A new monomer,vinyltriallylsilane(CB3),having functionnal groups with different hydrosilylation reactivity was designed and synthesized by allylation reaction from vinyltrichlorosilane.Then,photocrosslinkable hyperb...A new monomer,vinyltriallylsilane(CB3),having functionnal groups with different hydrosilylation reactivity was designed and synthesized by allylation reaction from vinyltrichlorosilane.Then,photocrosslinkable hyperbranched(poly(siloxysilane)) with terminal allyl groups was prepared via hydrosilylation reaction of vinyltriallylsilane(CB3) and dimethylbis(dimethylsiloxy)silane(A2) monomers at the presence of Karstedt catalyst,and characterized by means of FTIR,()1H-NMR,()29Si-NMR,and SEC/RI/MALLS technology.The polymerization process of A2 and CB3 monomers was studied in situ by using FTIR.It was found that silicon hydride would preferentially react with vinyl groups during the reaction. This can cause to the generation of an intermediate with one Si—H and three allyl groups.By using it to conduct further self-polymerization,hyperbranched polymer can be obtained.The degree of branching of the resulting hyperbranched poly(siloxysilane) was calculated to be 0.44 by quantitative()29Si-NMR spectroscopy,and the weight average molecular weight was 12.1 kg/mol with its polydispersity of 2.52.Finally,the UV curing behavior of the resulting polymer initiated with different photoinitors was also investigated.展开更多
Three hyperbranched poly(siloxysilanes) were prepared from AB3-type monomers at the presence of Karstedt catalyst.The detailed synthesis procedures of AB3-type monomers by reaction between γ-methacryloyloxy propylt...Three hyperbranched poly(siloxysilanes) were prepared from AB3-type monomers at the presence of Karstedt catalyst.The detailed synthesis procedures of AB3-type monomers by reaction between γ-methacryloyloxy propyltrimethoxysilane or vinyltrimethoxysilane with chlorosilane using anhydrous ferric chloride as the catalyst were described.This new approach can simplify the synthetic routes for hyperbranched polysiloxanes.FTIR,()1H-NMR,(()13C-NMR,)()29Si-NMR,elemental analysis and SEC/MALLS were employed to identify the structure of the polymers. The analyses revealed that the reaction between alkoxysilane and chlorosilane could be feasibly catalyzed by anhydrous ferric chloride.The reaction of vinyltrimethoxysilane with chlorosilane could be carried out more easily than that of γ-methylacrylacyloxypropyltrimethoxylsilane with chlorosilane due to its steric hindrance effect.展开更多
以γ-甲基丙烯酰氧丙基三(三甲基硅氧基)硅烷(TRIS)为原料、十八烷基聚醚丙烯酸酯三甲基氯化铵和烷基酚聚氧乙烯基醚为复合乳化体系、2,2'-偶氮二异丁基脒二盐酸盐为引发剂,采用预乳化乳液聚合反应,制备了阳离子型聚甲基丙烯酰氧丙...以γ-甲基丙烯酰氧丙基三(三甲基硅氧基)硅烷(TRIS)为原料、十八烷基聚醚丙烯酸酯三甲基氯化铵和烷基酚聚氧乙烯基醚为复合乳化体系、2,2'-偶氮二异丁基脒二盐酸盐为引发剂,采用预乳化乳液聚合反应,制备了阳离子型聚甲基丙烯酰氧丙基三(三甲基硅氧基)硅烷(PTRIS)乳液。探讨了预乳化方法对单体预乳化液粒径和稳定性的影响;采用正交实验考察了引发剂用量、乳化剂用量、反应温度、反应时间对乳液性能的影响;采用红外光谱对聚合物结构进行表征,并研究其表面性能。结果表明,采用机械搅拌辅助超声均质的方法能获得粒径为229.4 nm、放置30天不分层的单体预乳化液;其乳液聚合反应的最佳条件为:引发剂用量为单体质量的0.75%、乳化剂用量为单体质量的3%、反应温度为75℃、反应时间为4 h,在此条件下制得的PTRIS乳液外观均匀、单体转化率达到94.8%、无凝胶生成、平均粒径357.5 nm、多分散系数0.145、Zeta电位20.2 m V、稳定性良好;经阳离子型PTRIS乳液整理的棉布对水的接触角达135°,对二碘甲烷的接触角达117°,表面能为3.82 m N/m,具有优异的疏水疏油性能。展开更多
Polydimethylsiloxane (PDMS), tetraethoxysilane (TEOS), ethyl alcohol (EtOH) and deionized water were main raw materials to prepare silicone-modified hybrid thin films using sol-gel method. The effect of the cont...Polydimethylsiloxane (PDMS), tetraethoxysilane (TEOS), ethyl alcohol (EtOH) and deionized water were main raw materials to prepare silicone-modified hybrid thin films using sol-gel method. The effect of the contents of H2O and PDMS on thin films was studied. When the volume ratio of H20 to TEOS is 0.5, the optimum quality of thin films is obtained. And the gelation time is affected slightly by H20 content. Uniform thin films are obtained when the volume ratio of PDMS to TEOS is 0.2. Yet, the sol would be inactive in 6 d. Various properties of thin films were studied, including hardness, adhesive quality, hydrophobic property, corrosion protection property, and abrasion resistance. Test results show that the pencil hardness is generally 3-6 H, and adhesive quality achieves the highest standard of 0. When the sintering temperature is below 400℃, the contact angle is about 95° and hydrophobic films are obtained. The abrasion resistance of thin films is better than that of aluminum alloy when the sintering temperature is higher than 300℃. And the excellent corrosion protective effect is obtained by single-layer coating when the sintering temperature is higher than 400℃.展开更多
