地理解与获得高度剥离的有机粘土纳米复合材料相关的原理和机制，并有可能开发新型纳米复合材料。从这一研究项目中产生的基本概念将有助于其他研究人员通过设计和合成新的聚合物体系或合成可用于修饰层状硅酸盐或石墨表面的新的表面活性剂来开发新的纳米复合材料。更广泛的影响：这些活动产生的更广泛的影响在于两个领域：(I)它将激励其他研究人员在坚实的科学基础上开发新一代纳米复合材料，(Ii)它将有助于为美国聚合物加工业开辟新的途径，以生产出具有吸引力和成本效益的新型纳米复合材料，以及(Iii)它将帮助价值400亿美元的美国轮胎制造业创新/改变现有的制造工艺，以提高轮胎的撕裂强度和滚动阻力。

ABSTRACTPI: Chang D. Han Institution: University of AkronProposal Number: 0406752Research: Fundamental issues concerning the principles and mechanisms associated with achieving a highly-exfoliated organoclay nanocomposite will be investigated. Diene-based ABC-type triblock copolymers with a functional group in the endblock C will be synthesized via anionic polymerization followed by hydroxylation/oxidation reactions, a functionalized thermotropic liquid-crystalline polymer (TLCP) will be synthesized via condensation polymerization, and functionalized polynorbornenes (PNB) with hydroxyl, acetic, or amine groups will be synthesized via ring opening metathesis polymerization. Then each of the polymers will be mixed, via melt blending using a micro twin-screw compounder, with chemically-modified organoclay or oganocardbon nanoparticles to produce nanocomposites with a high degree of exfoliation. Diene-based, endblock-functionalized ABC-type triblock elastomers have advantages over the conventional styrene-ran-butadiene copolymers (SB rubber) in that greatly improved mechanical properties, via a very high degree of exfoliation, of the nanocomposites can be obtained by judiciously controlling the microstructure of the diene block in an ABC-typle triblock copolymer. The basic premise is to provide attractive interactions between the organoclay or organocarbon nanoparticles and the polymer matrix: functionalized ABC-type triblock copolymer, functionalized TLCP, or functionalized PNB. The presence of attractive interactions will be tested using in-situ Fourier transform infrared spectroscopy. The degree of exfoliation will be tested using X-ray diffraction, transmission electron microscopy, and oscillatory shear rheometry, and the mechanical properties (tensile strength, tear strength, dynamic modulus, and impact strength) of the nanocomposites will be investigated. Investigation of the formation, structure, and dynamics of these nanocomposites can lead to a better understanding of the principles and mechanisms associated with achieving highly-exfoliated organoclay nanocomposites, and potentially to the development of novel nanocomposite materials.The fundamental concepts that will be developed from this research project should help other researchers to develop new nanocomposites either by designing and synthesizing new polymer systems or synthesizing new surfactants that can be used to modify the surfaces of layered silicates or graphite. Broader Impacts: The broader impacts resulting from these activities lie in two areas: (i) it will stimulate other researchers to develop new generations of nanocomposites on the basis of sound scientific foundations, (ii) it will help open avenues for the U.S. polymer fabrication industry to produce new attractive and cost-effective novel nanocomposites, and (iii) it will help the $40 billion U.S. tire manufacturing industry to innovate/alter the existing manufacturing processes for improved tear strength and rolling resistance of tires.