一种大分子偶联剂的制备与应用研究

采用溶液聚合法合成了苯乙烯(St)-马来酸酐(MAH)-丙烯酸丁酯(BA)三元共聚物P(St-BA-MAH),再与γ-氨基丙基三乙氧基硅烷(KH-550)反应制备了一种新型大分子偶联剂(NDCZ)。用红外光谱(IR)、核磁共振(1 H-NMR)和凝胶渗透色谱(GPC)对产物结构和分子量及其分布进行了表征。将合成的NDCZ对滑石粉表面改性,用于制备滑石粉增强聚丙烯复合材料,采用接触角、力学性能测试研究了滑石粉改性效果及NDCZ对复合材料力学性能的影响。结果表明:滑石粉经NDCZ改性后较改性前表面接触角从42.2°提高到101.3°;添加经NDCZ改性滑石粉的聚丙烯复合材料与添加未改性滑石粉(20份)对照样相比,复合材料拉伸强度提高了45.2%,弹性模量提高了56.7%,断裂伸长率提高了183.5%,冲击强度提高了62.5%。     

硅烷偶联剂IPTS改性纳米ZnO的制备及性能研究

以纳米ZnO、乙醇酸乙酯、异氰酸丙基三乙氧基硅烷(IPTS)为原料,通过脱水缩合制备了一种新型的硅烷偶联剂改性ZnO纳米粒子(I-ZnO)。采用FT-IR、XRD、TG、粒径分析、抑菌圈法等手段表征改性前后纳米ZnO的结构与性能,并探究了不同用量的硅烷偶联剂IPTS对纳米ZnO分散效果的影响。结果表明,I-ZnO(3)(IPTS用量为纳米ZnO用量的25%)样品的分散效果最好,ZnO纳米粒子团聚体的平均粒径最小,为396.9nm,粒径分布系数为0.081。I-ZnO(3)表面有IPTS最大包覆量为4.66%,同时与未改性纳米ZnO相比,I-ZnO(3)具有更优良的抗菌性能。     

疏水性KH550-TiO2@PDMS@PU海绵的简单制备及油水分离性能

在钢铁产品的生产流程中,不可避免地产生含油废水,若不加以处理,会对生态环境造成严重的破坏,进而威胁人类健康。以TiO₂纳米颗粒,3-氨基丙基三乙氧基硅烷(KH550)与聚二甲基硅氧烷(PDMS)为主要化学试剂,通过简单的一步浸渍法,制备了一种疏水亲油的KH550-TiO₂@PDMS@PU改性海绵。低表面能PDMS层与KH550改性的TiO₂微米颗粒形成的粗糙结构,能显著提高海绵的疏水性能,接触角为(147.25±1.44)°。改性后的海绵经过胶粘、挤压、酸碱、超声等复杂条件下仍能保持稳定的疏水性和耐久性。改性海绵的吸油能力高达自身质量的20～25倍,可通过吸附-挤压循环的方式进行吸油。优秀的油水分离性能表明,KH550-TiO₂@PDMS@PU海绵具有无毒、易制备、稳定、疏水等优点,在钢铁行业具有广阔的应用前景。     

二乙氧基硅烷与三乙氧基硅烷共聚物的合成及表征

利用盐酸为催化剂,以二甲基乙氧基硅烷、二苯基乙氧基硅烷、γ-(2,3-环氧丙氧)丙基三甲氧基硅烷及水进行水解缩聚反应,制备了具有反应活性的有机-无机杂化有机硅树脂共聚物。通过正交实验研究了催化剂浓度、原料配比、温度及水对树脂产率的影响,得出适宜的合成工艺条件为酸浓度为0.05mol/L、原料配比为1.5∶2.5∶6、温度为70℃、水量为0.1mol。采用红外光谱、核磁对最优配比产物结构进行了表征,表明树脂中具有可反应性基团,其主链为硅氧链。采用GPC分析,数均分子量为43040,分散系数为2.3,分布较宽。     