A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative ...A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative of methyl oleate.Trimethylsilylation reaction was introduced to further improve methyl oleate oxidation stability and lubricity after epoxidation and open-ring reactions.The order of effectiveness of acid binding agent was N,N-diisopropylethylamine(DIEA) > pyridine > diethylamine > triethylamine,and the effects of various parameters on the trimethylsilylation reaction as well as on the silicon-oxygen bond stability and reaction yield were studied.A maximum yield of 34.54%was achieved at hydroxyl/trimethyl chlorosilane/DIEA molar ratio of1:1.25:1,reaction temperature 40℃,reaction time 1.5 h.展开更多
The sorption behavior of acid dyes onto cetyltrimethylammonium bromide (CTAB)- modified silica as a function of pH in the aqueous medium was studied. Single- and multi-solute sorption equilibria of orange II(OR), phen...The sorption behavior of acid dyes onto cetyltrimethylammonium bromide (CTAB)- modified silica as a function of pH in the aqueous medium was studied. Single- and multi-solute sorption equilibria of orange II(OR), phenol red (PR) and Eriochrome Black T (EBT) were studied at pH 3, unbuffered water pH and pH 11. Sorption behavior of EBT could not be conducted at pH 3 due to its aggregation in acidic medium. All the reaction conditions, experimental protocols and techniques remained the same throughout the sorption process. Sorption isotherms for single-solute system were fitted by the Langmuir model, while Langmuir competitive model (LCM) and the ideal adsorbed solution theory (IAST) coupled with Langmuir model (IAST/Langmuir) were used for the prediction of multisolute competitive sorption. Sorption affinities influenced by the factors like physical interactive forces between the molecules of CTA on silica and sorbate, structural limitations of the dyes based on their geometrical arrangement were investigated. Sorption affinity of OR was found to be higher than that of EBT and PR at all the pH values investigated. Magnitude of the sorption capacities was observed to be higher in acidic medium but lower in alkaline medium. Trends of the sorption affinities in multisolute system were similar to those in single-solute system but magnitude of the sorption capacities was significantly reduced due to the prevailing competition among the sorbates.展开更多
Introduced a method of synthesizing hierarchical EU-1 zeolite with organosilanes as additive, and studied the influences of following different kinds of organosilanes on the synthesis of hierarchical EU-1 zeolite: γ-...Introduced a method of synthesizing hierarchical EU-1 zeolite with organosilanes as additive, and studied the influences of following different kinds of organosilanes on the synthesis of hierarchical EU-1 zeolite: γ-glycidoxy propyl trimethoxy silane(GPTMS), N-β-(aminoethyl)-γ-aminopropyl methyl dimethoxyl silane(APAEDMS),and N-(β-aminoethyl)-γ-aminopropyl dimethoxyl(ethyoxyl) silane(TMPED). The hierarchical EU-1 samples were characterized by XRD, SEM, N_2 adsorption, FT-IR and NH_3-TPD to analyze the crystallinity, morphology, surface area, pore size distribution and acidity. The results showed that hierarchical EU-1 zeolites were successfully synthesized; organosilanes have great influence on crystal morphology of EU-1 zeolites; the exterior surface area of hierarchical EU-1 zeolite, which synthesized with organosilanes(APAEDMS) adding into synthesis system, increased by 62.1% and mesopore volume increased by 129.1% compared with conventional EU-1 zeolites, thus can reduce the diffusional restriction markedly in catalytic reaction. The catalytic performance of hierarchical EU-1zeolites were evaluated in m-xylene isomerization on fixed bed reactor. The catalytic data showed that the isomerization activity PX/X of the hierarchical EU-1 zeolites reached around 24.09% in theoretical thermodynamic equilibrium from 23.83%, and the selectivity of C_8 aromatic hydrocarbon increased from 75.16% to 84.87%. The conversion of p-xylene increased from 16.30% to 18.41%.展开更多
