Based on the concepts of fast polarization, effective electric field and electron impact ionization criterion, the effect of polymer type on electric breakdown strength （EBD） on a nanosecond time scale is investigat...Based on the concepts of fast polarization, effective electric field and electron impact ionization criterion, the effect of polymer type on electric breakdown strength （EBD） on a nanosecond time scale is investigated, and a formula that qualitatively characterizes the relation between the electric breakdown strength and the polymer type is derived. According to this formula, it is found that the electric breakdown strength decreases with an increase in the effective relative dielectric constants of the polymers. By calculating the effective relative dielectric constants for different types of polymers, the theoretical relation for the electric breakdown strengths of common polymers is predicted. To verify the prediction, the polymers of PE （polyethylene）, PTFE （polytetrafluoroethelene）, PMMA （organic glass） and Nylon are tested with a nanosecond-pulse generator. The experimental result shows EBD （PTFE） 〉 EBD （PMMA） 〉 EBD （Nylon） 〉 EBD （PE）. This result is consistent with the theoretical prediction.展开更多
The development of n-type polymer thermoelectrics lags far behind that of p-type ones in view of material diversity and performance.New structural insights into the thermoelectric performance are needed for efficient ...The development of n-type polymer thermoelectrics lags far behind that of p-type ones in view of material diversity and performance.New structural insights into the thermoelectric performance are needed for efficient n-type polymer thermoelectric materials.Herein,we developed three acceptor-acceptor type organoboron polymers and investigated the effect of backbone configuration on thermoelectric performance.The three polymers are designed based on double B←N bridged bipyridine(BNBP)unit with monomeric thieno[3,4-c]pyrrole-4,6-dione(TPD),TPD dimer and TPD trimer as the copolymerizing units,respectively.The three polymers show similar low LUMO energy levels but different backbone configuration.Compared with the wavy backbone configuration,the pseudo-straight backbone configuration imparts the polymer with much enhanced crystallinity and electron mobility.As a result,after n-doping,the polymer with pseudo-straight configuration shows much higher electronic conductivity and power factor.We think these findings could serve as important guidelines for molecular design toward efficient n-type polymer thermoelectric materials.展开更多
The development of donor-acceptor(D-A)type conjugated polymers depends largely on the design of novel A building blocks.Herein,we report a novel A building block based on the cyano-substituted organoboron unit(SBN-3)....The development of donor-acceptor(D-A)type conjugated polymers depends largely on the design of novel A building blocks.Herein,we report a novel A building block based on the cyano-substituted organoboron unit(SBN-3).Compared with the most common fluorine-substituted B←N unit,SBN-3 displays a significantly downshifted LUMO energy level because of the strong electron-withdrawing ability of cyano groups.In addition,due to the greater impact of cyano substitution on LUMO than on HOMO,SBN-3 exhibits a reduced band gap,nearinfrared absorption and fluorescence properties.The D-A type conjugated polymers based on the cyano-substituted B←N unit with thiophene-based units show narrow optical band gaps of ca.1.3 e V as well as distinctive electronic structures,i.e.,delocalized LUMOs and localized HOMOs.This work thus provides not only an effective approach to design strong A units but also a new electron-deficient building block for D-A type conjugated polymers.展开更多
Amino-type adsorbents(ATAs) were prepared by radiation-induced graft copolymerization of 4-hydroxybutyl acry late glycidyl ether(HB) onto a polyethylene-coated polypropylene(PE/PP) duplex fiber of a non-woven fabric,a...Amino-type adsorbents(ATAs) were prepared by radiation-induced graft copolymerization of 4-hydroxybutyl acry late glycidyl ether(HB) onto a polyethylene-coated polypropylene(PE/PP) duplex fiber of a non-woven fabric,and modified with different amines of ethylenediamine(EDA),diethylenetriamine(DETA),triethylenetetramine(TETA) and diethylamine(DEA).The adsorption behavior of uranyl ions onto the ATAs was studied in batch experiments.The effects of the contact time,initial concentration of the ions,temperature,and pH value.The salinity were investigated along with the adsorption kinetics and the adsorption isotherms.The kinetic experimental data followed the pseudo second-order kinetic model,and the adsorption isotherms correlated well with the Langmuir model.The ATAs showed good efficiency in adsorbing uranyl ions,with the best saturation adsorption capacity being 64.26 mg g^(-1) for ATA-DETA within 120 min.The temperature dependence of ATADETA was quite abnormal and the quickest behavior was obtained at 25 ℃.ATAs showed good adsorption capacity over a wide pH range of 4.0-8.5,and HCl could be used in the elution process.Salinity of the solution had great effect on the adsorption capacity,3.5%salinity resulted in a 55%loss of capacity from ATA-DETA.The selectivity of ATA-DETA showed an order of:UO_2^(2+)≈Fe^(3+)> Zn^(2+) > VO_3^- > Co^(2+) > Ni^(2+).展开更多
