聚苯乙烯-铂络合物催化硅氢加成反应机理的研究

将巯甲基化交联聚苯乙烯－铂络合物微球用于催化苯乙烯与甲基二氯硅烷的加成反应，考察了用硅氢加成试剂处理催化剂的时间对其催化行为的影响。发现催化活性中心主要是Pt（Ⅱ），催化剂的后处理时间明显影响硅氢加成反应的诱导期和活性，并根据实验结果提出了可能的催化机理。     

4A分子筛固载铂催化剂催化乙炔硅氢加成反应

研究了4A分子筛固载铂催化剂的制备及其催化乙炔与三乙氧基硅烷硅氢加成反应的反应规律,考察了反应温度、原料配比、催化剂铂含量、乙炔流量等对反应的影响.结果说明4A分子筛固载铂催化剂对乙炔与三乙氧基硅烷硅氢加成反应具有较好的催化活性,并且反应条件温和,催化剂回收利用3次仍具有较高的活性.     

高分子金属络合催化剂PS—SH—Pt在硅氢加成反应中的应用

本文报导了巯甲基化交联聚苯乙烯铂铬合物ＰＳ－ＳＨ－Ｐｔ在甲基二氯硅烷与不饱和单体硅氢加成反应中的应用，并对其催化活性，选择性及回收再用性进行了研究。     

零价铂催化剂的制备及其在硅氢加成中的应用

以氯铂酸和二乙烯基四甲基二硅氧烷为原料,采用还原-配合法制得零价铂催化剂,并对催化剂的含量及其催化硅氢加成反应后体系的黏度、环氧值、反应效率(剩余氢质量分数)等性能进行表征。结果表明,该铂催化剂的催化活性和效率高,经济实用,其催化的硅氢加成反应产物的黏度和环氧值均保持稳定,进而可改善产品外观和稳定性。     

高活性硅氢加成反应用催化剂的合成及应用

以氯铂酸、四甲基二乙烯基二硅氧烷为原料，合成了氯铂酸-乙烯基硅氧烷配合物；并采用红外跟踪的方法，通过观察红外光谱中Si-H键的特征吸收峰的强弱变化，考察了该配合物对含氢硅油与4，4’-二烯丙氧基二苯砜（ABPS）的硅氢加成反应的催化活性；同时，用^1H NMR谱图表征了产物的结构。结果表明，该配合物能催化ABPS与舍氢硅油的硅氢加成反应，在该反应中其催化活性高于氯铂酸-异丙醇、氯铂酸-四氢呋喃及氯铂酸-乙烯基硅氧烷配合物。     

聚γ—巯丙基硅氧烷铂（Ⅱ）配合物的合成及其催化硅氢化性能

γ－巯丙基三乙氧基硅烷用气相法二氧化硅固载,再与氯亚铂酸钾作用,合成了聚γ－巯丙基奎氧烷铂（Ⅱ）配合物。研究了该了该梧全物对烯烃与三乙氧基硅烷的硅氢加成反应的催化特性。     

合成γ—甲基丙烯酰氧丙基三甲氧基硅烷的催化剂体系的研究

本文比较了氯铂酸－异丙醇（Ｉ）、氯铂酸－四氢呋喃（Ⅱ）和氯铂酸－乙酰丙酮（Ⅲ）三种铂络合物催化剂对甲基丙烯酸烯丙酯与三甲氧基硅烷的硅氢加成反应的催化性能，探讨了各种可能因素对反应凝胶的影响，考察了反应条件对催化活性和反应结果的影响。实验结果表明三种催化剂都具有较高的活性，但催化剂的络合结构状态与反应是否凝胶有关，催化剂（Ⅲ）诱导期短，反应平稳，不易引起凝胶，用催化剂（Ⅲ）合成γ－甲基丙烯酰氧丙基三     

金属-有机框架材料在硅氢加成反应中的应用研究进展

硅氢加成反应是指在一定条件下含有硅氢键的化合物与含不饱和键的化合物进行的加成反应，是构筑C—Si键的重要反应之一，在有机硅工业中具有举足轻重的地位。该文综述了近年来金属-有机框架（MOFs）材料催化不饱和烃、羰基化合物和CO2的硅氢加成反应的研究进展，并针对每一种反应底物进行系统地总结与评述，最后指出了MOFs材料用于催化硅氢加成反应存在的问题，并对其未来发展方向进行了展望。     

