The flotation of diaspore and three kinds of silicate minerals, including kaolinite, illite and pyrophyllite, using an organosilicon cationic surfactant (TAS101) as collector and starch as depressant was investigated....The flotation of diaspore and three kinds of silicate minerals, including kaolinite, illite and pyrophyllite, using an organosilicon cationic surfactant (TAS101) as collector and starch as depressant was investigated. The results show that both diaspore and aluminosilicate minerals float readily with organosilicon cationic collector TAS101 at pH values of 4 to 10. Starch has a strong depression effect for diaspore in the alkaline pH region but has little influence on the flotation of aluminosilicate minerals. It is possible to separate diaspore from aluminosilicate minerals using the organosilicon cationic collector and starch depressant. Further studies of bauxite ore flotation were also conducted, and the reverse flotation separation process was adopted. The concentrates with the mass ratio of Al2O3 to SiO2 of 9.58 and Al2O3 recovery of 83.34% are obtained from natural bauxite ore with the mass ratio of Al2O3 to SiO2 of 6.1 at pH value of 11 using the organosilicon cationic collector and starch depressant.展开更多
[Objective] The aim was to explore effects of chitosan and organosilicon on tomato resistance against Botrytis cinerea. [Method] With leaf spraying method adopted, four groups were set in the test, including control g...[Objective] The aim was to explore effects of chitosan and organosilicon on tomato resistance against Botrytis cinerea. [Method] With leaf spraying method adopted, four groups were set in the test, including control group, groups treated with Botrytis cinerea, with chitosan and Botrytis cinerea, and with chitosan, organosilicon, and Botrytis cinerea, in order to study on effects of chitosan and organosilicon on antioxidant enzyme activities of tomato. [Result] Antioxidant enzyme activities of tomato seedlings were improved in groups with chitosan, organosilicon, and Botrytis cinerea and with chitosan and Botrytis cinerea compared with the group treated with Botrytis cinerea. On the 6th d, activities of PAL, SOD, POD, PPO and CAT in groups with chitosan and Botrytis cinerea, and with chitosan, organosilicon, and Botrytis cinerea increased by 27.36%, 52.07%, 43.55%, 82.02% and 71.82%, and 18.91%, 30.22%, 57.14%, 38.09% and 53.64%, respectively. [Conclusion] Antioxidant enzyme activities of tomato seedlings could be improved by chitosan and organosilicon.展开更多
Enhancing cavern sealing is crucial for improving the efficiency of compressed air energy storage(CAES)in hard rock formations.This study introduced a novel approach using a nano-grade organosilicon polymer(NOSP)as a ...Enhancing cavern sealing is crucial for improving the efficiency of compressed air energy storage(CAES)in hard rock formations.This study introduced a novel approach using a nano-grade organosilicon polymer(NOSP)as a sealant,coupled with an air seepage evaluation model that incorporates Knudsen diffusion.Moreover,the initial coating application methods were outlined,and the advantages of using NOSP compared to other sealing materials,particularly regarding cost and construction techniques,were also examined and discussed.Experimental results indicated a significant reduction in permeability of rock specimens coated with a 7–10μm thick NOSP layer.Specifically,under a 0.5 MPa pulse pressure,the permeability decreased to less than 1 n D,and under a 4 MPa pulse pressure,it ranged between4.5×10^(-6)–5.5×10^(-6)m D,marking a 75%–80%decrease in granite permeability.The sealing efficacy of NOSP surpasses concrete and is comparable to rubber materials.The optimal viscosity for application lies between 95 and 105 KU,and the coating thickness should ideally range from 7 to 10μm,applied to substrates with less than 3%porosity.This study provides new insights into air transport and sealing mechanisms at the pore level,proposing NOSP as a cost-effective and simplified solution for CAES applications.展开更多
In order to avoid leakage problem caused by liquid electrolyte, a new ionogel electrolyte was developed by in situ immobilizing organosilicon-functionalized ionic liquid within a nanoporous silica matrix. The ionic li...In order to avoid leakage problem caused by liquid electrolyte, a new ionogel electrolyte was developed by in situ immobilizing organosilicon-functionalized ionic liquid within a nanoporous silica matrix. The ionic liquid evenly coats on the surface of porous silica and fills in the silica framework pores with no strong chemical interaction. The ionogel electrolyte has the dual advantages of a silica solid support and a wide electrochemical stability window of ionic liquid （4.87 V vs. Li^＋/Li）. The half-cells assembled with this electrolyte and LiFePO4 electrode have excellent performance at room temperature and 60 ℃. The Li/SiO2-IGE/LiFePO4 cell displays a discharge capacity of 129.1 mAh·g^-1 after 200 charge/discharge cycles at room temperature.展开更多
