A mesogen-jacketed liquid crystal polymer,poly{2,5 -bis［(4′-hexyloxyphenyl)oxycarbonyl］styrene}(PHPCS),with number-average d molecular weight of 1.28×１０5 and polydispersity of 1.48 was prepared vi a 2,2,6,6 ...A mesogen-jacketed liquid crystal polymer,poly{2,5 -bis［(4′-hexyloxyphenyl)oxycarbonyl］styrene}(PHPCS),with number-average d molecular weight of 1.28×１０5 and polydispersity of 1.48 was prepared vi a 2,2,6,6 -tetramethyl-piperidinyloxy mediated free radical polymerization.The thermotr opic behavior was studied by a combination of differential scanning calorimetry, thermogravimetry,polarized optical microscope and wide-angle X-ray diffracti on.PHPCS was not crystalline over the entire temperature region studied.On hea ting,PHPCS first became an isotropic melt at glass transition temperature (T g) and then a mesophase at temperatures much higher than T g.On subseq uent cooling,the formed ordered phase disappeared above T g.Contrary to t heoretical predictions and previous experimental observations,the transition fr om isotropic melt to liquid crystalline phase was an endothermic process and th e order-disorder transition took place with concurrence of heat release.展开更多
Butyryl chitosan was synthesized and characterized by using FTIR, DSC, WAXD and PLM. Liquid crystallinity of butyryl chitosan was first reported in this paper. Comparing with chitosan, thermal stability and crystallin...Butyryl chitosan was synthesized and characterized by using FTIR, DSC, WAXD and PLM. Liquid crystallinity of butyryl chitosan was first reported in this paper. Comparing with chitosan, thermal stability and crystallinity of butyryl chitosan decreased but solubility increased, because hydrogen bond interactions between macromolecules were disrupted.展开更多
Two liquid crystal monomers,cholesteryl 10\|undecylenate (M1), and cholesteryl 4\|(10\|undecylenoyloxy)\|benzoate(M2),and their respective side\|chain liquid crystal homopolymers (P1,P2) were synthesized.Their liquid ...Two liquid crystal monomers,cholesteryl 10\|undecylenate (M1), and cholesteryl 4\|(10\|undecylenoyloxy)\|benzoate(M2),and their respective side\|chain liquid crystal homopolymers (P1,P2) were synthesized.Their liquid crystal properties were characterized by POM and DSC method.M1 could form sematic liquid crystal and cholesteric liquid crystal,while M2\|only cholesteric liquid crystal.The Polymers,P1 and P2,exhibited sematic liquid crystal behavior.The results also indicated that,because of the structure of 1,4\|COO\|Ar\|COO\|in M2 and P2,the isotropization tempretures of the liquid crystalline M2 and P2 were higher than those of M1 and P1,respectively,and the temprature range of LC phases of M2 was also wider than that of M1.Homopolymer P1,was applied in the capillary column gas chromatography as a novel stationary phase and showed ideal separating selectivity.A mixture of anthracene,phenanthrene and acenaphene and a mixture of dichlorobenzene isomers were well separated.展开更多
文摘A mesogen-jacketed liquid crystal polymer,poly{2,5 -bis［(4′-hexyloxyphenyl)oxycarbonyl］styrene}(PHPCS),with number-average d molecular weight of 1.28×１０5 and polydispersity of 1.48 was prepared vi a 2,2,6,6 -tetramethyl-piperidinyloxy mediated free radical polymerization.The thermotr opic behavior was studied by a combination of differential scanning calorimetry, thermogravimetry,polarized optical microscope and wide-angle X-ray diffracti on.PHPCS was not crystalline over the entire temperature region studied.On hea ting,PHPCS first became an isotropic melt at glass transition temperature (T g) and then a mesophase at temperatures much higher than T g.On subseq uent cooling,the formed ordered phase disappeared above T g.Contrary to t heoretical predictions and previous experimental observations,the transition fr om isotropic melt to liquid crystalline phase was an endothermic process and th e order-disorder transition took place with concurrence of heat release.
文摘Butyryl chitosan was synthesized and characterized by using FTIR, DSC, WAXD and PLM. Liquid crystallinity of butyryl chitosan was first reported in this paper. Comparing with chitosan, thermal stability and crystallinity of butyryl chitosan decreased but solubility increased, because hydrogen bond interactions between macromolecules were disrupted.
文摘Two liquid crystal monomers,cholesteryl 10\|undecylenate (M1), and cholesteryl 4\|(10\|undecylenoyloxy)\|benzoate(M2),and their respective side\|chain liquid crystal homopolymers (P1,P2) were synthesized.Their liquid crystal properties were characterized by POM and DSC method.M1 could form sematic liquid crystal and cholesteric liquid crystal,while M2\|only cholesteric liquid crystal.The Polymers,P1 and P2,exhibited sematic liquid crystal behavior.The results also indicated that,because of the structure of 1,4\|COO\|Ar\|COO\|in M2 and P2,the isotropization tempretures of the liquid crystalline M2 and P2 were higher than those of M1 and P1,respectively,and the temprature range of LC phases of M2 was also wider than that of M1.Homopolymer P1,was applied in the capillary column gas chromatography as a novel stationary phase and showed ideal separating selectivity.A mixture of anthracene,phenanthrene and acenaphene and a mixture of dichlorobenzene isomers were well separated.
