有机硅防护剂对铝酸盐水泥砂浆防护性能的影响

采用接触角测试仪、红外光谱(FTIR)仪、X射线衍射(XRD)仪、扫描电子显微镜(SEM)表征和分析了有机硅烷涂覆量对铝酸盐水泥砂浆防护性能的影响规律.结果表明:采用1次涂覆方式时,铝酸盐水泥砂浆试件的吸水率随有机硅烷涂覆量的增加先降低后趋于稳定,吸水率均降低90%以上,符合规范要求;铝酸盐水泥砂浆试件接触角随有机硅烷涂覆量的增加先增大后减小,试件表面由亲水性变为疏水性,当有机硅烷涂覆量为250g/m~2时砂浆试件接触角达142.66°;有机硅烷渗透深度随涂覆量的增加先增加后减少,当有机硅烷涂覆量为250g/m~2时其渗透深度可达10.73mm.机理分析表明,有机硅烷与铝酸盐水泥砂浆只是在毛细孔内壁发生了水解缩合反应,形成了网状硅氧烷憎水膜层,并未形成新的物质.     

One‐Step Synthesis of Superbright Water‐Soluble Silicon Nanoparticles with Photoluminescence Quantum Yield Exceeding 80%

Fluorescent silicon nanoparticles (SiNPs) have shown potential applications in bioimaging/biolabelling, sensing, and nanomedicine/cancer therapy due to their superior properties such as excellent photostability, low cytotoxicity, and versatile surface modification capability. Here, a simple, high‐yield, and one‐pot method is developed to prepare superbright, water‐soluble, and amine‐functionalized SiNPs with photoluminescence quantum yield (PLQY) comparable to fluorescent II–VI semiconductor quantum dots (QDs) but with much lower cytotoxicity. By introducing a commercially available amine‐containing silane molecule, N‐[3‐(trimethoxysilyl)propyl]ethylenediamine (DAMO), water‐soluble SiNPs are prepared with PLQY of 82.4% via a microwave‐assisted method. To the best of our knowledge, this is the highest PLQY value ever reported for water‐soluble fluorescent SiNPs. The silicon element in our SiNPs is mainly four‐valent silicon and thus these SiNPs may also be termed as oxidized silicon nanospheres or silica nanodots. We have also demonstrated the importance of the silane structure (e.g., a suitable amine content) on the photoluminescence property of the prepared SiNPs. As revealed by the time‐resolved photoluminescence technique, the highest PLQY value of DAMO SiNPs is correlated with their monoexponential decay with a relatively long fluorescence lifetime. In addition, the potential use of these SiNPs has also been demonstrated for fluorescent patterning/printing and ion sensing (including Cu²⁺ and Hg²⁺).     

两亲性硅烷辅助水热合成具有介孔结构的TS-1分子筛

采用两亲性有机硅烷作为介孔模板剂、小分子有机胺为微孔导向剂一步法水热合成出了多级孔道TS-1分子筛.采用XRD、UV-vis、FT-IR、N2吸附、SEM、MAS NMR和TGA手段对合成样品进行了结构表征,同时考察了其催化氧化性能.结果表明,所合成样品除微孔范围内的0.55 am孔道外,还拥有孔径为3.7nm的均一介孔孔道;相比于常规TS-1,此样品拥有较为疏水的表面.与常规TS-1相比,在催化环己烯环氧化反应中,多级孔道TS-1凭借拥有中孔孔道,得到近两倍的转化率;同时由于多级孔道TS-1的表面羟基较少,有效地避免了环氧化产物的开环反应,因此环氧化物的选择性也是常规TS-1的2倍.     

