硅烷偶联剂表面修饰纳米氧化铝

硅烷偶联剂KH570在乙醇溶剂中以酸水溶液为催化剂进行水解后对纳米氧化铝进行湿法表面修饰改性。用灼烧法测定了粉体表面偶联包覆率,以此为指标研究了KH570的水解条件及其对偶联效果的影响。结果表明,酸种类等水解条件对偶联效果有很大影响;适宜的偶联剂水解条件为:草酸作催化剂,调pH值为3~4,室温下水解1h。适宜的纳米氧化铝表面修饰条件为:偶联剂质量分数4.5%,在45℃偶联5.5h。经红外光谱(IR)分析,氧化铝的偶联修饰机理为:硅烷偶联剂与纳米氧化铝表面的羟基发生化学键合,从而实现纳米氧化铝的表面修饰改性。改性纳米氧化铝在有机相中的分散性和稳定性均得到了改善。     

硅烷偶联剂原位包覆纳米TiO_2及其在PVC功能改性中的应用

通过原位聚合法在金红石型纳米TiO2表面包覆硅烷偶联剂,研究超声波处理时间、水浴时间及溶液的pH值对改性效果的影响。结果表明:当超声时间为60min、水浴时间为2h、溶液的pH=6时,其改性效果最佳;采用扫描电镜、X射线衍射、差示扫描量热分析法、紫外-可见分光光度计、氧指数测试仪等手段对试样进行表征,结果显示:纳米TiO2与偶联剂之间的结合为化学结合,改性后的纳米粒子分散性得到了提高,当纳米TiO2添加量为3%时,PVC/KH570-TiO2复合材料的阻燃性能与机械性能最佳。     

皂化P204微乳体系萃取大豆蛋白的研究

研究了NaOH皂化P204/正辛烷微乳体系萃取大豆蛋白的机理和工艺,考察了大豆加入量、P204的浓度、NaOH的浓度、萃取时间、水相pH值及离子强度等对大豆蛋白萃取率的影响。实验结果表明,该微乳体系萃取大豆蛋白的优化工艺条件为:大豆粉与微乳液的质量体积比1∶10,P204在油相中浓度0.8 mol/L,NaOH的浓度1.25 mol/L,萃取时间15 min,外水相pH值5,萃取率可达88.48%。通过调节水相pH和离子强度可实现大豆蛋白的萃取和反萃取。     

水性纳米硅溶胶的表面改性及其应用研究

将几种功能性有机硅烷偶联剂与不同pH值的无机纳米硅溶胶水溶液通过表面改性反应和溶胶-凝胶技术制备出水分散纳米杂化改性硅溶胶,并用透射电镜TEM和红外光谱FT-IR对其进行表征和分析,研究了硅烷偶联剂碳链长度及偶联剂用量、溶液pH值对改性硅溶胶稳定性的影响,初步探讨了其在水性涂料、水性纳米罩光防污涂料及砂浆防水中的性能和应用。     

微细导电粉体碘化亚铜在乙二醇中的分散性研究

研究了分散方法(球磨、高速剪切、起声波)、分散剂的种类(十二烷基苯磺酸、聚乙二醇、硅烷偶联剂、钛酸酯偶联剂)、分散剂的含量及分散时间对微细导电粉体碘化亚铜在乙二醇中分散性的影响。用SEM对其分散情况进行表征。并对其分散机理进行探讨及研究。结果表明。当采用球磨分散方法、分散荆为钛酸酯偶联剂。含量为1％。分散时间为8h可制得分散性良好的碘化亚铜／乙二醇体系。     

固相微萃取-气相色谱-质谱联用测定水中酚类化合物

建立了固相微萃取与气相色谱－质谱联用技术（SPME－GC－MS）测定水中酚类化合物的新方法，探讨了萃取时间、搅拌速度、离子强度、pH值和解吸时间等条件对萃取量的影响。结果表明：65μm PDMS/DVB涂层对水中的酚类化合物有较好的萃取效果，用于水中酚类化合物的测定，结果满意。     