This study is to analyze the influence of the modifier, 5~25 wt % titanium tetrabutoxide (TBO), on the hardness and elastic modulus of the films based on SSO deriving from hydrolytic condensation of (3-glycidoxypropy...This study is to analyze the influence of the modifier, 5~25 wt % titanium tetrabutoxide (TBO), on the hardness and elastic modulus of the films based on SSO deriving from hydrolytic condensation of (3-glycidoxypropyl)trimethoxysilane (GPMS) and vinyltrimethoxysilane (VMS), by the continuous stiffness measurement (CSM) technique of an instrumented-indentation testing (IIT) device. Films were synthesized by adding the stoichiometric amount of ethylenediamine (EDA) and benzoyl proxide (BPO) to SSO solutions in ethanol, dip-coating over glass substrates, and curing using an appropriate thermal cycle. Intrinsic values of hardness and elastic modulus were determined with the average values in “plateau region” from “four-layer” explanation. And the brittle index of the modified coating systems was analyzed.展开更多
Mesoporous silica materials with uniform channels containing functionalized organic monolayers have been synthesized by grafting a thiol functional group, (3-Mercaptopropyl) trimethoxysilane (MPTMS). A new approac...Mesoporous silica materials with uniform channels containing functionalized organic monolayers have been synthesized by grafting a thiol functional group, (3-Mercaptopropyl) trimethoxysilane (MPTMS). A new approach to heavy metal ion adsorbents based on the covalent grafting of MPTMS groups to the framework pore walls of mesoporous silica molecular sieves has been developed and investigated with regard to hydroxyl group densities, channel dimensions, morphologies and reaction conditions. Results show that the ordered mesostructures of functionalized samples were retained after modification and the thiol functional group was immobilized mainly inside the mesopore channel. The relative surface coverage of the monolayer can be systematically varied up to 95%. The functionalized hybrid materials show exceptional selectivity and capacity for removing mercury from aqueous waste stream with distribution coefficients up to 435,000. The regenerated material show high mercury ion uptake capacity of 2.87 mmol/g (86.5%).展开更多
文摘A new monomer,vinyltriallylsilane(CB3),having functionnal groups with different hydrosilylation reactivity was designed and synthesized by allylation reaction from vinyltrichlorosilane.Then,photocrosslinkable hyperbranched(poly(siloxysilane)) with terminal allyl groups was prepared via hydrosilylation reaction of vinyltriallylsilane(CB3) and dimethylbis(dimethylsiloxy)silane(A2) monomers at the presence of Karstedt catalyst,and characterized by means of FTIR,()1H-NMR,()29Si-NMR,and SEC/RI/MALLS technology.The polymerization process of A2 and CB3 monomers was studied in situ by using FTIR.It was found that silicon hydride would preferentially react with vinyl groups during the reaction. This can cause to the generation of an intermediate with one Si—H and three allyl groups.By using it to conduct further self-polymerization,hyperbranched polymer can be obtained.The degree of branching of the resulting hyperbranched poly(siloxysilane) was calculated to be 0.44 by quantitative()29Si-NMR spectroscopy,and the weight average molecular weight was 12.1 kg/mol with its polydispersity of 2.52.Finally,the UV curing behavior of the resulting polymer initiated with different photoinitors was also investigated.
