Crosslinked liquid crystalline film cast from hydroxypropyl cellulose/methanol liquid crystalline solution.

Abstract

Crosslinked hydroxypropyl cellulose (HPC) films were cast from liquid crystalline HPC/methanol solution with p-formaldehyde (p-FA) in the presence of hydrochloric acid. Whether or not crosslinked liquid crystalline structures were retained in the cast films was examined by polarized microscopy and circular dichroic (CD) spectroscopy. The dependence of tensile and dynamic mechanical properties of solid films on crosslinking agent concentration was determined. The films were not soluble in both water and methanol. and hence it was proved that the films had been crosslinked. From polarized microscopic observation and CD spectrum, it was found that the HPC solid films retained right-handed helicoidal cholesteric structures. Small-angle light scattering (SALS) patterns of the insoluble films were not affected by addition of crosslinking agent, but were affected by the band textures. With respect to tensile properties. Young's modulus increased with crosslinking agent concentration, and tensile strength and elongation had opposite tendencies to Young's modulus. In dynamic mechanical properties. E' increased with crosslinking agent concentration and exhibited general behaviors of crosslinked materials.