硅胶固载γ-氯丙基三甲氧基硅烷制备水不溶性杀菌剂中间体

采用硅胶作为水不溶性杀菌剂的载体 ;以γ 氯丙基三甲氧基硅烷作为联接硅胶和杀菌活性官能团的偶联剂 ;在硅胶上键合γ 氯丙基三甲氧基硅烷的最佳反应条件为 :使用二甲苯作反应溶剂 ,80℃反应 6h以上 ,原料硅胶最好要经丙酮处理 ,γ 氯丙基三甲氧基硅烷与硅胶的质量比为 1∶1即可。使用所研制的中间体制备的水不溶性杀菌剂用量 2mg mL时杀菌率达到 98%。     

硅胶固载γ－氯丙基三甲氧基硅烷制备水不溶性杀菌剂中间体

北京石油化工学院的李凤艳等采用硅胶作为水不溶性杀菌剂的载体，以γ－氯丙基三甲氧基硅烷作为连接硅胶和杀菌活性官能团的偶联剂；在硅胶上键合γ－氯丙基三甲氧基硅烷的最佳反应条件为：二甲苯作溶剂，80 ℃反应6 h以上，硅胶最好经丙酮处理，γ－氯丙基三甲氧基硅烷与硅胶的质量比为1∶1。使用该中间体制备的水不溶性杀菌剂2 mg／mL时，杀菌率达到98%。     

γ-叔丁基过氧丙基三甲氧基硅烷的制备及表征

以过氧化氢叔丁醇和3-氯丙基三甲氧基硅烷为原料,以三氯化铁为催化剂在甲苯溶剂中首次了合成γ-叔丁基过氧丙基三甲氧基硅烷。利用红外吸收光谱、¹H核磁共振谱以及质谱对产物表征,确定其结构。通过研究催化剂种类、反应物配比、反应时间以及反应温度等因素对合成反应的影响,探讨出实验最佳方案为:反应时间8h,反应温度40℃,n(过氧化氢叔丁醇):n(3-氯丙基三甲氧基硅烷)=1.2:1,催化剂用量为3-氯丙基三甲氧基硅烷质量的1.5%。在此条件下,产物产率最高为42%。     

原位聚合连续纤维增强聚甲基丙烯酸甲酯复合材料的界面及性能研究

通过选用含不同官能团的硅烷偶联剂3-甲基丙烯酰氧丙基三甲氧基硅烷(MPS)、γ-氨丙基三甲氧基硅烷(APS)和γ-氯丙基三甲氧基硅烷(CPS)处理玻璃纤维,然后通过原位聚合的方法制造了连续纤维增强的聚甲基丙烯酸甲酯(PMMA)复合材料。研究结果表明,经过这三种偶联剂处理的玻璃纤维与基体树脂在界面分别形成了化学键、范德华力和氢键。红外、动态力学分析和扫描电镜研究表明,复合材料的界面粘接强度顺序为:MPS>CPS>APS。MPS处理的复合材料具有最高的弯曲强度,而CPS处理的复合材料具有最佳的冲击韧性和断裂伸长率。     

新型硅氧烷离子液体[MeBim][PF_6]的合成研究

本文以咪唑、四丁基溴化铵,碘甲烷、(γ-氯丙基)三甲氧基硅烷、六氟磷酸钾为原料合成了一种新型的硅氧烷离子液体—1-甲基-3-(γ-氯丙基)三甲氧基硅烷咪唑六氟磷酸盐,并对其合成反应条件进行了探索,通过红外光谱法(IR),确定了其结构。     

绿色合成3-异氰酸酯基丙基三甲氧基硅烷的研究

采用氰酸钾和3-氯丙基三甲氧基硅烷为原料,以氰化法合成3-异氰酸酯基丙基三甲氧基硅烷.确定了最佳工艺条件:反应温度105℃,催化剂用量1％,投料比n KOCN︰n3-氯丙基三甲氧基硅烷=2.5,保温时间4 h,保护试剂为己内酰胺,最佳用量n己内酰胺︰n3-氯丙基三甲氧基硅烷=1.6,溶剂为N-甲基甲酰胺,添加量为45％...     

黄铜表面硅烷自组装膜在氯化钠溶液中的耐蚀性

采用自组装技术在黄铜表面分别制备γ-巯基丙基三甲氧基硅烷(PropS-SH)、十二烷基三甲氧基硅烷(DTMS)、氨基丙基三甲氧基硅烷(APS)和γ-氯丙基三甲氧基硅烷(CPTMS)自组装膜,并分别采用电化学极化法、接触角测试和傅里叶红外光谱研究硅烷膜的耐蚀性、疏水生和结构.结果表明:经PropS-SH、DTMS和CPT...     