文摘Three hyperbranched poly(siloxysilanes) were prepared from AB3-type monomers at the presence of Karstedt catalyst.The detailed synthesis procedures of AB3-type monomers by reaction between γ-methacryloyloxy propyltrimethoxysilane or vinyltrimethoxysilane with chlorosilane using anhydrous ferric chloride as the catalyst were described.This new approach can simplify the synthetic routes for hyperbranched polysiloxanes.FTIR,()1H-NMR,(()13C-NMR,)()29Si-NMR,elemental analysis and SEC/MALLS were employed to identify the structure of the polymers. The analyses revealed that the reaction between alkoxysilane and chlorosilane could be feasibly catalyzed by anhydrous ferric chloride.The reaction of vinyltrimethoxysilane with chlorosilane could be carried out more easily than that of γ-methylacrylacyloxypropyltrimethoxylsilane with chlorosilane due to its steric hindrance effect.
文摘以γ-甲基丙烯酰氧丙基三(三甲基硅氧基)硅烷(TRIS)为原料、十八烷基聚醚丙烯酸酯三甲基氯化铵和烷基酚聚氧乙烯基醚为复合乳化体系、2,2'-偶氮二异丁基脒二盐酸盐为引发剂,采用预乳化乳液聚合反应,制备了阳离子型聚甲基丙烯酰氧丙基三(三甲基硅氧基)硅烷(PTRIS)乳液。探讨了预乳化方法对单体预乳化液粒径和稳定性的影响;采用正交实验考察了引发剂用量、乳化剂用量、反应温度、反应时间对乳液性能的影响;采用红外光谱对聚合物结构进行表征,并研究其表面性能。结果表明,采用机械搅拌辅助超声均质的方法能获得粒径为229.4 nm、放置30天不分层的单体预乳化液;其乳液聚合反应的最佳条件为:引发剂用量为单体质量的0.75%、乳化剂用量为单体质量的3%、反应温度为75℃、反应时间为4 h,在此条件下制得的PTRIS乳液外观均匀、单体转化率达到94.8%、无凝胶生成、平均粒径357.5 nm、多分散系数0.145、Zeta电位20.2 m V、稳定性良好;经阳离子型PTRIS乳液整理的棉布对水的接触角达135°,对二碘甲烷的接触角达117°,表面能为3.82 m N/m,具有优异的疏水疏油性能。
基金supported partly by the School of Mechanical,Electronic and Control Engineering,Beijing Jiaotong university,China
文摘Polydimethylsiloxane (PDMS), tetraethoxysilane (TEOS), ethyl alcohol (EtOH) and deionized water were main raw materials to prepare silicone-modified hybrid thin films using sol-gel method. The effect of the contents of H2O and PDMS on thin films was studied. When the volume ratio of H20 to TEOS is 0.5, the optimum quality of thin films is obtained. And the gelation time is affected slightly by H20 content. Uniform thin films are obtained when the volume ratio of PDMS to TEOS is 0.2. Yet, the sol would be inactive in 6 d. Various properties of thin films were studied, including hardness, adhesive quality, hydrophobic property, corrosion protection property, and abrasion resistance. Test results show that the pencil hardness is generally 3-6 H, and adhesive quality achieves the highest standard of 0. When the sintering temperature is below 400℃, the contact angle is about 95° and hydrophobic films are obtained. The abrasion resistance of thin films is better than that of aluminum alloy when the sintering temperature is higher than 300℃. And the excellent corrosion protective effect is obtained by single-layer coating when the sintering temperature is higher than 400℃.
基金Supported by the National Natural Science Foundation of China(21306088)National Key Technologies R&D Program of China(2015BAD15B07)+1 种基金State Key Laboratory of Chemical Engineering(SKL-Ch E-13A01,Tsinghua University,China)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,China)
文摘A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative of methyl oleate.Trimethylsilylation reaction was introduced to further improve methyl oleate oxidation stability and lubricity after epoxidation and open-ring reactions.The order of effectiveness of acid binding agent was N,N-diisopropylethylamine(DIEA) > pyridine > diethylamine > triethylamine,and the effects of various parameters on the trimethylsilylation reaction as well as on the silicon-oxygen bond stability and reaction yield were studied.A maximum yield of 34.54%was achieved at hydroxyl/trimethyl chlorosilane/DIEA molar ratio of1:1.25:1,reaction temperature 40℃,reaction time 1.5 h.