一种含羟基的微孔聚硅氧烷固体颗粒的制备与表征

随着有机硅高分子聚合物在化学领域的广泛应用,如何设计合成含有新型功能官能团的有机硅高分子聚合物逐渐成为其主要的发展方向,设计合成出了一种新的含有羟基的聚硅氧烷固体颗粒(POS-OH),合成方法较为简便.具体为以甲基二乙氧基氢硅烷(含三乙氧基氢硅烷)与丙烯醇为原料在铂催化剂催化下,在90℃的油浴中进行硅氢加成反应20h生...     

铂催化硅氢加成反应研究进展

硅氢加成反应是合成有机硅材料最重要的途径之一,铂催化剂作为其应用最广的催化剂,具有重要的意义。本文首先介绍了硅氢加成反应机理的研究现状;分析了聚合物长链段铂配合物、含多个铂原子铂簇化合物及N-杂环卡宾铂配合物均相铂催化剂的研究进展,致力于改善均相催化剂催化选择性差、催化活性难以控制等缺点;分别阐述了不同铂催化剂载体如无机二氧化硅、炭载体、金属氧化物、有机高分子、固载液等作为铂催化剂载体的优点,负载铂催化剂具有可回收、产物选择性好的优点,有效解决了工业上铂损失的问题;最后对铂催化硅氢加成反应的发展趋势进行了展望分析,铂负载能力的提高、铂负载催化剂的分离、硅氢加成反应的原理、催化范围的扩大等均是今后研究的重要方向。     

Interfacial shear strength and durability improvement by monomeric and polymeric silanes in basalt fiber/epoxy single-filament composite specimens

Silane coupling agent effects in basalt fiber-epoxy systems have been investigated through measurement of the interfacial shear strength (IFSS) in single-fiber composite (SFC) specimens. Three silane were studied: 3-aminopropyltriethoxysilane (APS) and two polymeric silanes in which dimethoxy- or trimethoxysilane groups are attached via side chains to a polyethyleneimine backbone. Optimal conditions for silane application were standardized. Crosslinking of the deposited silanes is shown to result in decreased interpenetration by the matrix epoxy resin and lower values of IFSS. The polymeric silane with trimethoxy groups was found, as expected, to be inferior to the other two. APS and the polymeric dimethoxysilane gave similar results in improvement of IFSS and its retention after 1 h boiling in water. Monitoring of acoustic emission (AE) during straining of SFC specimens established a one-to-one correspondence between the number of AE events and fiber breaks. Measurement of AE pulse energies provided evidence for the sizing effect of polymeric silane coatings, through healing of surface flaws, as well as for moisture attack at severe surface flaws on the fiber during silane treatment.     

Interfacial adhesion in polyester resin concrete

Silane coupling agents are widely used to improve the interfacial adhesion between the inorganic filler and the organic polymer matrix of polymer concretes. The mechanical properties of the concretes are also found to improve on the addition of silane coupling agents. This paper compares two methods of silane application; pretreatment of aggregates with silane and direct addition of silane to the resin, on the interfacial adhesion in polyester resin concrete for three different silanes. The effects of other parameters, such as the silane loading, predrying of aggregates before silane treatment, addition of CaCO₃ microfiller and pH of the silane treatment medium, are also investigated.     