硅烷单体改性环氧树脂的固化及性能

分别用苯基三甲氧基硅烷(PTMS)和3-缩水甘油醚氧丙基三甲氧基硅烷(KH560)单体对环氧树脂进行了化学改性,通过红外(FT-IR)、核磁(1H NMR)对其化学结构进行了表征。以聚酰胺650为固化剂,用差示扫描量热仪(DSC)研究了固化物的固化动力学。此外还研究了涂膜的热失质量(TGA)、吸水率、附着力等性能。结果表明:苯基三甲氧基硅烷和3-缩水甘油醚氧丙基三甲氧基硅烷接枝上环氧树脂,与纯环氧树脂相比,改性后的树脂具有更好的热稳定性和更低的吸水率。改性环氧树脂固化后形成两面性质不同的涂层,与底材接触的涂层底面保留了环氧树脂原有的附着力,而涂层表面则具有高憎水性,起到防腐等作用。     

老化时间对桥联聚硅氧烷涂层防腐性能的影响

为提高涂层防腐蚀性能,以3-环氧丙氧丙基三甲氧基硅烷(GPTMS)和N-(3-三甲氧基硅基丙基)乙二胺(NTMDA)为原料,经环氧-胺基开环反应得到含羟基有机桥联硅烷前驱体(GN)。然后,前驱体GN在乙酸催化下制得硅烷溶胶。最后,将硅烷溶胶以浸渍-提拉方式沉积在Q235钢片上,得到含羟基桥联聚倍半硅氧烷涂层。用极化曲线和电化学阻抗谱等技术对涂层的防腐蚀性能进行评价,重点探究了胶体老化时间对涂层防腐蚀性能的影响规律。结果表明:当胶体老化时间为4 h时,涂层在低频0.01 Hz处的电化学交流阻抗相较于空白钢片高出1.5个数量级,具有优异的防腐蚀性能。另外,涂层附着力级别为1级。     

有机桥连聚倍半硅氧烷光学防潮涂层的制备

以巯丙基三甲氧基硅烷(MPTMS)和3-(甲基丙烯酰氧)丙基三甲氧基硅烷为(MATMS)为原料,经巯-烯点击反应制备有机桥连硅烷前驱体3-三甲氧硅基丙基-2-甲基-3-[(3-三甲氧硅基)丙基硫代]丙酸酯(MPMA).采用溶胶-凝胶法,MPMA在酸性条件下水解-缩聚得到溶胶,将其分别沉积在载玻片和聚醚酰亚胺(PEI)上...     

Dispersibility in organic solvents of nanosized silica particles used in semiconductor package substrates

This study examined the influence of different types of silane coupling agents on the dispersion of nanosilica particles with diameters of ca. 10 nm and 25 nm in two organic solvents, methylisobutylketone (MIBK) and cyclohexanone (CXN). The nanosilicas were prepared by the sol–gel process, and the following coupling agents were used: 3-glycidylpropyltrimethoxysilane (EpoSi), N-phenyl-3-aminopropyltrimethoxysilane (AmiSi), 3-mercaptopropyltrimethoxysilane (MerSi), and alkyltrimethoxysilane (AlkSi). While the 25-nm silica particles displayed dispersibility similar to that of submicron silica particles (ca. 150 nm and 250 nm), the dispersibility of the 10-nm silica particles proved to be dependent on the combinations of the agents and solvents; for example, EpoSi and MerSi were found to be suitable agents for MIBK and CXN, respectively. The slurries were also subjected to heating at 40 °C for 24 h, which resulted in a considerably higher stability of the dispersion state when CXN was employed as the solvent, regardless of which silica coupling agents were used. FTIR measurement revealed the presence of unreacted free Si–OH at 3740 cm⁻¹ for some nanosilicas. Combustion of the organic moieties introduced onto the silica surfaces also proved that the amount of organic groups present in a unit surface area of the nanosilicas were only 1/3 or 1/2 of that found on submicron silicas. From these observations, the low dispersibility of the nanosilicas was inferred to be due to the imperfect coverage of the silanol groups by the silane coupling agents.     

Effects of decomposition-treatment temperature on infiltration pressure of a surface modified nanoporous silica gel

When a nanoporous silica gel surface modified by silyl groups is decomposition-treated at a relatively low temperature, while the network is stable, the organic surface layers can be deactivated. As a result, the degree of hydrophobicity, which can be measured by the liquid infiltration pressure, is lowered. The infiltration and defiltration behaviors of liquid are dependent on the controlled decomposition-treatment time, the liquid composition, as well as the testing temperature. By adding electrolyte or using higher testing temperature, the infiltration pressure can be increased and the defiltration can be promoted.     