The deposition of organosilicone thin films from hexamethyldisiloxane（HMDSO） by using a dual-frequency （50 kHz/33 MHz） atmospheric-pressure micro-plasma jet with an admixture of a small volume of HMDSO and Ar was ...The deposition of organosilicone thin films from hexamethyldisiloxane（HMDSO） by using a dual-frequency （50 kHz/33 MHz） atmospheric-pressure micro-plasma jet with an admixture of a small volume of HMDSO and Ar was investigated.The topography was measured by using scanning electron microscopy.The chemical bond and composition of these films were analyzed by Fourier transform infrared spectroscopy （FTIR） and x-ray photoelectron spectroscopy.The results indicated that the as-deposited film was constituted by silicon,carbon,and oxygen elements,and FTIR suggested the films are organosilicon with the organic component （-CHx） and hydroxyl functional group（-OH） connected to the Si-O-Si backbone.Thin-film hardness was recorded by an MH-5-VM Digital Micro-Hardness Tester.Radio frequency power had a strong impact on film hardness and the hardness increased with increasing power.展开更多
Based on determination for surface tension of organosilicone solution and its expansion on the solid surface, the biological activity of 5% emameetin ben- zoate WDG with organosilicone against beet armyworm was determ...Based on determination for surface tension of organosilicone solution and its expansion on the solid surface, the biological activity of 5% emameetin ben- zoate WDG with organosilicone against beet armyworm was determined by spraying method to study their synergistic activity. The results showed that organosilicone significandy reduced surface tension of aqueous solution, and the surface tension was reduced to 26raN/m as the concentration of organosilicone was 0.01%. The organosilicone significantly raised expansion of liquid drops on solid surface, and the expansion diameter of 10 μL 0.01% organosilicone was 34 ram. The indoor toxicity results indicated that when addition dosage of organosilieone was 1% -5%, synergistic activity of 5% emamectin benzoate WDG with organosilicone against beet armyworm was significant, and increase extent of synergistic activity slowed down as organosilieone dosage was higher than 5%. Field experiment showed that the control efficacies of 5% emamectin benzoate WDG ＋5% organosilicone 33 mg/ L against beet armyworm were 81.57% and 82.66% after spraying for 3 and 7 d respectively, which were significandy better than treatments of 5% emamectin benzoate WDG 33 rag/L, 24% metaflumizone SC 96 mg/L, 5% chlorantranilip- role SC 33 mg/L, 20% tlubendiamide WDG 40 mg/L and 15% indoxacarb EC 43 mg/L.展开更多
Organosilicon compounds play an important role in the fields of materials science,pharmacy,and organic synthesis.The development of effective approaches for the preparation of these compounds have also become a resear...Organosilicon compounds play an important role in the fields of materials science,pharmacy,and organic synthesis.The development of effective approaches for the preparation of these compounds have also become a research focus in organic synthesis.In recent years,free radical synthesis of organosilicons has been vigorously developed,which generally has the advantages of milder synthesis conditions,higher yields and selectivity,and free of precious metal catalysts compared with traditional strategies.This article reviews research progresses in the synthesis of organosilico n compounds by free radical pathways since 2016.In most cases,the radical silylation is achieved based on the reaction of silyl radicals,which are triggered by four routes including peroxide,transition-metal-induced peroxide decomposition,alkali,photocatalysis.The alkyl radicals can also initiate the radical silylation for the generation of C(sp^(3))—Si bonds.展开更多
Effects of organosilicon coating with light stabilizer UV326,UV531 and 770 on ultraviolet (UV) aging resistance of bitumen were investigated by testing the viscosity,softening point and the changes of chemical compone...Effects of organosilicon coating with light stabilizer UV326,UV531 and 770 on ultraviolet (UV) aging resistance of bitumen were investigated by testing the viscosity,softening point and the changes of chemical component before and after UV aging. The results show that UV aging resistance of bitumen is improved due to the good weatherability of organosilicon. And the UV aging resistance of bitumen is further enhanced by adding light stabilizer into organosilicon coating due to the good UV absorption of light stabilizers. Bitumen coated with organosilicon coating containing UV326 exhibits better UV aging resistance in comparison with bitumen coated with organosilicon containing UV531 or 770.展开更多
