Study on mesomorphic properties of side-china cholesteric polymers and elastomers

The synthesis of side chain cholesteric liquid crystalline polymers (P-n series) and elastomers (P-n series) containing both 4-allyloxybenzoyleholeseterate ( M-ch) and 4-allyloxybenzoyloxy-4'-methoxyphenyI ( M-n) or 2-tert-buty-1-hydroquinone di (4-( b-acryloyloxy hexyloxy) benzoate) ( M-nc) mesogenic side groups was described. The chemical structures of the obtained polymers and elastomers were confirmed by FT-IR spectroscopy. Their mesomorphic properties and phase behavior were investigated with POM, DSC, TGA and X-ray measurements. The liquid crystalline polymers P-n1 similar to P-n8 and elastomers P-e1 similar to P-e7 exhibited cholesteric grandjean texture or oily streak texture. In P-n series, with increasing the concentration of the cholesteric mesogenic M-ch, the glass transition temperature( T-g) increased from 8.7degreesC to 65.7degreesC and the clearing point temperature( T-c) increased from 42.0degreesC to 251.8degreesC. In P-e series, with increasing the concentration of the nematic liquid crystalline crosslinking agent M-nc, T-g decreased from 65.7degreesC to 52.7degreesC and T-e had no significant change. When the concentration of M-nc was greater than 8 mol %, the DSC curves of P-e6 and P-e7 did not show the clearing point temperatures, but POM observations exhibited the grandjean texture, which did not disappear until their decomposition. The polymers P-n1 similar to P-n1 l and elastomers P-e1 similar to P-e7 had wide mesomoephic temperature ranges. TGA measurements showed that the temperature at which a 5% mass loss occurred was higher than 280degreesC for all the liquid crystalline polymers and ealastomers.