A systematic analysis has been carried out to investigate the fields of application and interaction mechanism of polymeric carbohydrate, i.e. polysaccharides (including starch, dextrin, cellulose and cellulosic deriva...A systematic analysis has been carried out to investigate the fields of application and interaction mechanism of polymeric carbohydrate, i.e. polysaccharides (including starch, dextrin, cellulose and cellulosic derivatives) on various oxides and salt-type minerals in the article, interaction mechanisms of electrostatic, of hydrogen bonding, and of chemical interaction between polymeric carbohydrate and these minerals are put forward.展开更多
A series of nickel complexes{4 a:[(2,6-iPr2C6H3)N=CHC16H12O]Ni(Me)(Py),4b:[(2,6-iPr2C6H2OCH3)N=CHC16H12O]-Ni(Me)(Py),4 c:[(2,6-iPr2C6H2Cl)N=CHC16H12O]Ni(Me)(Py),and 4d:[(2,6-iPr2C6H2CF3)N=CHC16H12O]Ni(Me)(Py)}based on...A series of nickel complexes{4 a:[(2,6-iPr2C6H3)N=CHC16H12O]Ni(Me)(Py),4b:[(2,6-iPr2C6H2OCH3)N=CHC16H12O]-Ni(Me)(Py),4 c:[(2,6-iPr2C6H2Cl)N=CHC16H12O]Ni(Me)(Py),and 4d:[(2,6-iPr2C6H2CF3)N=CHC16H12O]Ni(Me)(Py)}based onβ-ketiminato ligands bearing various electron-donating or electron-withdrawing substituents on the para-position of the aniline group were synthesized and unambiguously characterized.The X-ray crystallographic analysis showed that complexes 4 b and 4 d adopted a nearsquare-planar geometry,and the anilines bearing a para-OMe or―CF3 group were found to situate on the axial position of the metal center.All complexes exhibited high activities up to 1.25×10^7–1.35×10^7 g PNB·molNi^–1·h^–1 toward norbornene(NBE)addition polymerization(conversion>91.2%in 2 min)under low loading of B(C6F5)3(B/Ni=3)at 30°C,affording polymers with high molecular weight up to 2.54×10^6–3.18×10^6.Different levels of decrease in catalytic activities could be observed for all catalysts as the reaction temperature increased;4 d bearing a strong electron-withdrawing―CF3 group showed the highest activity at 70°C,while others exhibited notable decrease in catalytic activity with the raise in reaction temperature.Complexes 4 a–4 d showed remarkable tolerance to polar groups and could efficiently promote the copolymerization of NBE with its polar derivatives,including NBE bearing small acetate and hydroxyl group,as well as bulky oligomers,yielding copolymers with high functional NBE incorporations.Novel NBE copolymers with high functional comonomer incorporations and improved solubility were obtained in high yields.展开更多
A couple of novel sulfobetaine copolymer is developed via Michael-type addition reaction. The comonomers, diamines and maleimide react via Michael reaction through UV irradiation using AIBN as photoinitiator producing...A couple of novel sulfobetaine copolymer is developed via Michael-type addition reaction. The comonomers, diamines and maleimide react via Michael reaction through UV irradiation using AIBN as photoinitiator producing polyamine chain. Further, sulfobetaine copolymers were obtained on treatment of the polyamine with sulfopropylating agent, 1,3-propane sultone. These novel sulfobetaine polymers were grafted on silica surface to produce responsive biocompatible surface. This easy straightforward, catalyst free facile protocol for synthesis of polymer grafted surface is useful for developing biomedical devices. Additionally, both the copolymers show fluorescence characteristics.展开更多
Vinyl-type polymerization of norbornene has been carried out with half-titanocene/MAO catalysts. It was found that the Cp（cyclopentadienyl）-bearing titanocene catalysts afford the polynorbornene at much higher yield...Vinyl-type polymerization of norbornene has been carried out with half-titanocene/MAO catalysts. It was found that the Cp（cyclopentadienyl）-bearing titanocene catalysts afford the polynorbornene at much higher yield than the related Cppentamethylcyclopentadienyl-bearing one. On the other hand, substitution of —OR ligand for chlorine at the Cp-bearing compound causes remarkbaly increase in catalytic activity. The optimum temperature for the polymerization is 60 ℃. All the polynorbornenes obtained with CpTi（OCH2Ph）3/MAO catalyst are soluble in the organic solvents such as cyclohexane and monochlorobenzene. The FTIR and 13C NMR spectra indicate that the polynorbornene obtained is vinyl-type polymer and has low stereo-regularity.展开更多
文摘Based on the concepts of fast polarization, effective electric field and electron impact ionization criterion, the effect of polymer type on electric breakdown strength （EBD） on a nanosecond time scale is investigated, and a formula that qualitatively characterizes the relation between the electric breakdown strength and the polymer type is derived. According to this formula, it is found that the electric breakdown strength decreases with an increase in the effective relative dielectric constants of the polymers. By calculating the effective relative dielectric constants for different types of polymers, the theoretical relation for the electric breakdown strengths of common polymers is predicted. To verify the prediction, the polymers of PE （polyethylene）, PTFE （polytetrafluoroethelene）, PMMA （organic glass） and Nylon are tested with a nanosecond-pulse generator. The experimental result shows EBD （PTFE） 〉 EBD （PMMA） 〉 EBD （Nylon） 〉 EBD （PE）. This result is consistent with the theoretical prediction.
