A series of monomers {2,5-bis[(5-alkyl-phenyl)-1,3,4-oxadiazole] styrene}(BOXE) were designed and synthesized.By radical polymerization initiated BPO with a novel series of mesogen-jacketed polymers containing 1,3,4-o...A series of monomers {2,5-bis[(5-alkyl-phenyl)-1,3,4-oxadiazole] styrene}(BOXE) were designed and synthesized.By radical polymerization initiated BPO with a novel series of mesogen-jacketed polymers containing 1,3,4-oxadiazole were prepared.Molecular weight and molecular weight distribution of polymers were measured by GPC.The glass transition temperature (T_g) and thermal stability of polymers were studied by DSC and TGA.The results indicate that these polymers have good thermal stability.These liquid crystal polymers have well defined structure,and possess special photo-electronic properties.展开更多
The synthesis of rod-coil diblock copolymers was achieved for the first time by TEMPO-mediated 'living' free radical polymerization of styrene and 2,5-bis [(4-methoxyphenyl)oxycarbonyl] styrene(MPCS). The blo...The synthesis of rod-coil diblock copolymers was achieved for the first time by TEMPO-mediated 'living' free radical polymerization of styrene and 2,5-bis [(4-methoxyphenyl)oxycarbonyl] styrene(MPCS). The block architecture of the two diblock copolymers thus prepared, MPCS-b-St(5400/2400) and MPCS-b-St(10800/8700), was confirmed by GPC, DSC studies and the formation of multimolecular micelles. (Author abstract) 10 Refs.展开更多
The first TEMPO-mediated 'living' free radical polymerization of liquid crystalline monomer, 2, 5-bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS), was carried out at 130 degrees C with BPO as an initiator. The...The first TEMPO-mediated 'living' free radical polymerization of liquid crystalline monomer, 2, 5-bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS), was carried out at 130 degrees C with BPO as an initiator. The molecular weight of the polymer can be varied from rather low values to high values while maintaining narrow polydispersity. It was observed that the polymerization of MPCS proceeded much faster than that of styrene. A tentative explanation for this fast polymerization was suggested.展开更多
Poly{2, 5-bis[(p-methoxyphenyl)oxycarbonyl]styrene} was successfully synthesized. This new polymer has a structure characteristic of mesogen-jacketed liquid cyrstalline polymers (MJLCPs) and does form a liquid crystal...Poly{2, 5-bis[(p-methoxyphenyl)oxycarbonyl]styrene} was successfully synthesized. This new polymer has a structure characteristic of mesogen-jacketed liquid cyrstalline polymers (MJLCPs) and does form a liquid crystal phase above its glass transition. It thus became the starting member of a new series of MJLCPs. The synthesis of the polymer as well as the liquid crystalline properties of the polymer and its monomer was discussed. A brief comparison of the new monomer and polymer with some previously reported counterparts was also included.展开更多
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
文摘A series of monomers {2,5-bis[(5-alkyl-phenyl)-1,3,4-oxadiazole] styrene}(BOXE) were designed and synthesized.By radical polymerization initiated BPO with a novel series of mesogen-jacketed polymers containing 1,3,4-oxadiazole were prepared.Molecular weight and molecular weight distribution of polymers were measured by GPC.The glass transition temperature (T_g) and thermal stability of polymers were studied by DSC and TGA.The results indicate that these polymers have good thermal stability.These liquid crystal polymers have well defined structure,and possess special photo-electronic properties.
基金This project was supported by the Foundation of Peking University for Young Scientist and the National Natural Science Foundation of China.
文摘The synthesis of rod-coil diblock copolymers was achieved for the first time by TEMPO-mediated 'living' free radical polymerization of styrene and 2,5-bis [(4-methoxyphenyl)oxycarbonyl] styrene(MPCS). The block architecture of the two diblock copolymers thus prepared, MPCS-b-St(5400/2400) and MPCS-b-St(10800/8700), was confirmed by GPC, DSC studies and the formation of multimolecular micelles. (Author abstract) 10 Refs.
基金This work was supported by the Foundation of Peking University for Young Scientist and the National Natural Science Foundation of China(Grant No.29874003).
文摘The first TEMPO-mediated 'living' free radical polymerization of liquid crystalline monomer, 2, 5-bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS), was carried out at 130 degrees C with BPO as an initiator. The molecular weight of the polymer can be varied from rather low values to high values while maintaining narrow polydispersity. It was observed that the polymerization of MPCS proceeded much faster than that of styrene. A tentative explanation for this fast polymerization was suggested.
基金This work is supported by the National Natural Science Foundation of China.
文摘Poly{2, 5-bis[(p-methoxyphenyl)oxycarbonyl]styrene} was successfully synthesized. This new polymer has a structure characteristic of mesogen-jacketed liquid cyrstalline polymers (MJLCPs) and does form a liquid crystal phase above its glass transition. It thus became the starting member of a new series of MJLCPs. The synthesis of the polymer as well as the liquid crystalline properties of the polymer and its monomer was discussed. A brief comparison of the new monomer and polymer with some previously reported counterparts was also included.
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]
