Three novel copolymers,poly[1-（4-（benzothiazole-2-thio-alkyloxy）-biphenyl-4＇-oxy）2.3-epoxypropane]s,were synthesized by the reaction of polyepichlorohydrin with obtained monomers,4-（benzothiazole-2-thio-alkyloxy...Three novel copolymers,poly[1-（4-（benzothiazole-2-thio-alkyloxy）-biphenyl-4＇-oxy）2.3-epoxypropane]s,were synthesized by the reaction of polyepichlorohydrin with obtained monomers,4-（benzothiazole-2-thio-alkyloxy）biphenyl-4＇-ols,in which the number of methylene unit in substitution group of biphenyl group was 2,4,6,respectively.The structures of obtained compounds were confirmed by elemental analysis and 1H NMR.The decomposition temperatures of copolymers were near 340 ℃.Differential scanning calorimetry（DSC） measurement and polarized optical microscopy（POM） observation showed the resulting copolymers did not exhibit thermotropic liquid crystalline mesomophism and belonged to semi-crystalline substance.展开更多
4,4＇-dibromo-2-nitro-biphenyl and 4,4＇-dibromo-2,3＇-dinitro-biphenyl have been synthesized via nitration reaction with 4,4＇-dibromobiphenyl as the raw material. Three novel thiophene derivatives, 4, 4＇-di（4-hexy...4,4＇-dibromo-2-nitro-biphenyl and 4,4＇-dibromo-2,3＇-dinitro-biphenyl have been synthesized via nitration reaction with 4,4＇-dibromobiphenyl as the raw material. Three novel thiophene derivatives, 4, 4＇-di（4-hexyl-thiophen-2-yl）biphenyl, 4,4＇-di（4-hexyl-thiophen-2-yl）-2- nitro-biphenyl and 4,4＇-di（4- hexyl-thiophen-2-yl）-2,3＇-dinitrobiphenyl were synthesized through Stille coupling reaction, followed by polymerization in the presence of FeC13, respectively. UV-vis absorption spectra, fluorescence spectra, photoluminescence spectra and electrochemical properties of the polymers were investigated. And the band-gap （Eg）, HOMO orbital energy （EHCMO）, and LUMO orbital energy （EUJMO） of the polymers were calculated. Among the polymers, polymer PBTN and PBTD show lower band-gap （2.67 and 2.63 eV）, lower HOMO energy level （-5.38 and -5.4 eV） and broader wavelength （432 and 438 nm） than that of polymer PBTB （2.69 eV, -5.36 eV and 424 nm） with incorporation of one nitro group or two nitro groups in the main chain, respectively.展开更多
A novel polyimide(PI) containing pendent biphenyl ester groups was synthesized from 3,5-diaminobenzoic-4′-biphenyl ester (DABBE)and 3,3′,4,4′-oxydiphthalic dianhydride(ODPA) by a one-step high-temperature polyconde...A novel polyimide(PI) containing pendent biphenyl ester groups was synthesized from 3,5-diaminobenzoic-4′-biphenyl ester (DABBE)and 3,3′,4,4′-oxydiphthalic dianhydride(ODPA) by a one-step high-temperature polycondensation in m-cresol.This PI is a semicrystalline polymer.Lots of short fine fibric crystals with length and diameter about 20、μm and 1、μm respectively disperse randomly in the PI film. The optical textures and the X-ray diffraction patterns of the PI solution and film show that the PI main chains are in the extended conformation and pack parallel to each other, and the pendent biphenyl ester groups occupy the space between the main chain layers,more or less perpendicular to the main chains.At the same time, mechanical and thermally stable properties of the PI film were investigated. The excellent mechanical properties of general polyimide films are reasonably maintained, the polyimide film with pendent groups showes higher tensile strength and modulus and lower T g. TGA study showes a typical two-step weight loss behavior corresponding to the pyrolysis of pendent groups and main chains of the PI,respectively.展开更多
Biphenyl-contained monomer of 1,4-bis[2-（3,4-epoxy cyclohexyl ethyl） dimethylsilyl] biphenyl （BP-SiH-EP） was prepared via hydrosilylation reaction of 1,4-bis（dimethylsilyl） biphenyl （BP-SiH） and 1,2-epoxy-4-vi...Biphenyl-contained monomer of 1,4-bis[2-（3,4-epoxy cyclohexyl ethyl） dimethylsilyl] biphenyl （BP-SiH-EP） was prepared via hydrosilylation reaction of 1,4-bis（dimethylsilyl） biphenyl （BP-SiH） and 1,2-epoxy-4-vinylcyclohexane in the presence of Karstedt＇s catalyst. ^1H-NMR, 13C-NMR and FTIR were used to characterize the structure of the obtained monomer. BP-SiH-EP was then cured by methyl hexahydrophthalic anhydride （MeHHPA） with 1-cyanoethyl-2-ethyl-4- methylimidazole as an accelerator. The polymerization behavior was studied by DSC. The results of DMA measurement demonstrate that the cured BP-SiH-EP/MeHHPA can maintain high storage modulus （〉1 GPa） in a wide range of temperature up to 176 ℃. According to the damping factor curve of DMA, cured BP-SiH-EP/MeHHPA exhibits a high glass transition temperature （Tg） of 192 ℃, which is 20 ℃ higher than that of cured 1,4-bis[2-（3,4-epoxy cyclohexyl ethyl） dimethylsilyl] benzene （DEDSB）/MeHHPA. TGA results show that cured BP-SiH-EP/MeHHPA has good thermal stability （Tso/o = 339 ℃） due to the high heat-resistance of rigid biphenyl group. Moreover, the crosslinking density of cured BP-SiH-EP/MeHHPA should be lower than that of cured DEDSB/MeHHPA estimated from their chemical structures, which conflicts with the calculated results based on the rubber elasticity equation. The inconsistence indicates that the calculated crosslinking densities are not comparable, possibly owing to their differences in the rigidity of polymer chains and intermolecular interaction.展开更多
基金Funded by the National Natural Science Foundation of China (No.200474049)Specialized Research Fund for the Doctoral Program of Higher Education of China (No.20040497001)
文摘Three novel copolymers,poly[1-（4-（benzothiazole-2-thio-alkyloxy）-biphenyl-4＇-oxy）2.3-epoxypropane]s,were synthesized by the reaction of polyepichlorohydrin with obtained monomers,4-（benzothiazole-2-thio-alkyloxy）biphenyl-4＇-ols,in which the number of methylene unit in substitution group of biphenyl group was 2,4,6,respectively.The structures of obtained compounds were confirmed by elemental analysis and 1H NMR.The decomposition temperatures of copolymers were near 340 ℃.Differential scanning calorimetry（DSC） measurement and polarized optical microscopy（POM） observation showed the resulting copolymers did not exhibit thermotropic liquid crystalline mesomophism and belonged to semi-crystalline substance.