基金the National Natural Science Foundation of China(Nos.22075271,21625403,21875244 and 21875241)B.M.thanks the financial supports by State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences and the Jilin Scientific and Technological Development Program(No.20220508142RC).
文摘The development of n-type polymer thermoelectrics lags far behind that of p-type ones in view of material diversity and performance.New structural insights into the thermoelectric performance are needed for efficient n-type polymer thermoelectric materials.Herein,we developed three acceptor-acceptor type organoboron polymers and investigated the effect of backbone configuration on thermoelectric performance.The three polymers are designed based on double B←N bridged bipyridine(BNBP)unit with monomeric thieno[3,4-c]pyrrole-4,6-dione(TPD),TPD dimer and TPD trimer as the copolymerizing units,respectively.The three polymers show similar low LUMO energy levels but different backbone configuration.Compared with the wavy backbone configuration,the pseudo-straight backbone configuration imparts the polymer with much enhanced crystallinity and electron mobility.As a result,after n-doping,the polymer with pseudo-straight configuration shows much higher electronic conductivity and power factor.We think these findings could serve as important guidelines for molecular design toward efficient n-type polymer thermoelectric materials.
基金financially supported by the National Natural Science Foundation of China(Nos.22135007,21875244 and 52073281)Jilin Scientific and Technological Development Program(No.YDZJ202101ZYTS138)。
文摘The development of donor-acceptor(D-A)type conjugated polymers depends largely on the design of novel A building blocks.Herein,we report a novel A building block based on the cyano-substituted organoboron unit(SBN-3).Compared with the most common fluorine-substituted B←N unit,SBN-3 displays a significantly downshifted LUMO energy level because of the strong electron-withdrawing ability of cyano groups.In addition,due to the greater impact of cyano substitution on LUMO than on HOMO,SBN-3 exhibits a reduced band gap,nearinfrared absorption and fluorescence properties.The D-A type conjugated polymers based on the cyano-substituted B←N unit with thiophene-based units show narrow optical band gaps of ca.1.3 e V as well as distinctive electronic structures,i.e.,delocalized LUMOs and localized HOMOs.This work thus provides not only an effective approach to design strong A units but also a new electron-deficient building block for D-A type conjugated polymers.
基金Supported by National Natural Science Foundation of China(Nos.11175234 and 11105210)the"Strategic Priority Research Program"of the Chinese Academy of Sciences(No.XDA02030200)+1 种基金the"Knowledge Innovation Program"of the Chinese Academy of Sciences(No.KJCX2YW-N49)Shanghai Municipal Commission for Science and Technology(Nos.11ZR1445400 and 12ZR1453300)
文摘Amino-type adsorbents(ATAs) were prepared by radiation-induced graft copolymerization of 4-hydroxybutyl acry late glycidyl ether(HB) onto a polyethylene-coated polypropylene(PE/PP) duplex fiber of a non-woven fabric,and modified with different amines of ethylenediamine(EDA),diethylenetriamine(DETA),triethylenetetramine(TETA) and diethylamine(DEA).The adsorption behavior of uranyl ions onto the ATAs was studied in batch experiments.The effects of the contact time,initial concentration of the ions,temperature,and pH value.The salinity were investigated along with the adsorption kinetics and the adsorption isotherms.The kinetic experimental data followed the pseudo second-order kinetic model,and the adsorption isotherms correlated well with the Langmuir model.The ATAs showed good efficiency in adsorbing uranyl ions,with the best saturation adsorption capacity being 64.26 mg g^(-1) for ATA-DETA within 120 min.The temperature dependence of ATADETA was quite abnormal and the quickest behavior was obtained at 25 ℃.ATAs showed good adsorption capacity over a wide pH range of 4.0-8.5,and HCl could be used in the elution process.Salinity of the solution had great effect on the adsorption capacity,3.5%salinity resulted in a 55%loss of capacity from ATA-DETA.The selectivity of ATA-DETA showed an order of:UO_2^(2+)≈Fe^(3+)> Zn^(2+) > VO_3^- > Co^(2+) > Ni^(2+).
