环保型无机-有机聚氨酯超疏水性涂层的制备

<正>采用十三氟辛基三乙氧基硅烷(以下简称"F-硅烷")和γ-(甲基丙烯酰氧基)丙基三甲氧基硅烷(KH-570)改性nanoSiO2(纳米二氧化硅),制备出含双键的nano-SiO2粒子;然后将其喷射至含引发剂的端双键WPU(水性聚氨酯)涂层表面,通过加热固化反应,使nano-SiO2粒子接枝在WPU涂层表面,形成稳固粗糙结构的超疏水性涂层。研究结果表明:当m(F-硅烷):     

超疏水SiO2@OTES自清洁涂层的制备及性能

以纳米二氧化硅颗粒、正辛基三乙氧基硅烷(OTES)和硅烷偶联剂KH560为前驱体,采用溶胶凝胶法制备了超疏水SiO₂@OTES自清洁涂层。在酸性催化剂及有机溶剂中,OTES、KH560将纳米颗粒表面由亲水改性为疏水。探究了纳米SiO₂、OTES、KH560三种原材料含量对超疏水涂层润湿性能的影响。结果表明,当掺杂3.5 g纳米SiO₂,8%的OTES与2%的KH560时,涂层达到最佳疏水效果,其接触角为(154±1)°,滚动角为(3.3±0.5)°。采用SEM、FTIR红外光谱仪、X射线光电子能谱(XPS)对超疏水SiO₂@OTES材料的表面形貌与化学成分进行了表征。实验表明制备出的超疏水SiO₂@OTES自清洁涂层具有良好的自清洁防污、耐低温与耐磨性能,且将涂层回收重新制得的表面仍具有超疏水性。     

超疏水复合材料的制备及其在真石、质感涂料中的应用研究

采用正硅酸四乙酯(TEOS)以溶胶-凝胶法制备了粒径为100 nm的二氧化硅溶胶颗粒,以氨丙基三乙氧基硅烷(KH-550)、γ-二乙烯三胺丙基甲基二甲氧基硅烷(KH-603)作为纳米颗粒团聚体和附着力促进剂,使用十六烷基三甲氧基硅烷(HDTMS)对二氧化硅溶胶进行疏水处理得到改性溶胶颗粒,再以热塑性聚氨酯(TPU-95A)树脂为粘结剂,制备超疏水复合涂层。采用静态接触角(CA)、红外光谱(FT-IR)、粒径分布、透射电镜(TEM)对改性颗粒和涂层进行表征。结果表明:当KH-550与KH-603质量比为7∶3,TEOS与TPU-95A质量比为27.76∶1时,水滴在超疏水复合涂层的静态接触角高达152°,将此材料运用在真石、质感涂料上能够赋予涂层超疏水特性,使涂层具备耐沾污自清洁的功能。     

紫外光固化PUA/纳米SiO_2杂化涂层的制备与性能

采用γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH-570)对硅溶胶改性,将改性的硅溶胶与聚氨酯丙烯酸酯(PUA)低聚物共混,制备出聚碳酸酯(PC)用紫外光(UV)固化耐磨涂层。用红外光谱仪、热重分析仪、激光粒度仪、接触角测量仪对改性前后的纳米二氧化硅(SiO_2)进行了分析表征,并对制备的UV固化涂层的透光率、雾度、表面硬度和附着力进行了测试。结果表明:纳米SiO_2表面接枝上了KH-570,且亲水性降低。当KH-570用量为60%、改性纳米SiO_2用量为4%时,涂覆UV固化涂层的PC的耐磨性得到最佳改善,耐磨试验后,涂覆添加4%改性纳米SiO_2的UV固化涂层的PC较涂覆未添加纳米SiO_2的UV固化涂层的PC,透光率降低值从4.5%降至1.1%,雾度增加值从21.29%降至3.41%,PC表面涂层的铅笔硬度达到2H。     