Ag掺杂APS改性的TiO2颗粒的制备及其光催化降解作用

为提高Ag/TiO2纳米颗粒的光催化降解作用,采用聚合凝胶工艺路线,以钛酸四丁酯为前驱体,硝酸银为银源,通过向反应体系引入鳌合剂醋酸、表面改性剂γ-氨丙基三乙氧基硅烷(APS)以及还原剂甲醛等添加剂,制备出TiO2粉体及Ag/TiO2纳米复合粉体。利用FT-IR、XRD、TG-DTA、TEM和UV-Vis-NIR等手段对样品进行表征。结果表明,经γ-氨丙基三乙氧基硅烷改性的TiO2颗粒掺Ag后分散性得到改善,粒径约1 nm的Ag颗粒较均匀地分布在10～15 nm TiO2颗粒上;可见光的利用和锐钛矿热稳定性都得到提高;Ag/TiO2纳米颗粒在光照下对甲基橙具有良好的光催化降解效果。     

低温固化硅树脂的制备及其防腐蚀涂层性能研究

以硅酸乙酯(TEOS)、乙烯基三乙氧基硅烷(VTES)和二甲基二甲氧基硅烷(DMDMS)为硅烷单体,以柠檬酸为催化剂,采用溶胶-凝胶法制备乙烯基甲基硅树脂,并添加固化剂γ-氨丙基三乙氧基硅烷(APTES)使制备的硅树脂可以在较低温度(50℃)下固化。采用红外光谱(FT-IR)对比硅树脂固化前后的结构变化;通过接触角、吸水率、电化学阻抗谱(EIS)测试了不同n(R)/n(Si)、n(Si—OC_nH_(2n+1))/n(H_2O)、pH以及固化剂用量对硅树脂涂层耐水性和防腐蚀性能的影响。结果表明:当n(R)/n(Si)=1.4/1、n(Si—OC_nH_(2n+1))/n(H_2O)=0.2/0.2、pH=2.6、固化剂用量为4%(质量分数)时,涂层具有较好的性能。     

乙烯基POSS的合成及POSS/PMMA纳米复合材料的制备

利用乙烯基三甲氧基硅烷缩合水解制备八聚乙烯基笼型倍半硅氧烷(OvPOSS),然后将其与γ-巯丙基三乙氧基硅烷(KH580)采用巯基-烯点击化学反应制备带有部分乙烯基和烷氧基的POSS,用红外光谱、核磁共振、凝胶渗透色谱、飞行质谱等手段对其结构进行表征分析。通过自由基聚合将POSS引入聚甲基丙烯酸甲酯(PMMA)中,制备新型纳米复合材料EV-POSS/PMMA,利用X射线衍射、扫描电镜、热重分析探讨了OvPOSS、EV-POSS在PMMA中的形态特征、分散性、透光率及材料的热稳定性能。结果显示,OvPOSS在PMMA中结晶程度大,分散性差,导致其对PMMA的热稳定的影响不明显;EV-POSS则呈现良好的分散性,包覆于PMMA中,对PMMA的热稳定性提高显著,同时对于PMMA的透光率影响较小。     

改性碱式次氯酸镁/聚乙烯醇抗菌复合膜的制备及性能

为解决食品、药品等易被细菌污染及其包装造成环境污染问题,通过γ-氨丙基三乙氧基硅烷(KH-550)表面改性碱式次氯酸镁(BMH),并将其与聚乙烯醇(PVA)进行复合,制备改性碱式次氯酸镁/聚乙烯醇抗菌复合膜(改性BMH/PVA抗菌复合膜).通过SEM、接触角分析、抑菌圈实验和FTIR,证明了BMH的有机改性的有效性.通...     

γ-氯丙基三乙氧基硅烷对SiO_2-AgCl复合溶胶凝胶薄膜性能的影响

以正硅酸乙酯(TEOS)为前驱体经γ-氯丙基三乙氧基硅烷(CPTES)改性后制备硅溶胶,与以醇盐硝酸银(AgNO3)为前驱体制备的AgCl溶胶共混后形成复合溶胶,采用浸渍提拉法涂覆于PET基片表面形成SiO2-AgCl复合薄膜,采用SEM、FTIR、机械折叠、接触角测试、烘干质量法、贴膜法研究硅烷偶联剂含量对溶胶-凝胶成膜过程、成膜特性等的影响。结果表明,当摩尔比n(CPTES)∶n(TEOS)=1时可获得表面光滑膜厚均匀,具有良好膜基结合力、疏水性能、耐水性能及抗菌性能的SiO2-AgCl复合薄膜。     