The evolution of electronic communication technology raises higher requirements for low dielectric constant(low-k)materials.For this,a benzoxazine functional organosilicon(HP-aptes)with dense Si—O—Si crosslinking ne...The evolution of electronic communication technology raises higher requirements for low dielectric constant(low-k)materials.For this,a benzoxazine functional organosilicon(HP-aptes)with dense Si—O—Si crosslinking networks and large sterically hindered tert-butyl groups was prepared by the sol–gel method.Then,a series of polybenzoxazine composites(PPHP)were prepared from intrinsically low dielectric constant bis-functional benzoxazine monomer(P-aptmds)and HP-aptes.The double crosslinking networks of polybenzoxazine and organosilicon further increased the crosslinking density and decreased the dipole density of composites,which endowed the composites with enhanced low-k properties.When the content of HP-aptes is 30%(mass),the crosslinking density was 2.05×10^(-3)mol·cm^(-3),while that of PP-aptmds was 3.31×10^(-3)mol·cm^(-3).In addition,the dielectric constant and dielectric loss of PPHP composite at 1 MHz could reach 2.61 and 0.0056,respectively.展开更多
Immobilization of active molecules by attachment onto solid surfaces is a well-established practice in many processes and applications. Silica micro- and nano-particles are attractive candidates as support for active ...Immobilization of active molecules by attachment onto solid surfaces is a well-established practice in many processes and applications. Silica micro- and nano-particles are attractive candidates as support for active molecules as a result of a combination of desirable properties. The present study deals with grafting of a functional UV active molecule onto silica surfaces via hydrosilylation reactions using multivalent organosilicon spacers. Different types of organosilicon precursors based on dimethylsiloxysilanes containing multiple SiH groups were used as spacers between vinyl-modified silica surface and the benzotriazole UV-absorber (UVA). Firstly, the surface of silica was modified with vinyltrimetoxsisilane coupling agent. The UVA molecules were attached to the silica-vinyl by a two-step procedure involving hydrosilylation reaction. The successful grafting was confirmed by FTIR, TGA and UV-Vis characterization. More than fivefold increase in UVA loading was found for the MH30 multifunctional spacer, which contains approximately 75 SiH groups per molecule, when compared to a four-functional spacer. Furthermore a branched, bulky six-functional spacer is preferred over a linear spacer of the same functionality. UV activity of functionalized silica was studied by UV-Vis spectroscopy, indicating that the immobilization of UVA onto silica surface has not altered its UV absorbance properties.展开更多
Occasionally,a synthetic strategy is developed that seems to be a game changer.Not long ago,mechanochemistry or ionic liquids were intensively explored to afford organosilicon compounds.These and other approaches stil...Occasionally,a synthetic strategy is developed that seems to be a game changer.Not long ago,mechanochemistry or ionic liquids were intensively explored to afford organosilicon compounds.These and other approaches still offer benefits and influence the development of this field.Electrochemistry is currently a new synthetic strategy.Despite its long history,electrosynthesis or electrocatalysis have not become routine procedures in the synthesis of organosilicons.One may justifiably ask why.Accessibility and reproducibility are one of the challenges of electrochemical approaches.However,recent developments in the field of electrified organic synthesis have provided new insights and allowed electrochemistry to become an approachable tool.In this perspective article,several notable contributions to the electrochemical synthesis of organosilicon compounds are highlighted.展开更多
Amphiphilic solid nanoparticles can stabilize a biphasic system to form a Pickering emulsion like organic amphiphilic surfactants,and have profound implications for oil-aqueous biphasic reactions.In the current work,f...Amphiphilic solid nanoparticles can stabilize a biphasic system to form a Pickering emulsion like organic amphiphilic surfactants,and have profound implications for oil-aqueous biphasic reactions.In the current work,for the first time,we prepared an amphiphilic organosilicon framework(AOF)simply by hydrolysis and condensation of the amphiphilic organosiloxane precursor 2,5-bis[(E)-2-(triethoxysilyl)vinyl]pyridine[BTOSVP]which can be used as a Pickering emulsifier and a catalyst carrier for a W–O emulsion in various systems.After catalyst TS-1 was implanted in the amphiphilic AOF carrier,it turned into a solid Pickering catalyst,yolk–shell TS-1@AOF,that can stabilize water–oil emulsions and catalyze reactions at the liquid/liquid interface.The obtained Pickering catalyst showed remarkable activity toward the epoxidation reaction of 1-hexene in water with hydrogen peroxide(H_(2)O_(2))as oxidant.展开更多