Crosslinked epoxy microspheres: Preparation,surface‐initiated polymerization,and use as macroporous silica porogen

In this article, we report the preparation of crosslinked epoxy microspheres with diameters of 5–10 μm prepared via phase‐inverted phase separation induced by polymerization in the thermosetting blend of epoxy and poly(ε‐caprolactone). The surfaces of the epoxy microspheres were functionalized to bear 2‐bromopropionyl groups, which were further used as initiators to obtain poly(glycidyl methacrylate) (PGMA) grafted epoxy microspheres via the surface‐initiated atom transfer radical polymerization approach. The PGMA‐grafted epoxy microspheres were then employed to react with 3‐aminopropyltrimethoxylsilane (APTMS) to obtain the functionalized epoxy microspheres, the surface of which contained a great number of trimethoxysilane groups. A co‐sol–gel process between the APTMS‐functionalized epoxy microspheres and tetraethoxysilane was performed, and organic–inorganic glassy solids were obtained. The organic–inorganic glasses were used as precursors for accessing macroporous silica materials via pyrolysis at elevated temperatures. The hierarchical porosity of the resulting macroporous silica was investigated by means of field emission scanning electronic microscopy, transmission electronic microscopy, and surface‐area Brunauer–Emmett–Teller (BET) measurements. We found that the macroporous silica possessed BET surface areas in the range 183.9–235.2 m²/g, depending on the compositions of their precursors. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Corrosion behavior of aluminum/silica/polystyrene nanostructured hybrid flakes

The corrosion protection of aluminum flake pigments has been extended by means of an encapsulating inorganic/organic silica/polystyrene hybrid nanolayer. A silica nanolayer encapsulated the surface of aluminum flakes (Al) by hydrolysis and polycondensation of tetraethylorthosilicate via sol–gel process to yield Al/Si flakes. Then, 3-methacryloxypropyltrimethoxysilane (MPS) was used as surface modifier which has polymerizable groups to participate in polymerization reaction (Al/Si/MPS). A polystyrene (PS) coating layer was applied on Al/Si/MPS flakes by free radical polymerization of styrene initiating with Azobisisobutyronitrile at 60 °C and subsequent washing of free chains with solvent yielded Al/Si/PS flakes. Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy and scanning electron microscopy showed that silica and PS nanolayers were formed on the aluminum flakes. The attached PS chains on the surface were detached by hydrofluoric acid aqueous solution and analyzed by gel permeation chromatography (GPC). Also, a transmission electron microscopy image showed clearly that the encapsulating layers are in the scale of nano. Good results were obtained in terms of corrosion protection in acidic and alkaline solutions, indicating that the silica/polymer hybrid nanolayer coating acts as an efficient protective film. After encapsulating the flakes, the evolved hydrogen volume was dropped and hybrid nanolayer resulted in no evolved hydrogen volume.     

One-pot synthesis and modification of silica nanoparticles with 3-chloropropyl-trimethoxysilane assisted by microwave irradiation

Industry and academia have shown great interest in the synthesis of organic–inorganic hybrid material because the modification of inorganic supports with organic groups increases the options for using these materials. Microwave irradiation as a heat source is an alternative tool compared with conventional heating (oil bath or furnace) to reduce the reaction times during the synthesis of these materials. Thus, the purpose of this work was to synthesize an organic–inorganic hybrid material, more specifically silica nanoparticles modified with 3-chloropropyl-trimethoxysilane, using microwave irradiation as the heat source. The hybrid materials were synthesized using the sol–gel method, with microwave irradiation for 10, 25, and 40?min, at 300?W of power and temperature of 40, 60, and 80°C. Elemental analyses, FTIR, and N₂ adsorption–desorption isotherms were developed to characterize the materials. It can be concluded that when microwave irradiation is used as a heat source, the reaction rate is accelerated and the surface area of hybrid materials increases considerably.     