自组装磁性聚苯乙烯微球固定化木瓜蛋白酶

通过逐层自组装（Layer-By-Layer self-assembly）的方式在自制的经过磺化的聚苯乙烯微球上连接高分子电解质和磁性物质制备了磁性微球,并用此磁性微球固定化木瓜蛋白酶。研究了固定化酶的最优工艺条件（固定化率最高）为：0.5g液态分散磁球(固含量为7.9%),温度30℃,给酶量15mg,pH值为6.0,固定化时间1.0h,此时可达非常高的固定化率93.0%。并且研究了固定化酶的性质：最佳使用温度为50℃,最佳使用pH值8.0,使用3次或80℃保存1.5~2.0h活性大约降为一半。     

季铵化聚乙烯亚胺的抗菌性能研究

采用叔胺化反应与季铵化反应两步高分子反应过程,制备了季铵化的聚乙烯亚胺(QPEI);以大肠杆菌(E.coli)为致病菌体,重点研究了高分子季铵盐QPEI的抗菌活性;采用平板活菌记数法考察了季铵化度及pH值等因素对其抗菌性能的影响规律;并采用β-半乳糖苷酶活性测定法,研究了QPEI的抗菌机理.研究结果表明,QPEI具有很强的抗菌能力,对浓度为109CFU/mL的菌悬液,在药剂量为15mg/L、接触时间为4min的条件下,杀菌率可达100%;QPEI的季铵化度对其抗菌性能影响很大,季铵化度越高,抗菌性能越好;在一定的pH值范围内,pH值越高,抗菌性能越好.β-半乳糖苷酶活性测定结果表明,QPEI的抗菌机理是基于杀菌过程,而不只是抑菌作用.     

PS/SiO2纳米复合粒子的制备及反应机理研究

采用一步法合成出PS/SiO₂纳米复合粒子,得到产物的产率和接枝效率均在95以上.与传统的预处理方法相比,一步法在工艺上简单易行,重复性好;复合粒子粒径、形态及分散状况与预处理方法无明显差别.对一步法制备中硅烷偶联剂的作用机理进行了探讨,通过调节偶联剂添加量可以使偶联剂在复合粒子中起到偶联剂或交联剂或二者兼有的作用.动力学研究表明,在实验配方条件下,反应遵循与前人类似工作截然不同的机理模型.此外,对复合粒子的形态与结构进行计算表明,在实验条件下,产物中平均每个复合粒子内含有5～6个初始的SiO₂纳米粒子,这些粒子团聚在一起形成核,PS接枝并包覆于团聚体外形成壳.     

氨基硅烷偶联剂改性凹凸棒土的制备及其吸附性能

采用双氨基硅烷偶联剂KH-792对盐酸改性凹凸棒土(HATT)进行改性,使用FTIR、TGA、DSC、XRD和BET等对目标产物(KHATT)进行了表征。 研究了KHATT对模拟水样中Cr(Ⅵ)的吸附性能,系统考察了模拟水样中Cr(Ⅵ)的初始浓度、pH值、吸附时间及KHATT用量等因素对Cr(Ⅳ)去除率的影响。 结果表明,在KHATT用量为3 g/L、吸附时间为40 min、pH值为5.5的条件下,KHATT对Cr(Ⅵ)的去除率最高,达85.15%;且KHATT经再生后第4次的吸附量仍可达到第1次吸附量的90%以上。 对吸附的过程和机理进行了初步探讨。     

Interaction of Silane Coupling Agents with CaCO3

A study of eight silane coupling agents showed very different effect of these compounds on the mechanical properties of PP/CaCO₃composites. The application of aminofunctional silane coupling agents resulted in the reactive coupling of the two inactive components leading to increased strength and decreased deformability. A detailed study of the interaction between CaCO₃and the various coupling agents was carried out in order to find an explanation for the strong coupling effect. The amount of coupling agent creating a monolayer coverage was determined by a dissolution method for each coupling agent. The obtained values changed between 0.3 and 1.0 wt% calculated for the CaCO₃. An attempt was made to determine the orientation of the adsorbed molecules to the filler surface. Most of the coupling agents are oriented perpendicularly to the surface with the exception of a methacryl functional silane compound. Possible interactions between hydrolyzed or condensed silane coupling agents and the filler were studied by Fourier transform infrared spectroscopy using transmitting (FTIR-TS) and diffuse reflectance (DRIFT) modes, as well as gel permeation chromatography (GPC). The results showed that bulky organofunctional groups form a caged, polycyclic, low-molecular-weight structure on the surface, while silanes with smaller groups tend to condense into open, ladder type, high-molecular-weight polysiloxane chains. Polymer/filler adhesion, however, depends primarily on the chemical character of the organofunctional group. Aminofunctional silane coupling agents adhere well to the filler surface and react also with the polymer. In the case of similar functionality the size of the organofunctional group determines the strength of the adhesion.     