基金Supported by the National Natural Science Foundation of China(No.21176193)
文摘4,4＇-dibromo-2-nitro-biphenyl and 4,4＇-dibromo-2,3＇-dinitro-biphenyl have been synthesized via nitration reaction with 4,4＇-dibromobiphenyl as the raw material. Three novel thiophene derivatives, 4, 4＇-di（4-hexyl-thiophen-2-yl）biphenyl, 4,4＇-di（4-hexyl-thiophen-2-yl）-2- nitro-biphenyl and 4,4＇-di（4- hexyl-thiophen-2-yl）-2,3＇-dinitrobiphenyl were synthesized through Stille coupling reaction, followed by polymerization in the presence of FeC13, respectively. UV-vis absorption spectra, fluorescence spectra, photoluminescence spectra and electrochemical properties of the polymers were investigated. And the band-gap （Eg）, HOMO orbital energy （EHCMO）, and LUMO orbital energy （EUJMO） of the polymers were calculated. Among the polymers, polymer PBTN and PBTD show lower band-gap （2.67 and 2.63 eV）, lower HOMO energy level （-5.38 and -5.4 eV） and broader wavelength （432 and 438 nm） than that of polymer PBTB （2.69 eV, -5.36 eV and 424 nm） with incorporation of one nitro group or two nitro groups in the main chain, respectively.
文摘A novel polyimide(PI) containing pendent biphenyl ester groups was synthesized from 3,5-diaminobenzoic-4′-biphenyl ester (DABBE)and 3,3′,4,4′-oxydiphthalic dianhydride(ODPA) by a one-step high-temperature polycondensation in m-cresol.This PI is a semicrystalline polymer.Lots of short fine fibric crystals with length and diameter about 20、μm and 1、μm respectively disperse randomly in the PI film. The optical textures and the X-ray diffraction patterns of the PI solution and film show that the PI main chains are in the extended conformation and pack parallel to each other, and the pendent biphenyl ester groups occupy the space between the main chain layers,more or less perpendicular to the main chains.At the same time, mechanical and thermally stable properties of the PI film were investigated. The excellent mechanical properties of general polyimide films are reasonably maintained, the polyimide film with pendent groups showes higher tensile strength and modulus and lower T g. TGA study showes a typical two-step weight loss behavior corresponding to the pyrolysis of pendent groups and main chains of the PI,respectively.
基金financially supported by the National Natural Science Foundation of China(Nos.51403039 and 21476072)the Natural Science Foundation of Shanghai(No.13ZR1451300)
文摘Biphenyl-contained monomer of 1,4-bis[2-（3,4-epoxy cyclohexyl ethyl） dimethylsilyl] biphenyl （BP-SiH-EP） was prepared via hydrosilylation reaction of 1,4-bis（dimethylsilyl） biphenyl （BP-SiH） and 1,2-epoxy-4-vinylcyclohexane in the presence of Karstedt＇s catalyst. ^1H-NMR, 13C-NMR and FTIR were used to characterize the structure of the obtained monomer. BP-SiH-EP was then cured by methyl hexahydrophthalic anhydride （MeHHPA） with 1-cyanoethyl-2-ethyl-4- methylimidazole as an accelerator. The polymerization behavior was studied by DSC. The results of DMA measurement demonstrate that the cured BP-SiH-EP/MeHHPA can maintain high storage modulus （〉1 GPa） in a wide range of temperature up to 176 ℃. According to the damping factor curve of DMA, cured BP-SiH-EP/MeHHPA exhibits a high glass transition temperature （Tg） of 192 ℃, which is 20 ℃ higher than that of cured 1,4-bis[2-（3,4-epoxy cyclohexyl ethyl） dimethylsilyl] benzene （DEDSB）/MeHHPA. TGA results show that cured BP-SiH-EP/MeHHPA has good thermal stability （Tso/o = 339 ℃） due to the high heat-resistance of rigid biphenyl group. Moreover, the crosslinking density of cured BP-SiH-EP/MeHHPA should be lower than that of cured DEDSB/MeHHPA estimated from their chemical structures, which conflicts with the calculated results based on the rubber elasticity equation. The inconsistence indicates that the calculated crosslinking densities are not comparable, possibly owing to their differences in the rigidity of polymer chains and intermolecular interaction.