文摘The sorption behavior of acid dyes onto cetyltrimethylammonium bromide (CTAB)- modified silica as a function of pH in the aqueous medium was studied. Single- and multi-solute sorption equilibria of orange II(OR), phenol red (PR) and Eriochrome Black T (EBT) were studied at pH 3, unbuffered water pH and pH 11. Sorption behavior of EBT could not be conducted at pH 3 due to its aggregation in acidic medium. All the reaction conditions, experimental protocols and techniques remained the same throughout the sorption process. Sorption isotherms for single-solute system were fitted by the Langmuir model, while Langmuir competitive model (LCM) and the ideal adsorbed solution theory (IAST) coupled with Langmuir model (IAST/Langmuir) were used for the prediction of multisolute competitive sorption. Sorption affinities influenced by the factors like physical interactive forces between the molecules of CTA on silica and sorbate, structural limitations of the dyes based on their geometrical arrangement were investigated. Sorption affinity of OR was found to be higher than that of EBT and PR at all the pH values investigated. Magnitude of the sorption capacities was observed to be higher in acidic medium but lower in alkaline medium. Trends of the sorption affinities in multisolute system were similar to those in single-solute system but magnitude of the sorption capacities was significantly reduced due to the prevailing competition among the sorbates.
基金Supported by the National Innovation Fund for Small and Medium-sized Technology-based Firms(14C26211400552)
文摘Introduced a method of synthesizing hierarchical EU-1 zeolite with organosilanes as additive, and studied the influences of following different kinds of organosilanes on the synthesis of hierarchical EU-1 zeolite: γ-glycidoxy propyl trimethoxy silane(GPTMS), N-β-(aminoethyl)-γ-aminopropyl methyl dimethoxyl silane(APAEDMS),and N-(β-aminoethyl)-γ-aminopropyl dimethoxyl(ethyoxyl) silane(TMPED). The hierarchical EU-1 samples were characterized by XRD, SEM, N_2 adsorption, FT-IR and NH_3-TPD to analyze the crystallinity, morphology, surface area, pore size distribution and acidity. The results showed that hierarchical EU-1 zeolites were successfully synthesized; organosilanes have great influence on crystal morphology of EU-1 zeolites; the exterior surface area of hierarchical EU-1 zeolite, which synthesized with organosilanes(APAEDMS) adding into synthesis system, increased by 62.1% and mesopore volume increased by 129.1% compared with conventional EU-1 zeolites, thus can reduce the diffusional restriction markedly in catalytic reaction. The catalytic performance of hierarchical EU-1zeolites were evaluated in m-xylene isomerization on fixed bed reactor. The catalytic data showed that the isomerization activity PX/X of the hierarchical EU-1 zeolites reached around 24.09% in theoretical thermodynamic equilibrium from 23.83%, and the selectivity of C_8 aromatic hydrocarbon increased from 75.16% to 84.87%. The conversion of p-xylene increased from 16.30% to 18.41%.
文摘This study is to analyze the influence of the modifier, 5~25 wt % titanium tetrabutoxide (TBO), on the hardness and elastic modulus of the films based on SSO deriving from hydrolytic condensation of (3-glycidoxypropyl)trimethoxysilane (GPMS) and vinyltrimethoxysilane (VMS), by the continuous stiffness measurement (CSM) technique of an instrumented-indentation testing (IIT) device. Films were synthesized by adding the stoichiometric amount of ethylenediamine (EDA) and benzoyl proxide (BPO) to SSO solutions in ethanol, dip-coating over glass substrates, and curing using an appropriate thermal cycle. Intrinsic values of hardness and elastic modulus were determined with the average values in “plateau region” from “four-layer” explanation. And the brittle index of the modified coating systems was analyzed.
文摘Mesoporous silica materials with uniform channels containing functionalized organic monolayers have been synthesized by grafting a thiol functional group, (3-Mercaptopropyl) trimethoxysilane (MPTMS). A new approach to heavy metal ion adsorbents based on the covalent grafting of MPTMS groups to the framework pore walls of mesoporous silica molecular sieves has been developed and investigated with regard to hydroxyl group densities, channel dimensions, morphologies and reaction conditions. Results show that the ordered mesostructures of functionalized samples were retained after modification and the thiol functional group was immobilized mainly inside the mesopore channel. The relative surface coverage of the monolayer can be systematically varied up to 95%. The functionalized hybrid materials show exceptional selectivity and capacity for removing mercury from aqueous waste stream with distribution coefficients up to 435,000. The regenerated material show high mercury ion uptake capacity of 2.87 mmol/g (86.5%).