To enhance the utilization of pesticides and reduce environmental risks,we constructed the magnetic recyclable and dual stimulus-responsive microspheres to achieve on-demand pesticide release.Magnetic multi-shell holl...To enhance the utilization of pesticides and reduce environmental risks,we constructed the magnetic recyclable and dual stimulus-responsive microspheres to achieve on-demand pesticide release.Magnetic multi-shell hollow mesoporous organosilicon nanoparticles(mMSN)were prepared by one-step hydrothermal method and loaded with pesticide avermectin(A@mMSN),afterward A@mMSN was coated with gelatin through emulsification and chemical cross-linking to prepare A@mMSN@G microspheres(21.5±9.7μm).After being absorbed by the pests,the gelatin layer was hydrolyzed with the neutral protease,and the disulfide bonds within mMSN framework were decomposed by glutathione(GSH),endowing A@mMSN@G microspheres with enzyme and GSH responsiveness to achieve sustained avermectin release till 7 days(about 3.5 times that of the commercial avermectin emulsion).Importantly,the A@mMSN@G microspheres containing Fe3O4 nanoparticles could be easily magnetically collected from soil with a recovery ratio of 63.7%,to reduce the environmental risks.With excellent biosafety,A@mMSN@G microspheres showed outstanding pest control effects till two weeks and the growth of cabbage was not affected by it.Therefore,based on the recyclability and dual stimulus-responsive controllable release,the fabricated A@mMSN@G microspheres have broad application potential in pesticide delivery.展开更多
Polymer-derived ceramics(PDCs) strategy shows a great deal of advantages for the fabrication of advanced ceramics. Organosilicon polymers facilitate the shaping process and different silicon-based ceramics with contro...Polymer-derived ceramics(PDCs) strategy shows a great deal of advantages for the fabrication of advanced ceramics. Organosilicon polymers facilitate the shaping process and different silicon-based ceramics with controllable components can be fabricated by modifying organosilicon polymers or adding fillers. It is worth noting that silicate ceramics can also be fabricated from organosilicon polymers by the introduction of active fillers, which could react with the produced silica during pyrolysis. The organosilicon polymer-derived ceramics show many unique properties, which have attracted many attentions in various fields. This review summarizes the typical organosilicon polymers and the processing of organosilicon polymers to fabricate silicon-based ceramics, especially highlights the three-dimensional(3 D) printing technique for shaping the organosilicon polymerderived ceramics, which makes the possibility to fabricate silicon-based ceramics with complex structure. More importantly, the recent studies on fabricating typical non-oxide and silicate ceramics derived from organosilicon polymers and their biomedical applications are highlighted.展开更多
Comprehensive Summary,Low dielectric(low-k)organosilicon polymers have received extensive interests from industry and academia due to good electrical insulation,high temperature resistance,flame retardancy and hydroph...Comprehensive Summary,Low dielectric(low-k)organosilicon polymers have received extensive interests from industry and academia due to good electrical insulation,high temperature resistance,flame retardancy and hydrophobicity.These attractive properties enable them to be utilized as low-k materials in fabrication of electronic devices in high-frequency communication technology.This review summarizes recent progress in developing low-k organosilicon polymers,including the synthetic methods and properties of different organosilicon polymers classified according to the chemical structures.It may provide some inspiration to design new low-k organosilicon polymers for application in the.展开更多
基金Project(51304085)supported by the National Natural Science Foundation of ChinaProject(GJJ12363)supported by the Education Department of Jiangxi Province,ChinaProject(20142BAB216021)supported by the Natural Science Foundation of Jiangxi Province,China
文摘The flotation of diaspore and three kinds of silicate minerals, including kaolinite, illite and pyrophyllite, using an organosilicon cationic surfactant (TAS101) as collector and starch as depressant was investigated. The results show that both diaspore and aluminosilicate minerals float readily with organosilicon cationic collector TAS101 at pH values of 4 to 10. Starch has a strong depression effect for diaspore in the alkaline pH region but has little influence on the flotation of aluminosilicate minerals. It is possible to separate diaspore from aluminosilicate minerals using the organosilicon cationic collector and starch depressant. Further studies of bauxite ore flotation were also conducted, and the reverse flotation separation process was adopted. The concentrates with the mass ratio of Al2O3 to SiO2 of 9.58 and Al2O3 recovery of 83.34% are obtained from natural bauxite ore with the mass ratio of Al2O3 to SiO2 of 6.1 at pH value of 11 using the organosilicon cationic collector and starch depressant.