Surface Modification of Poly(urea-formaldehyde) Microcapsules and the Effect on the Epoxy Composites Performance

The surfaces of poly(urea-formaldehyde) (PUF) were modified by γ -glycidoxypropyltrimethoxy silane (KH560) in order to improve the interfacial bonding between self-healing PUF microcapsules and epoxy matrix. The modification mechanism between PUF microcapsules and KH560 was studied. X-ray photoelectron spectra (XPS) analyses showed that the silane coupling agent molecular binds strongly to the surfaces of PUF microcapsules. Chemical bond (Si–O–C) and hydrogen bond were formed at interface by the reaction between Si–OH and the hydroxyl group of PUF microcapsules surface. The tensile and impact resistance tests revealed that strength and toughness of the composites was improved significantly. Furthermore, scanning electronic microscopy (SEM) photographs of the fractured surface confirmed that the silane coupling agent plays an important role in improving the interfacial performance between microcapsules and resin matrix.     

Acrylic polymer/silica organic–inorganic hybrid emulsions for coating materials: Role of the silane coupling agent

Acrylic polymer/silica organic–inorganic hybrid emulsions were synthesized by a simple method, that is, a conventional emulsion polymerization and subsequent sol–gel process, to provide water‐based coating materials. The acrylic polymer emulsions contained a silane coupling agent monomer, such as methacryloxypropyltriethoxysilane, to form highly solvent‐resistant hybrid films. On the other hand, the hybrid films from the surface‐modified polymer emulsions, in which the silane coupling agent was located only on the surface of the polymer particles and the particle core was not crosslinked, did not exhibit high solvent resistance. A honeycomblike array structure, which was derived from the polymer particles (diameter ≈ 50 nm) and the silica domain, on the hybrid film surfaces was observed by atomic force microscopy. The crosslinked core part and silane coupling agent containing the shell part of the polymer particles played important roles in attaining high solvent resistance. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4736–4742, 2006     

Effect of silane coupling agent on mechanical interfacial properties of glass fiber‐reinforced unsaturated polyester composites

A silane coupling agent, γ‐methacryloxypropyltrimethoxysilane, for the surface modification of glass fibers was varied between 0.1 and 0.8 wt %. To understand the role of interfacial adhesion of glass fiber/unsaturated polyester composites, contact angles of the silane‐treated glass fibers were measured by the wicking method on the basis of the modified Washburn equation with deionized water, diiodomethane, and ethylene glycol as testing liquids. As a result, silane‐treated glass fibers led to increased surface free energy, mainly because of their increased specific or polar component. The mechanical interfacial behaviors based on the interlaminar shear strength (ILSS) of the composites determined by short‐beam tests and the critical stress‐intensity factor (K_IC) were also improved in the case of silane‐treated composites. The surface free energy and the mechanical interfacial properties especially showed the maximum value in the presence of 0.4 wt % silane coupling agent. It revealed that the increase of a specific component of the surface free energy or hydrogen bonding between the glass fibers and the coupling agents plays an important role in improving the degree of adhesion at interfaces in a composite system. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 55–62, 2003     

Silane treatment in polypropylene composites: Adsorption and coupling

The study of the effect of eight silane coupling agents on mechanical properties of PP/CaCO₃ composites showed that the application of certain compounds leads to the reactive coupling of the components. The adsorption of the silanes on the surface of the filler was studied by a dissolution method, while the structure of the adsorbed layer was determined by FTIR spectroscopy and GPC measurements. Model reactions and an FTIR study were carried out to reveal possible coupling reactions of PP and the active silanes. The results showed that amino-functional silane coupling agents adsorb on the surface of the filler, polycondensation taking place and a polysiloxane layer of high molecular weight forms as a result. The model reactions indicated that during processing, PP oxidizes even in the presence of stabilizers and oxygen-containing functional groups form on the polymer chains. These easily react with the amino functionality of the silane coupling agents strongly bonding the polymer to the treated filler.     