Mineral filler reinforcement for commingled recycled‐plastic materials

Three types of mineral fillers, gypsum, wollastonite, and talc, were investigated for their ability to modify the mechanical properties of commingled recycled‐plastic composites containing 0.07–0.26 v/v of filler. Mechanical test results showed that the talc reinforced composites were significantly better in mechanical properties when compared with the gypsum and wollastonite composites. Scanning electron microscopy (SEM) showed that gypsum formed large agglomerates in the matrix. Interfacial adhesion between filler and matrix was evaluated using simple empirical models. To enhance the adhesion, talc, and wollastonite were pretreated with silane coupling agents, 3‐methacryloxypropyltrimethoxy silane (γ‐MPS) and 3‐aminopropyltriethoxy silane (γ‐APS). This did not result in any significant improvement to the material properties. The γ‐APS treatment, however, increased the tensile properties of the composites by ～ 5% when compared with the γ‐MPS treatment. The SEM investigations showed that the γ‐APS treatment provided better adhesion of filler particles and hence voids were less likely to form in the matrix when compared with the γ‐MPS composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Adhesive Bonding of Oil-Contaminated Steel Substrates

Durability of adhesive bonds formed by curing epoxies against oil-contaminated steel substrates using amidoamine curing agents was determined during exposure to boiling water. The most durable bonds were obtained using amidoamine curing agents with relatively low amine numbers and by blending silane coupling agents such as γ-glycidoxypropyltrimethoxysilane (γ-GPS) and N-(2-aminoethyl)-3-aminopropyltrimethoxy silane (AAMS) into the adhesives. When X-ray photoelectron spectroscopy (XPS) was used to characterize the failure surfaces of the adhesive joints after exposure to boiling water, it was determined that adhesives prepared using amidoamine curing agents with low amine numbers were able to displace the oil from the steel surface but adhesives prepared with amidoamine curing agents with high amine numbers were not. Results obtained from XPS also showed that the amino groups on the substrate fracture surfaces of joints prepared using curing agents with low amine numbers were protonated whereas the amino groups in the bulk adhesive were not, indicating that there was a chemical interaction between the curing agent and the hydrated surface of the substrate. It was also shown using infrared spectroscopy that the amidoamine curing agents formed salts with calcium compounds in the oil.     

Adhesive Bonding of Oil-Contaminated Steel Substrates

Durability of adhesive bonds formed by curing epoxies against oil-contaminated steel substrates using amidoamine curing agents was determined during exposure to boiling water. The most durable bonds were obtained using amidoamine curing agents with relatively low amine numbers and by blending silane coupling agents such as γ-glycidoxypropyltrimethoxysilane (γ-GPS) and N-(2-aminoethyl)-3-aminopropyltrimethoxy silane (AAMS) into the adhesives. When X-ray photoelectron spectroscopy (XPS) was used to characterize the failure surfaces of the adhesive joints after exposure to boiling water, it was determined that adhesives prepared using amidoamine curing agents with low amine numbers were able to displace the oil from the steel surface but adhesives prepared with amidoamine curing agents with high amine numbers were not. Results obtained from XPS also showed that the amino groups on the substrate fracture surfaces of joints prepared using curing agents with low amine numbers were protonated whereas the amino groups in the bulk adhesive were not, indicating that there was a chemical interaction between the curing agent and the hydrated surface of the substrate. It was also shown using infrared spectroscopy that the amidoamine curing agents formed salts with calcium compounds in the oil.     

Synthesis of Organosilane‐Modified Carbon Nanofibers and Influence of Silane Coating Thickness on the Performance of Polyethylene Nanocomposites

Silane coatings with different thicknesses were synthesized on CNFs for reinforcement of polyethylene composites. The thickness of the silane coating was adjusted by using a basic catalyst to increase the overall reactivity of the silane groups, resulting in a thick coating of ≈46 nm (ca. 90% increase in fiber diameter). DMA performed on the polyethylene composites showed a substantial increase in storage modulus from 1.68 to 2.34 GPa (40%) at low temperatures in the composite with the thick silane coating (≈46 nm) at a low loading of 0.4 wt.‐%. We believe that the silane‐treated nanofillers with thick coatings are very promising for high‐performance nanocomposites with non‐polar polymer matrices.

