Polyacrylonitrile (PAN) fibers containing 10 wt.‐% single‐walled carbon nanotubes (SWNTs) exhibit a 100 % improvement in tensile modulus and reduced thermal shrinkage and polymer solubility. A 40 °C increase in glass transition temperature as compared to the control PAN fiber is also observed (see Figure). SWNT anisotropy has been observed using infrared spectroscopy.

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Reinforcement efficiency of different types of carbon nanotubes (CNT) have been compared in polyacrylonitrile (PAN) films at nanotube loadings of 5, 10, and 20 wt %. The films are characterized for mechanical, dynamic-mechanical, and thermomechanical properties, electrical conductivity, as well as structural analysis. PAN/CNT composite films exhibit electrical conductivities up to 5500 S/m. Based on X-ray diffraction, PAN crystallinity was shown to increase with the presence of CNT. PAN-CNT interactions in the various composites were compared using conventional activation energy analysis. The strongest physical interaction between PAN and CNT was found in samples containing single-wall carbon nanotubes (SWNT). CNT surface area was also measured using nitrogen gas adsorption and correlated with PAN-CNT composite film mechanical properties, in an effort to better understand PAN-CNT interactions for different CNT morphologies. Solvent behavior of various composite films has also been investigated. The presence of CNT was found to improve PAN solvent resistance.

An LCE with a p‐pentaphenyl transverse rod in the main chain was synthesized, in which the rod can be oriented parallel or normal to the main chain under uniaxial tension. DSC and WAXD studies indicate a highly ordered lamellar structure typical of a smectic A phase. Stress‐strain curves showed a large Young modulus at small strains, followed by a yield point, at which necking occurred and the specimen became transparent. An interesting rigid‐soft‐rigid phenomenon was observed in the yield section, which is likely to indicate a self‐assembly‐driven reconstruction process. Two possible arrangements of transverse rods and chain extenders are proposed for the network structure.magnified image

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