Effect of different preparation methods on mechanical behaviors of carbon fiber-reinforced PEEK-Titanium hybrid laminates

This paper aims to investigate the mechanical behaviors of carbon fiber-reinforced PEEK-Titanium hybrid laminates (TiGr) prepared by different surface treatment conditions using silane coupling agent. In order to improve the bonding performance between the titanium sheets and PEEK, the titanium layers were subjected to sandblasting roughening and silanization treatment, the curing process was explored by setting different concentrations of silane coupling agent, curing temperatures and curing times. The optimum parameters of the process were determined by analyzing the mechanical properties of the laminates, which are 10% of SCA concentration, 130 °C of curing temperature and 1 h of curing time, and the corresponding tensile, bending and inter-laminar shearing strengths are 837, 1071 and 75 MPa, respectively. The surface composition, structures and chemical bonding of the modified titanium sheet were analyzed through Scanning Electronic Microscope (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). It was evidenced that the optimal process could produce a relatively complete and uniformed silane film compared to other cases. In addition, the results show that the Si–O–Ti covalent bonds were formed, which demonstrated that the preparation of the laminates through silane coupling agent is reliable.     

CaSO_4晶须补强增韧聚氨酯弹性体机理的研究

提高聚氨酯弹性体的力学性能是聚氨酯研究领域里普遍关心的课题之一,一般采用刚性粒子和纤维类无机填料增强聚氨酯弹性体,但上述填料在提高强度的同时,会导致韧性降低,空易造成脆性断裂,因此填料能否同时补强增韧聚氨酯弹性体具有重要的实际应用价值,晶须是一种单晶纤维状材料,其直径极小,几乎不存在任何缺陷,由于内在的完整性,高度有序的原子排列,使其强度接近晶体理论－－原子间价键的强度,晶须凭借微细的直径、较短的长度、极高的强度,成为一种新型补强增韧剂,目前晶须的复合基体多为陶瓷基、金属基和树脂基,有关复合基体多为陶瓷基、金属基和树脂基,有关复合聚氨酯弹性体的理论及应用研究报道很少,本文制备了具有较高强度和韧性的CaSO4晶须／聚氨酯弹性体复合材料,通过微观分析揭示了CaSO4晶须对聚氨酯弹性体补强增韧的机理,并对其影响因素进行了讨论。     

Mechanical Properties and Chemical Resistance of Short Tamarind Fiber/Unsaturated Polyester Composites: Influence of Fiber Modification and Fiber Content

In the present work, tamarind fibers were extracted from ripened fruits by the water retting process. Using these fibers as reinforcement and unsaturated polyester as matrix, composite samples were prepared by the hand lay-up technique. The effect of chemical surface treatments (alkali and silane) of tamarind fibers on the mechanical properties, chemical resistance, and interfacial bonding was studied. The mechanical properties of the composites with surface modified fibers were found to be higher than those with unmodified fibers. Morphological studies indicated improvement of interfacial bonding by alkali and silane coupling agent treatments of the fibers. The composites were found to be resistant to many chemicals.     

Characterization of sizing layers and buried polymer/sizing/substrate interfacial regions using a localized fluorescent probe

A novel technique is described to investigate buried polymer/sizing/substrate interfacial regions, in situ, by localizing a fluorescent probe molecule in the sizing layer. Epoxy functional silane coupling agent multilayers were deposited on glass microscope cover slips and doped with small levels of a fluorescently labeled silane coupling agent (FLSCA). The emission of the grafted FLSCA was dependent on the silane layer thickness, showing blue-shifted emission with decreasing thickness. The fluorescent results suggest that thinner layers were more tightly bound to the glass surface. The layers were also characterized by scanning electron microscopy, contact angle, and thermogravimetric analysis (TGA). When the FLSCA-doped silane layers were immersed in epoxy resin, a blue shift in emission occurred during resin cure, indicating the potential to study interfacial chemistry, in situ. Thicker silane layers exhibited smaller fluorescence shifts during cure, suggesting incomplete resin penetration into the thickest silane layers.     

The effect of compatibilizing and coupling agents on the mechanical properties of glass bead filled PP/PET blends

PP/PET blends (95/5) filled with 50% by weight of glass beads were prepared and studied at morphological and mechanical level, and compared with its analogous samples of glass bead-filled PP. The influence of a compatibilizing agent (maleic anhydride grafted polypropylene) and different silane coupling agents was analysed. It has been found that PET embeds glass bead surface independently on the silane coupling agent employed. Addition of MAPP in PP/PET blends leaded to tensile strength values similar to those of unfilled PP, but rupture takes place in a brittle manner.