文摘[Objective] The aim was to explore effects of chitosan and organosilicon on tomato resistance against Botrytis cinerea. [Method] With leaf spraying method adopted, four groups were set in the test, including control group, groups treated with Botrytis cinerea, with chitosan and Botrytis cinerea, and with chitosan, organosilicon, and Botrytis cinerea, in order to study on effects of chitosan and organosilicon on antioxidant enzyme activities of tomato. [Result] Antioxidant enzyme activities of tomato seedlings were improved in groups with chitosan, organosilicon, and Botrytis cinerea and with chitosan and Botrytis cinerea compared with the group treated with Botrytis cinerea. On the 6th d, activities of PAL, SOD, POD, PPO and CAT in groups with chitosan and Botrytis cinerea, and with chitosan, organosilicon, and Botrytis cinerea increased by 27.36%, 52.07%, 43.55%, 82.02% and 71.82%, and 18.91%, 30.22%, 57.14%, 38.09% and 53.64%, respectively. [Conclusion] Antioxidant enzyme activities of tomato seedlings could be improved by chitosan and organosilicon.
基金supported by the National Natural Science Foundation of China(No.42272321)Hubei Provincial Key Research Projects(Nos.2022BAA093 and 2022BAD163)+1 种基金Major Scientific and Technological Special Project of Jiangxi Province(No.2023ACG01004)WSGRI Engineering&Surveying Incorporation Limited(No.6120230256)。
文摘Enhancing cavern sealing is crucial for improving the efficiency of compressed air energy storage(CAES)in hard rock formations.This study introduced a novel approach using a nano-grade organosilicon polymer(NOSP)as a sealant,coupled with an air seepage evaluation model that incorporates Knudsen diffusion.Moreover,the initial coating application methods were outlined,and the advantages of using NOSP compared to other sealing materials,particularly regarding cost and construction techniques,were also examined and discussed.Experimental results indicated a significant reduction in permeability of rock specimens coated with a 7–10μm thick NOSP layer.Specifically,under a 0.5 MPa pulse pressure,the permeability decreased to less than 1 n D,and under a 4 MPa pulse pressure,it ranged between4.5×10^(-6)–5.5×10^(-6)m D,marking a 75%–80%decrease in granite permeability.The sealing efficacy of NOSP surpasses concrete and is comparable to rubber materials.The optimal viscosity for application lies between 95 and 105 KU,and the coating thickness should ideally range from 7 to 10μm,applied to substrates with less than 3%porosity.This study provides new insights into air transport and sealing mechanisms at the pore level,proposing NOSP as a cost-effective and simplified solution for CAES applications.
