Study on Control of Liquid Crystal formation for Optically Anisotropic Films Synthesized from Chitin

点击翻译按钮获取中文摘要

From the previous our study, the following knowledge was obtained that microcrystalline chitin (MC), which is moderately hydrolyzed in aqueous hydrochloric acid, has NH3+ and shows chiral-nematic liquid crystalline structure in both aqueous suspension and including acrylic acid monomer, where isotropic, anisotropic and birefringence phases are found. The orientation was induced by placing in magnetic field or applying shear strength. The composite polymers made from the orientated suspension still had an orientation. From the polarized FT- IR analysis, glucose ring was orientating 90°, amide and NH groups were orientating 0° against magnetic field direction. When orientated by shear strength, glucose ring was orientating 0°, amide and NH groups were orientating 90° against shear direction, which was totally opposite when applying magnetic field.The present study is focusing on controlling LC formation of the above synthesized composite. In the course of studying 2D FT-IR of composite, it is known that the chitin structure is changing with the increase of temperature. The 2D FT-IR spectrum of orientated LC film was investigated. We can observe the state of hydrogen bonding(HB) and the sequence of breaking HB occurred in the order of [O(6)H... O(6)] of intermolecular hydrogen bonding, and [O(6')H...O(7)], [O(3')H...O(5)] of intramolecular HB with the increase of temperature. These results corresponds with X ray diffraction analysis.The structure of β chitin is similarly analyzed. It can be assigned that 3515 and 3376cm-1 are derived intermolecular HB of C(6)OH, 3342cm-1 the intramolecular HB of C(3)OH, 3617 and 1567cm-1 are due to free C(3)OH and C(6)OH, respectively.