溶胶-凝胶法制备(Ba,Sr)TiO3薄膜的新技术路线研究

碳酸钡和碳酸锶是无机盐化工基础原料,钡、锶的醇盐或醋酸盐都需通过其碳酸盐制备而得,本文探索了一种有利于降低成本的新实验路线和更为原子经济的新工艺。直接采用碳酸盐为原料,采用 sol gel法制备了 Ba0.8 Sr0.2 TiO3 (BST)薄膜;并利用 X射线衍射(XRD)、原子力显微镜(AFM)和X射线光电子能谱分析(XPS)等对 BST 薄膜的晶体结构和表面形貌及化学组态进行了分析。结果表明,利用碳酸盐代替醋酸盐为原料,采用 sol gel 技术制备 BST 铁电薄膜,能制备出均匀清澈的溶胶;所制备的 BST薄膜均匀致密,几乎为全钙钛矿结构。化学组态分析也表明所制备的薄膜中的钡、锶、钛、氧 4 种元素都以钙钛矿相结构中各元素相应的化学态存在。     

A facile and green approach to prepare monodispersion nanonickel nanofluids

This paper first develops a novel approach to prepare solvent-free nanonickel (Ni) nanofluids via hydrogen bonding between poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) and 3-(Trimethoxysilyl)-1-propanethiol-modified Ni powder with average diameter of 80?nm to solve the problem of nanoparticles agglomerating due to the anisotropic dipolar attraction. It is interestingly found that Ni nanofluid is solid at room temperature while it undergoes solid–liquid transition without solvent at 50.7°C. The content of Ni is up to 12.1?wt%. The average diameter of core-shell structure of Ni nanofluids is 182?nm without agglomerations. It is worth noting that incorporation of Ni powder can elevate remarkably initial decomposition temperature of block copolymer due to high dispersity of Ni powder after modification. In addition, the viscosity of Ni nanofluids is found to be less than 10?Pa?·?s at 100°C, which is between that of water and honey, 0.001 and 10?Pa?·?s, respectively, at 20°C. More importantly, the Ni nanofluids exhibit excellent dispersion in water and other organic solvents for 2 months due to amphiphilic properties of the modifier molecule. These unique properties of Ni nanofluids may offer new scientific and technical opportunities for application of Ni powder in the form of liquid-like status.     

A novel approach to prepare solvent-free cerium dioxide nanofluids

This paper develops a novel approach to prepare solvent-free cerium dioxide (CeO₂) nanofluids through N,N-didecyl-N-methyl-N-(3-trimethoxysilylpropyl) ammonium chloride covalently grafted on the surface of CeO₂ nanoparticles as core, and then poly(ethylene glycol) 4-nonylpheny 13-sulfopropyl ether sodium salt was grafted on the surface of CeO₂ nanoparticles through ion exchange reaction. It is obviously observed that CeO₂ nanofluids exhibited a solid state at room temperature, whereas they behave as liquid-like when being heated to above 45°C. To detect the properties of CeO₂ nanofluids, the morphology, thermal stability, dispersibility, and rheological behavior of CeO₂ nanofluids are mainly investigated. It is found that CeO₂ nanofluids can flow without solvent existence. Meantime, it shows good dispersion and stability in water and other organic solvents for weeks due to amphiphilic properties of the modifier molecules.     

One-step approach to prepare magnetic iron oxide/reduced graphene oxide nanohybrid for efficient organic and inorganic pollutants removal

An environmentally friendly effective technique was demonstrated to prepare iron oxide/reduced graphene oxide nanohybrid (IO/RGO) at room temperature by using banana peel ash aqueous extract as the base source and Colocasia esculenta leaves aqueous extract as the reducing agent. The nanohybrid was characterized by Fourier transform infrared spectroscopy, X-ray diffractometry, transmission electron microscopy, vibrating sample magnetometry, Raman spectroscopy and thermal studies. The results indicated the decoration of superparamagnetic IO nanoparticles on the surface of the RGO. Both organic and inorganic pollutants were effectively removed from the contaminated water (for Pb²⁺ and Cd²⁺ within 10 min, whereas for tetrabromobisphenol A within 30 min) by IO/RGO. The study revealed that adsorption followed pseudo-second order kinetics and isotherms were well described by the Langmuir model in all the cases. The thermodynamics parameters (ΔG°, ΔS° and ΔH°) were calculated from the temperature dependent isotherms and indicated that the adsorptions were endothermic and spontaneous.     