基金financially supported by the National Key Research and Development Program of China(No.2016YFB0100204)the National Natural Science Foundation of China(No.51772030)+2 种基金the Joint Funds of the National Natural Science Foundation of China(No.U1564206)the Major Achievements Transformation Project for Central University in Beijingthe Science and Technology Project of State Grid Corporation of China(No.15-JS-191)
文摘In order to avoid leakage problem caused by liquid electrolyte, a new ionogel electrolyte was developed by in situ immobilizing organosilicon-functionalized ionic liquid within a nanoporous silica matrix. The ionic liquid evenly coats on the surface of porous silica and fills in the silica framework pores with no strong chemical interaction. The ionogel electrolyte has the dual advantages of a silica solid support and a wide electrochemical stability window of ionic liquid （4.87 V vs. Li^＋/Li）. The half-cells assembled with this electrolyte and LiFePO4 electrode have excellent performance at room temperature and 60 ℃. The Li/SiO2-IGE/LiFePO4 cell displays a discharge capacity of 129.1 mAh·g^-1 after 200 charge/discharge cycles at room temperature.
基金supported by National Natural Science Foundation of China(Grant No.11165012,Grant No. 11665012)the Project of the Natural Science Foundation of GanSu(145RJZA159)
文摘The deposition of organosilicone thin films from hexamethyldisiloxane（HMDSO） by using a dual-frequency （50 kHz/33 MHz） atmospheric-pressure micro-plasma jet with an admixture of a small volume of HMDSO and Ar was investigated.The topography was measured by using scanning electron microscopy.The chemical bond and composition of these films were analyzed by Fourier transform infrared spectroscopy （FTIR） and x-ray photoelectron spectroscopy.The results indicated that the as-deposited film was constituted by silicon,carbon,and oxygen elements,and FTIR suggested the films are organosilicon with the organic component （-CHx） and hydroxyl functional group（-OH） connected to the Si-O-Si backbone.Thin-film hardness was recorded by an MH-5-VM Digital Micro-Hardness Tester.Radio frequency power had a strong impact on film hardness and the hardness increased with increasing power.
文摘Based on determination for surface tension of organosilicone solution and its expansion on the solid surface, the biological activity of 5% emameetin ben- zoate WDG with organosilicone against beet armyworm was determined by spraying method to study their synergistic activity. The results showed that organosilicone significandy reduced surface tension of aqueous solution, and the surface tension was reduced to 26raN/m as the concentration of organosilicone was 0.01%. The organosilicone significantly raised expansion of liquid drops on solid surface, and the expansion diameter of 10 μL 0.01% organosilicone was 34 ram. The indoor toxicity results indicated that when addition dosage of organosilieone was 1% -5%, synergistic activity of 5% emamectin benzoate WDG with organosilicone against beet armyworm was significant, and increase extent of synergistic activity slowed down as organosilieone dosage was higher than 5%. Field experiment showed that the control efficacies of 5% emamectin benzoate WDG ＋5% organosilicone 33 mg/ L against beet armyworm were 81.57% and 82.66% after spraying for 3 and 7 d respectively, which were significandy better than treatments of 5% emamectin benzoate WDG 33 rag/L, 24% metaflumizone SC 96 mg/L, 5% chlorantranilip- role SC 33 mg/L, 20% tlubendiamide WDG 40 mg/L and 15% indoxacarb EC 43 mg/L.
基金the Fundamental Research Funds for the Central Universities(No.30920021120)Key Laboratory of Biomass Energy and Material,Jiangsu Province(No.JSBEM201912)+1 种基金the National Natural Science Foundation of China(No.21905089)the Chinese Postdoctoral Science Foundation(No.2019M662775)for financial support。
文摘Organosilicon compounds play an important role in the fields of materials science,pharmacy,and organic synthesis.The development of effective approaches for the preparation of these compounds have also become a research focus in organic synthesis.In recent years,free radical synthesis of organosilicons has been vigorously developed,which generally has the advantages of milder synthesis conditions,higher yields and selectivity,and free of precious metal catalysts compared with traditional strategies.This article reviews research progresses in the synthesis of organosilico n compounds by free radical pathways since 2016.In most cases,the radical silylation is achieved based on the reaction of silyl radicals,which are triggered by four routes including peroxide,transition-metal-induced peroxide decomposition,alkali,photocatalysis.The alkyl radicals can also initiate the radical silylation for the generation of C(sp^(3))—Si bonds.