文摘A systematic analysis has been carried out to investigate the fields of application and interaction mechanism of polymeric carbohydrate, i.e. polysaccharides (including starch, dextrin, cellulose and cellulosic derivatives) on various oxides and salt-type minerals in the article, interaction mechanisms of electrostatic, of hydrogen bonding, and of chemical interaction between polymeric carbohydrate and these minerals are put forward.
基金financially supported by the National Natural Science Foundation of China (Nos. 21574097 and 21690071)
文摘A series of nickel complexes{4 a:[(2,6-iPr2C6H3)N=CHC16H12O]Ni(Me)(Py),4b:[(2,6-iPr2C6H2OCH3)N=CHC16H12O]-Ni(Me)(Py),4 c:[(2,6-iPr2C6H2Cl)N=CHC16H12O]Ni(Me)(Py),and 4d:[(2,6-iPr2C6H2CF3)N=CHC16H12O]Ni(Me)(Py)}based onβ-ketiminato ligands bearing various electron-donating or electron-withdrawing substituents on the para-position of the aniline group were synthesized and unambiguously characterized.The X-ray crystallographic analysis showed that complexes 4 b and 4 d adopted a nearsquare-planar geometry,and the anilines bearing a para-OMe or―CF3 group were found to situate on the axial position of the metal center.All complexes exhibited high activities up to 1.25×10^7–1.35×10^7 g PNB·molNi^–1·h^–1 toward norbornene(NBE)addition polymerization(conversion>91.2%in 2 min)under low loading of B(C6F5)3(B/Ni=3)at 30°C,affording polymers with high molecular weight up to 2.54×10^6–3.18×10^6.Different levels of decrease in catalytic activities could be observed for all catalysts as the reaction temperature increased;4 d bearing a strong electron-withdrawing―CF3 group showed the highest activity at 70°C,while others exhibited notable decrease in catalytic activity with the raise in reaction temperature.Complexes 4 a–4 d showed remarkable tolerance to polar groups and could efficiently promote the copolymerization of NBE with its polar derivatives,including NBE bearing small acetate and hydroxyl group,as well as bulky oligomers,yielding copolymers with high functional NBE incorporations.Novel NBE copolymers with high functional comonomer incorporations and improved solubility were obtained in high yields.
文摘A couple of novel sulfobetaine copolymer is developed via Michael-type addition reaction. The comonomers, diamines and maleimide react via Michael reaction through UV irradiation using AIBN as photoinitiator producing polyamine chain. Further, sulfobetaine copolymers were obtained on treatment of the polyamine with sulfopropylating agent, 1,3-propane sultone. These novel sulfobetaine polymers were grafted on silica surface to produce responsive biocompatible surface. This easy straightforward, catalyst free facile protocol for synthesis of polymer grafted surface is useful for developing biomedical devices. Additionally, both the copolymers show fluorescence characteristics.
文摘Vinyl-type polymerization of norbornene has been carried out with half-titanocene/MAO catalysts. It was found that the Cp（cyclopentadienyl）-bearing titanocene catalysts afford the polynorbornene at much higher yield than the related Cppentamethylcyclopentadienyl-bearing one. On the other hand, substitution of —OR ligand for chlorine at the Cp-bearing compound causes remarkbaly increase in catalytic activity. The optimum temperature for the polymerization is 60 ℃. All the polynorbornenes obtained with CpTi（OCH2Ph）3/MAO catalyst are soluble in the organic solvents such as cyclohexane and monochlorobenzene. The FTIR and 13C NMR spectra indicate that the polynorbornene obtained is vinyl-type polymer and has low stereo-regularity.
