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

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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.