A new approach to triaxial residual stress evaluation by the hole drilling method

A new analysis technique is introduced to resolve the triaxial residual stress profiles from measurements using the conventional strain gauges for the hole drilling or ring core method extended with a displacement transducer to measure the out of plane displacement. The new technique uses an inverse formulation with wavelets.     

Template-free mechanochemical route to prepare crystalline and electroactive polydiphenylamine nanostructures

A facile and sustainable mechanochemical route for the synthesis of undoped polydiphenylamine (PDPA) and inorganic acid doped nanostructures are reported. Field emission scanning electron microscopic (FESEM) images highlighted the formation of distinctly different nanostructures for each of the inorganic acid doped PDPA. Elemental analysis carried out for the polymers revealed the presence of more repeating units in their backbone. The X-ray diffraction (XRD) results of the as-prepared PDPA nanostructures indicated the high degree of crystallinity ever reported for PDPA. Spectroscopic profile of the polymers showed that the prepared PDPA is in a doped conducting form. Electrochemical studies performed for the polymeric particles ascertained the redox behaviour and the good electrochemical activity of obtained PDPA samples. The probable mechanistic aspect behind the formation of PDPA nanostructures through this simple and efficient route is discussed.     

A simple lithographic method employing 172 nm vacuum ultraviolet light to prepare positive- and negative-tone poly(methyl methacrylate) patterns

We successfully prepared both positive- and negative-tone patterns by applying poly(methyl methacrylate) (PMMA) as a photoresist. A positive-pattern was prepared by lithography through a photomask using 172 nm vacuum ultraviolet (VUV) light under the pressure of 10³ Pa. A negative-pattern was prepared using the same VUV light under the reduced pressure of 10 Pa, followed by rinsing with toluene solution. At 10³ Pa, the irradiated PMMA was effectively decomposed and eliminated. On the other hand, at 10 Pa, the irradiated PMMA became cured and resistant to etching. We subsequently utilized these positive- and negative-tone patterns as templates on indium–tin-oxide surfaces to electrodeposit copper microstructures with 10 µm lines and spaces.     

A microcontroller-based approach to monitoring pneumatic actuators

This paper presents the development of a microcontroller-based process monitoring system that is capable of being embedded within high speed automated assembly systems. A generic architecture is presented to fully utilise the communication, data acquisition and signal processing attributes of a current generation microcontroller. The efficacy of this approach is illustrated by the development of an autonomous method in which the system acquires and analyses transient data related to the operation of a linear actuator. The performance of this system clearly identifies the potential of microcontroller based solutions as very powerful yet affordable real-time quality management tools. The low costs associated with the implementation offer the prospect of affordable integrated quality management to a wide range of industries.     

A new method to prepare high-surface-area N-TiO2/activated carbon

A new method, combining impregnation and vapor-hydrolysis, was developed to prepare hybrid photocatalyst: nitrogen doped TiO₂ coated activated carbon (N-TiO₂/AC). The activated carbon (AC) was impregnated into titanium tetraethoxide/urea/methanol solution, and then the impregnated AC powder was kept in water vapor at 90 °C for 3 h for hydrolysis. Then it was calcinated to fabricate N-TiO₂/AC. Transmission electron microscopy (TEM) results showed that the nitrogen doped TiO₂ (N-TiO₂) in the as-synthesized hybrid was anatase TiO₂ powder with 10-20 nm in grain size, and the bandgap was about 3.08 eV. Moreover, the hybrid photocatalyst (8 wt.% N-TiO₂) had high specific surface area that was up to 1321 m²/g. The hybrid photocatalyst is expected to have high photocatalytic performance with visible irradiation.