This paper describes the synthesis and free radical polymerization of 2,5 bis(4′ alkyloxyphenyl)styrene(M n ) for mesogen jacketed liquid crystal polymers(MJLCPs), where p terphenyl subsituted by alkoxy groups at bot...This paper describes the synthesis and free radical polymerization of 2,5 bis(4′ alkyloxyphenyl)styrene(M n ) for mesogen jacketed liquid crystal polymers(MJLCPs), where p terphenyl subsituted by alkoxy groups at both ends was used as mesogenic unit. Because of the absence of the polar linkage groups, such as —COO— or —CONH— as employed in the previous reported MJLCPs, M n is believed to be polymerized easily by both free radical polymerization and ionic polymerization. The chemical structure of M n was proved by 1H NMR, mass spectrometry and elementary analysis. Their phase transition and liquid crystallinity were characterized by DSC and POM. Although M 1, M 2, M 3 and M 4 exhibited monotropic nematic mesophase, M 5 displayed enantiotropic nematic mesophase presumably because of its decreased melting transition temperature. All monomers were easily polymerized to moderately high molecular weight polymers. At elevated temperature above T g, poly[2,5 bis(4′ alkoxyphenyl)styrene] showed a very stable mesophase. The formed birefrigence did not disappear until thermal decomposition started. Compared to other MJLCPs, the polymers reported here have much higher thermal stability. [WT5HZ]展开更多
Two monomers of 2,5 bis[( p methoxyphenoxy)carbonyl]benzyl acrylate and 2,5 bis[( p methoxyphenoxy)carbonyl] benzyl methacrylate and their corresponding polymers were successfully synthesized. The mesomorphic behavior...Two monomers of 2,5 bis[( p methoxyphenoxy)carbonyl]benzyl acrylate and 2,5 bis[( p methoxyphenoxy)carbonyl] benzyl methacrylate and their corresponding polymers were successfully synthesized. The mesomorphic behavior of both polymers was examined by using differential scanning calorimetry(DSC) and polarized optical microscopy(POM). It was found that both polymers are noncrystalline with a glass transition temperature of 67.1 ℃ for poly {2,5 bis[( p methoxyphenoxy)carbonyl]benzyl acrylate} and 95.1 ℃ for poly {2,5 bis[( p methoxyphenoxy)carbonyl]benzyl methacrylate}, above which the former can form liquid crystalline state and the clearing temperature is 97.8 ℃ while the latter can not. This indicates that main chain rigidity will affect the liquid crystallinity of mesogen jacketed polymers.展开更多
文摘This paper describes the synthesis and free radical polymerization of 2,5 bis(4′ alkyloxyphenyl)styrene(M n ) for mesogen jacketed liquid crystal polymers(MJLCPs), where p terphenyl subsituted by alkoxy groups at both ends was used as mesogenic unit. Because of the absence of the polar linkage groups, such as —COO— or —CONH— as employed in the previous reported MJLCPs, M n is believed to be polymerized easily by both free radical polymerization and ionic polymerization. The chemical structure of M n was proved by 1H NMR, mass spectrometry and elementary analysis. Their phase transition and liquid crystallinity were characterized by DSC and POM. Although M 1, M 2, M 3 and M 4 exhibited monotropic nematic mesophase, M 5 displayed enantiotropic nematic mesophase presumably because of its decreased melting transition temperature. All monomers were easily polymerized to moderately high molecular weight polymers. At elevated temperature above T g, poly[2,5 bis(4′ alkoxyphenyl)styrene] showed a very stable mesophase. The formed birefrigence did not disappear until thermal decomposition started. Compared to other MJLCPs, the polymers reported here have much higher thermal stability. [WT5HZ]
文摘Two monomers of 2,5 bis[( p methoxyphenoxy)carbonyl]benzyl acrylate and 2,5 bis[( p methoxyphenoxy)carbonyl] benzyl methacrylate and their corresponding polymers were successfully synthesized. The mesomorphic behavior of both polymers was examined by using differential scanning calorimetry(DSC) and polarized optical microscopy(POM). It was found that both polymers are noncrystalline with a glass transition temperature of 67.1 ℃ for poly {2,5 bis[( p methoxyphenoxy)carbonyl]benzyl acrylate} and 95.1 ℃ for poly {2,5 bis[( p methoxyphenoxy)carbonyl]benzyl methacrylate}, above which the former can form liquid crystalline state and the clearing temperature is 97.8 ℃ while the latter can not. This indicates that main chain rigidity will affect the liquid crystallinity of mesogen jacketed polymers.