     

反应挤出法制备高熔体强度聚丙烯的研究

采用不饱和硅烷为接枝单体,不饱和烯烃为交联助剂,在双螺杆挤出机上一步法实现了均聚型聚丙烯(PP)的接枝交联,制得了高熔体强度PP。结果表明,接枝单体、交联助剂、引发剂均显著地影响PP的熔体流动性能。在硅烷和交联助剂共存的条件下,PP的熔体流动性能随引发剂过氧化苯甲酰(BPO)用量的增加而下降。交联助剂起到稳定大分子自由基的作用,增加了硅烷的接枝效率和接枝速率;并指出硅烷接枝交联法是目前制备高熔体强度PP方法中最有希望实现工业化生产的技术。     

硅烷偶联剂改性玻璃微珠用于不饱和聚酯树脂

采用乙烯基、甲基丙烯酰氧基和环氧基3类硅烷偶联剂对中空和多孔两种玻璃微珠进行了改性,将其用于不饱和聚酯树脂复合材料。利用红外光谱(FTIR)、核磁共振谱仪(NMR)和扫描电镜(SEM)技术,结合力学性能测试对其改性机理进行了分析。结果表明,硅烷偶联剂不改变微珠和不饱和聚酯树脂基体的本体结构。硅烷偶联剂非极性端含有C==C双键,使玻璃微珠具有较大的表面张力,且与不饱和树脂相似的双键使其易于结合;此外,非极性端的链长较长,使其与树脂形成的过渡层具有良好的空间柔软性。对于相同非极性端的硅烷偶联剂,极性端含有大基团的偶联剂与玻璃微珠的结合效果较弱。微珠的均匀外形有益于它与树脂的结合。     

Development of bio-based hybrid resin,from natural lacquer

Preparation and structure analysis of a bio-based hybrid material composed of natural lacquer, epoxy, and organic silane compounds were investigated using liquid and solid-state nuclear magnetic resonance. The good composition of additives in the hybrid was determined by the drying, hardness, and resin-molding properties. Although natural lacquer alone cannot form thick resins, this bio-based hybrid material showed good resin formation at room temperature without thermal treatment. This result could be based on the enhancement of curing by the sol–gel reaction between natural lacquer and the organic silane compound, and a crosslink reaction between organic silane and epoxy groups. At the same time, oxidative polymerization at the unsaturated side chains in the urushiol was enhanced by the sol–gel reaction because the catechol hydroxyl groups, which have an antioxidative property, reacted with the organic silane. In addition, this bio-based resin possesses a thermoset property because curing of the hybrid was improved by thermal treatment. Based on the structure analyses, the sol–gel reaction between urushiol and organic silane compound proceeded immediately, indicating the high reactivity of this sol–gel reaction. On the other hand, the reaction between bisphenol A-type epoxy resin and the organic silane seems to progress slowly after the epoxy ring opening. In addition, a sol–gel reaction occurred between the amine group in the organic silane and the hydroxyl group formed after the crosslink reaction of the epoxy group. These results suggested that the improvement in drying and molding properties of the hybrid was based on the chemical reactions among all components (i.e., natural lacquer, epoxy, and organic silane).     

Effect of silanes on the morphology,hydrophobicity, and dynamical mechanical properties of polyimide/silica hybrid membranes

Polyimide (PI)/silica hybrid membranes with high contact angles were prepared through the in situ sol–gel process. The precursor, poly(amic acid) with controlled block chain length, was synthesized using 4,4′‐diaminodiphenyl ether (ODA), 3,3′,4,4′‐benzophenone‐tetracarboxylic dianhydride (BTDA) and 3‐aminopropyl‐trimethoxysilane (APrTMOS) or 3‐aminopropyldimethylethoxysilane (APDiMOS). And then, phenyltrimethoxysilane (PTS) or tetramethoxysilane (TMOS) or methyltrimethoxysilane (MTrMOS) was respectively, added to the above polyamic acid and mixed thoroughly. Following curing reaction, the PI/silica hybrid membranes with different cross‐linkages, silica content, and hydrophobic properties were prepared. The effect on the formation of PI imide ring during imidization reaction is increased as the increase of silanes content and characterized by frequency shiftment and absorbance ratio of Fourier transform infrared (FTIR) measurements. All the hybrid membranes show high transparency though with high silica contents. The storage modulus, tan δ, and damping intensity by DMA measurements are all correlated with silane content or block chain length. And all these membranes with silane content possess high contact angle as compared to pure PI without any silanes added and the contact angles increase with increasing the silane content. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011