Preparation and anticorrosive properties of hybrid coatings based on epoxy‐silica hybrid materials

A series of sol‐gel derived organic–inorganic hybrid coatings consisting of organic epoxy resin and inorganic silica were successfully synthesized through sol‐gel approach by using 3‐glycidoxypropyl‐trimethoxysilane as coupling agent. Transparent organic–inorganic hybrid sol‐gel coatings with different contents of silica were always achieved. The hybrid sol‐gel coatings with low silica loading on cold‐rolled steel coupons were found much superior improvement in anticorrosion efficiently. The as‐synthesized hybrid sol‐gel materials were characterized by Fourier‐transformation infrared spectroscopy, ²⁹Si‐nuclear magnetic resonance spectroscopy and transmission electron microscopy. Effects of the material composition of epoxy resins along with hybrid materials on the thermal stability, Viscoelasticity properties and surface morphology were also studied, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Mesoporous ordered silica structures modified by metal organic reagents and their application in catalytic Michael additions

Periodic mesoporous silica was modified with metal organic reagents via direct surface substitution reactions, thus introducing functional groups into the channels of the structure. Using materials functionalised with basic aromatic molecules as catalysts, the efficient Michael addition of diethyl malonate to trans-β-nitrostyrene was achieved. The catalysts anchored to the silica surface show high activity in the catalytic process even at low concentrations and low temperatures. The catalysts also prove to be stable during many recycling procedures. In combination with the remarkably reduced cost for the synthesis of these solid bases, the new hybrid systems are promising candidates for a new generation of catalysts.     

环孢菌素A柱层析硅胶再生工艺

环孢菌素A工业化生产涉及真菌发酵、萃取、浓缩、结晶、硅胶柱层析、脱色、二次结晶等步骤,目前硅胶柱层析步骤的硅胶只能一次使用,现实生产过程产生了大量的废硅胶,环保处理压力大、企业成本高。据此本文开展了环孢菌素A柱层析硅胶再生工艺研究,针对硅胶上吸附的杂质性质,研究了硅胶再生洗脱溶剂系统,通过响应面法优化再生条件,结果表明：选用含有0.26%聚山梨醇的乙醇反向冲洗4个柱体积,再使用双氧水浓度为0.15%的去离子水正向冲洗2.1个柱体积,冲洗流速为5mL/min;使用压缩空气将再生后的硅胶压出,烘干至水分含量为6%。按照本方法得到的再生硅胶按原工艺使用时,环孢菌素A回收率完全达标,并且可以三次重复使用达标。本研究建立了一套切实可行的环孢素纯化硅胶再生工艺,可有效节约工厂生产成本和减轻环境压力。     

Composites prepared from silica gel and furfuryl alcohol with p-toluenesulfphonic acid as the catalyst

Summary Composites of furfuryl alcohol and silica gel or Aerosil were prepared using p-toluenesulphonic acid as catalyst at room temperature. The molar ratio furfuryl alcohol/p-toluensulphonic acid was varied between 64.7 and 10. The surface of silica gel was partially coated when composite was prepared with the lower quantity of acid while the use of the higher proportion of acid produces the start of particle agglutination. The thickness of the polymer layer completely coating the surface of the composites ranged between around 10 to 39 ?. Preliminary results suggest that composites could be used as adsorbent of organic pollutants from water.     

Quaternary Ammonium Salts (QAS) Modified Polysiloxane Biocide Supported on Silica Materials

Three types of silica particles modified with vinyl groups were obtained: (i) xerogel formed by hydrolytic polycondensation of the mixture of tetramethoxysilane (TMOS) and 1,1,1,7−tetramethoxy-3,5,7-trimethyl-3,5,7-trivinyltetrasiloxane, (ii) mesoporous silica obtained from the same precursors in the presence of the cetyltrimethylammonium bromide (CTAB), and (iii) commercial Fluka silica gel 60A with a vinyltriethoxysilane-treated surface. Vinyl groups on these silica materials were transformed into silyl chloride by hydrosilylation with HMe₂SiCl. These groups were used to graft living polysiloxane that was synthesized by anionic ring-opening polymerization of 2,4,6-tri(3-chloropropyl)-2,4,6-trimethylcyclotrisiloxane and initiated by BuLi. Chloropropyl groups on the grafted polymer were used to quaternize N,N-dimethyl-n-octylamine. Silica particles with grafted polysiloxane having quaternary ammonium salt (QAS) groups pendant to polymer chains were obtained. Silica material with QAS groups directly attached to the surface were generated by the action of N,N-dimethyl-n-octylamine on particles obtained by the sol–gel process involving tetraethoxysilane (TEOS) with 3-chloropropyltriethoxysilane. The bacteriocidal properties of all these materials were tested in water suspension against five representative strains for Gram-positive and Gram-negative bacteria. Some of the silica–polysiloxane hybrid materials have good antibacterial properties against Gram-positive strains, but not as good as the non-tethered QAS-substituted polysiloxane in water solution. The QAS groups that are directly bonded to the silica material surface are inactive.