In Situ FTIR Study of the Formation of an Organosilane Layer at the Silica/Solution Interface

An FTIR experiment especially designed to study the growth of an organosilane layer at the interface between a solution and a flat silica surface is presented. High sensitivity is achieved by using the attenuated total reflection (ATR) technique in a liquid flow cell. The ATR crystal, either silicon or germanium, is covered with a very thin silica layer. Chemical reactions of a mono-and a di-hydrolyzable silane with the silica substrate have been investigated. The grafting of a submonolayer of the first reagent has been monitored by following the C-H and SiO-H vibrations. The density of grafted molecules has been estimated and information on the nature of the chemical bonding has been achieved. Evidence for the chain-polymerization of the dihydrolyzable silane at the substrate/solution interface has been inferred from the appearance of a Si-O-Si absorption band.     

基于自组装技术的单晶硅表面镀铜工艺

本研究在单晶硅基底表面自组装制备了3-氨丙基三乙氧基硅烷(APTES)自组装薄膜,并在此基础上进行化学镀和电镀研究,最终得到了致密均匀的铜膜,镀层与单晶硅基底通过配位键连接,粘结力强。利用循环伏安(CV)法探索得到了最佳电镀工艺参数为:电流密度1.56A/dm2,电镀时间600s。借助接触角测试仪测定了不同试样表面的润湿性,通过X射线能谱仪(EDX)、扫描电子显微镜(SEM)对镀层的元素含量和表面形貌进行了表征。获得的铜镀层致密均匀并呈现金属光泽。     

Macro- and nanotribological properties of organosilane monolayers prepared by a chemical vapor adsorption method on silicon substrates

Organosilane monolayers are novel ultrathin films used to control the physicochemical properties, such as friction and wear, of solid surfaces. In this study, the authors prepared alkylsilane and fluoroalkylsilane monolayers with a series of chain lengths by a chemical vapor adsorption method. The monolayers tribological properties were investigated by lateral force microscope (LFM) and friction tester. LFM nanoscale measurements of tribological properties showed that alkylsilane monolayer gave lower lateral force than the Si substrate surface. The lateral force decreased as the length of the alkyl chain increased. On the macroscale, friction test revealed that the organosilane monolayers gave lower dynamic friction coefficients than the Si substrate surface in air at room temperature. The longer the alkyl chain, the greater the wear resistance of the organosilane monolayers. Friction experiments using tetradecane as a lubricant showed better tribological properties than were obtained in air. Furthermore, microscopically line-patterned two-component organosilane monolayers were prepared and their macroscopic friction behavior was investigated. Even though the height difference between the two-components was less than 1 nm, friction force anisotropy between the parallel and perpendicular directions against the line pattern was observed.     

有机硅高沸物甲乙氧基双酯化工艺研究

主要对采用直接法生产有机氯硅烷单体过程中产生的大量高沸点废料的混合物进行甲氧基、乙氧基双酯化的工艺研究,确定了适于工业化生产的最佳工艺技术路线、原料配比、操作条件,开创了一条充分利用废料资源实现经济发展与生态保护"双赢"的绿色工艺。     

一种高附着力丙烯酸酯密封胶的制备

通过直接在丙烯酸酯乳液的合成过程中引入一定量的有机硅基团(Wz-B),配合后添加环氧基硅烷(Wz-A)的方式来提高水性丙烯酸酯密封胶产品的附着力。结果表明,两种硅烷搭配使用可以显著提高密封胶的力学性能和粘结性能,有效缩短密封胶的粘结形成时间。     

镀锌板复合钝化工艺的研究

以苯丙乳液、钼酸盐、植酸、有机硅烷等为主要原料制备了无铬钝化膜。采用醋酸铅点滴加速腐蚀实验(ASS)、中性盐雾腐蚀实验(NSS)研究了钝化液的组成、反应温度、搅拌时间等因素对膜层耐蚀性的影响,得出较优制备条件为:300 mL.L-1的苯丙乳液,12 mL.L-1的植酸溶液,80 mL.L-1的有机硅烷,60 mL.L-1的复合盐溶液,反应温度为30℃,搅拌时间为3 h;所制得的无铬钝化膜性能稳定,具有优良的耐腐蚀性能。