Synthesis of Poly(1,3-cyclohexadiene) Containing Star-Shaped Elastomers |
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Authors: | D.T. Williamson T.E. Long |
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Affiliation: | Virginia Polytechnic University and State University, Department of Chemistry, Polymer Materials and Interfaces Laboratories, Blacksburg, VA 24061-0212, USA |
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Abstract: | The synthesis of high molecular weight star-shaped polymers comprising poly(1,3-cyclohexadiene-block-isoprene) diblock arms coupled to a divinyl benzene (DVB) core is reported. The number average molecular weights of the diblock arms were varied from 30000 to 50000 and the ratio of DVB to n-butyllithium (nBuLi) was systematically varied from 3:1 to 12:1. Size exclusion chromatography coupled with light scattering detection was utilized to detect the formation of star-shaped polymers and the presence of star-star coupling. The molecular weight distribution (w>/n>) of the star polymers ranged from 1.25 to 1.50. The effect of poly(1,3-cyclohexadiene) content on the mechanical properties of these novel elastomers is reported. The elastic modulus, elongation at break, and tensile strength of these elastomers were all found to be a function of the percentage of poly(1,3-cyclohexadiene). The glass transition temperatures were determined using both differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Atomic force microscopy was performed in the tapping mode (TMAFM) to verify the presence of microphase separation. |
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Keywords: | anionic polymerization atomic force microscopy 1,3-cyclohexadiene star-shaped polymer thermoplastic elastomer |
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