基金a research project 51078300 supported by National Natural Science Foundation of chinasupported by self-determined and innovative research funds of WUT(2010-YB-04)
文摘Effects of organosilicon coating with light stabilizer UV326,UV531 and 770 on ultraviolet (UV) aging resistance of bitumen were investigated by testing the viscosity,softening point and the changes of chemical component before and after UV aging. The results show that UV aging resistance of bitumen is improved due to the good weatherability of organosilicon. And the UV aging resistance of bitumen is further enhanced by adding light stabilizer into organosilicon coating due to the good UV absorption of light stabilizers. Bitumen coated with organosilicon coating containing UV326 exhibits better UV aging resistance in comparison with bitumen coated with organosilicon containing UV531 or 770.
基金the Innovation Program of the Shanghai Municipal Education Commission(2019-01-07-00-02-E00061)the Shanghai Municipal Science and Technology Commission(21520761100).
文摘The evolution of electronic communication technology raises higher requirements for low dielectric constant(low-k)materials.For this,a benzoxazine functional organosilicon(HP-aptes)with dense Si—O—Si crosslinking networks and large sterically hindered tert-butyl groups was prepared by the sol–gel method.Then,a series of polybenzoxazine composites(PPHP)were prepared from intrinsically low dielectric constant bis-functional benzoxazine monomer(P-aptmds)and HP-aptes.The double crosslinking networks of polybenzoxazine and organosilicon further increased the crosslinking density and decreased the dipole density of composites,which endowed the composites with enhanced low-k properties.When the content of HP-aptes is 30%(mass),the crosslinking density was 2.05×10^(-3)mol·cm^(-3),while that of PP-aptmds was 3.31×10^(-3)mol·cm^(-3).In addition,the dielectric constant and dielectric loss of PPHP composite at 1 MHz could reach 2.61 and 0.0056,respectively.
文摘Immobilization of active molecules by attachment onto solid surfaces is a well-established practice in many processes and applications. Silica micro- and nano-particles are attractive candidates as support for active molecules as a result of a combination of desirable properties. The present study deals with grafting of a functional UV active molecule onto silica surfaces via hydrosilylation reactions using multivalent organosilicon spacers. Different types of organosilicon precursors based on dimethylsiloxysilanes containing multiple SiH groups were used as spacers between vinyl-modified silica surface and the benzotriazole UV-absorber (UVA). Firstly, the surface of silica was modified with vinyltrimetoxsisilane coupling agent. The UVA molecules were attached to the silica-vinyl by a two-step procedure involving hydrosilylation reaction. The successful grafting was confirmed by FTIR, TGA and UV-Vis characterization. More than fivefold increase in UVA loading was found for the MH30 multifunctional spacer, which contains approximately 75 SiH groups per molecule, when compared to a four-functional spacer. Furthermore a branched, bulky six-functional spacer is preferred over a linear spacer of the same functionality. UV activity of functionalized silica was studied by UV-Vis spectroscopy, indicating that the immobilization of UVA onto silica surface has not altered its UV absorbance properties.
基金supported by a National Science Centre Grant UMO-2021/43/D/ST4/00132.
文摘Occasionally,a synthetic strategy is developed that seems to be a game changer.Not long ago,mechanochemistry or ionic liquids were intensively explored to afford organosilicon compounds.These and other approaches still offer benefits and influence the development of this field.Electrochemistry is currently a new synthetic strategy.Despite its long history,electrosynthesis or electrocatalysis have not become routine procedures in the synthesis of organosilicons.One may justifiably ask why.Accessibility and reproducibility are one of the challenges of electrochemical approaches.However,recent developments in the field of electrified organic synthesis have provided new insights and allowed electrochemistry to become an approachable tool.In this perspective article,several notable contributions to the electrochemical synthesis of organosilicon compounds are highlighted.
基金supported by the National Natural Science Foundation of China(21390394)the National Basic Research Program of China(2012CB821700 and 2011CB808703)+3 种基金NSFC(21261130584 and 91022030)“111”project(B07016)Award Project of KAUST(CRG-1-2012-LAI-009)Ministry of Education,Science and Technology Development Center Project(20120061130012).
文摘Amphiphilic solid nanoparticles can stabilize a biphasic system to form a Pickering emulsion like organic amphiphilic surfactants,and have profound implications for oil-aqueous biphasic reactions.In the current work,for the first time,we prepared an amphiphilic organosilicon framework(AOF)simply by hydrolysis and condensation of the amphiphilic organosiloxane precursor 2,5-bis[(E)-2-(triethoxysilyl)vinyl]pyridine[BTOSVP]which can be used as a Pickering emulsifier and a catalyst carrier for a W–O emulsion in various systems.After catalyst TS-1 was implanted in the amphiphilic AOF carrier,it turned into a solid Pickering catalyst,yolk–shell TS-1@AOF,that can stabilize water–oil emulsions and catalyze reactions at the liquid/liquid interface.The obtained Pickering catalyst showed remarkable activity toward the epoxidation reaction of 1-hexene in water with hydrogen peroxide(H_(2)O_(2))as oxidant.
基金supported by the Guangzhou Science and Technology Program Project(No.202206010187 and 2023B03J1332)the National Natural Science Foundation of China(No.22208115)+1 种基金the Fundamental Research Funds for the Central Universities(No.2023ZYGXZR041)the Young Elite Scientists Sponsorship Program by CAST(No.2022QNRC001).
文摘To enhance the utilization of pesticides and reduce environmental risks,we constructed the magnetic recyclable and dual stimulus-responsive microspheres to achieve on-demand pesticide release.Magnetic multi-shell hollow mesoporous organosilicon nanoparticles(mMSN)were prepared by one-step hydrothermal method and loaded with pesticide avermectin(A@mMSN),afterward A@mMSN was coated with gelatin through emulsification and chemical cross-linking to prepare A@mMSN@G microspheres(21.5±9.7μm).After being absorbed by the pests,the gelatin layer was hydrolyzed with the neutral protease,and the disulfide bonds within mMSN framework were decomposed by glutathione(GSH),endowing A@mMSN@G microspheres with enzyme and GSH responsiveness to achieve sustained avermectin release till 7 days(about 3.5 times that of the commercial avermectin emulsion).Importantly,the A@mMSN@G microspheres containing Fe3O4 nanoparticles could be easily magnetically collected from soil with a recovery ratio of 63.7%,to reduce the environmental risks.With excellent biosafety,A@mMSN@G microspheres showed outstanding pest control effects till two weeks and the growth of cabbage was not affected by it.Therefore,based on the recyclability and dual stimulus-responsive controllable release,the fabricated A@mMSN@G microspheres have broad application potential in pesticide delivery.
基金support by grants from the National Natural Science Foundation of China(Grant No.51872185)the Science and Technology Commission of Shanghai Municipality(Grant No.17060502400)the University of Shanghai for Science and Technology(Grant No.2017KJFZ010).
文摘Polymer-derived ceramics(PDCs) strategy shows a great deal of advantages for the fabrication of advanced ceramics. Organosilicon polymers facilitate the shaping process and different silicon-based ceramics with controllable components can be fabricated by modifying organosilicon polymers or adding fillers. It is worth noting that silicate ceramics can also be fabricated from organosilicon polymers by the introduction of active fillers, which could react with the produced silica during pyrolysis. The organosilicon polymer-derived ceramics show many unique properties, which have attracted many attentions in various fields. This review summarizes the typical organosilicon polymers and the processing of organosilicon polymers to fabricate silicon-based ceramics, especially highlights the three-dimensional(3 D) printing technique for shaping the organosilicon polymerderived ceramics, which makes the possibility to fabricate silicon-based ceramics with complex structure. More importantly, the recent studies on fabricating typical non-oxide and silicate ceramics derived from organosilicon polymers and their biomedical applications are highlighted.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.22175195,22075311 and 21975278).
文摘Comprehensive Summary,Low dielectric(low-k)organosilicon polymers have received extensive interests from industry and academia due to good electrical insulation,high temperature resistance,flame retardancy and hydrophobicity.These attractive properties enable them to be utilized as low-k materials in fabrication of electronic devices in high-frequency communication technology.This review summarizes recent progress in developing low-k organosilicon polymers,including the synthetic methods and properties of different organosilicon polymers classified according to the chemical structures.It may provide some inspiration to design new low-k organosilicon polymers for application in the.