纳米复合涂料

<正>201501061超疏水性纳米复合涂层表面结构分析及抗覆冰性能的研究[刊,英]/Davis,Alexander等//ACS Applied MaterialsInterfaces.2014,6(12).-9272~9279介绍了一种采用喷涂一种聚氨酯/二氧化硅/含氟丙烯酸超疏水纳米复合涂层来降低表面粗糙度的方法。通过调整组分配比、表面处理方式、喷涂参数等,在3个基材表面分别形成了不同粗糙度(8.7μm、2.7μm、1.6μm)的涂层,具有优异的超疏水性,并以     

基于疏水性TiO2纳米颗粒的悬浮液手印显现研究

利用偶联剂N-辛基三甲氧基硅烷(KH-318)对TiO₂纳米颗粒进行改性,制备表面改性的TiO₂纳米颗粒悬浮液,考察反应温度和反应时间对亲油化度的影响,使用光学显微镜考察在不同制备条件下改性疏水性TiO₂纳米颗粒悬浮液对手印显现效果的影响。结果表明,改性的TiO₂纳米颗粒悬浮液的疏水性在45℃反应2 h时最好,显现潜在手印的效果优异,可呈现出清晰的指纹三级特征。有机官能团通过Ti—O—Si化学键成功接枝到TiO₂纳米颗粒表面,且改性后的TiO₂纳米颗粒对潜在手印表面的脂类等物质具有良好的靶向吸附能力。改性的疏水性TiO₂纳米颗粒悬浮液的性质非常稳定,适合皮脂及油质等手印的高灵敏度显现,在化学及法庭科学领域具有较好的应用前景。     

纳米SiO_2表面化学改性研究

通过γ-(甲基丙烯酰氧)丙基三甲氧基硅烷与纳米SiO2表面的羟基发生化学反应,将KH-570化学键合在纳米SiO2表面,形成化学改性的纳米微粒MPS-SiO2。研究了硅烷偶联剂KH-570的用量、反应温度、反应时间、pH值、溶剂配比对纳米SiO2表面双键含量的影响,利用红外光谱、热失重对改性前、后的纳米SiO2进行了表征。结果表明,纳米SiO2表面成功地实现了化学改性。     

油田管道防垢的超疏水涂层的制备和性能研究

为解决管道结垢带来严重的经济损失和安全隐患,将超疏水涂层喷涂在管道内壁表面形成一层保护膜,以阻止流体与管壁的直接接触,研究以环氧树脂为基体,通过添加二氧化硅和氧化铝来构建表面微纳米结构,设计制备了EP-SiO₂/Al₂O₃超疏水涂层,通过调控2种无极纳米粒子的添加量优化涂层配方,并考察EP-SiO₂/Al₂O₃复合涂层的疏水和防垢性能。结果表明,当各投入5.1%SiO₂和5.1%Al₂O₃时涂层附着力为1级,同时接触角可达154.6°,复合涂层的垢结量明显降低,仅为同等状态下环氧涂层的16.5%。为减少油田管道的结垢和腐蚀,提高油田的经济效益和安全效益提供可行途径。     

防紫外线超疏水织物涂层构筑及性能

以羟基氟硅油、季戊四醇三丙烯酸酯(PETA)为原料,制备了含双键的聚氨酯,在整理液中添加紫外线吸收剂(UVA400)和纳米二氧化硅颗粒,以提高涂层的紫外线防护效果和表面粗糙度,通过紫外光引发双键自由基聚合构筑防紫外超疏水织物涂层,并对材料进行了FTIR、SEM、疏水性及紫外线防护性能测试。结果表明:羟基氟硅油和PETA引入到了聚氨酯分子链中;织物表面具有微纳米状凸起,形成了粗糙的表面涂层。当整理液固体组分中w(SiO2)=15%,w(UVA400)=1.5%时,涂层织物的接触角为154?,滚动角为9?,紫外线防护系数(UPF)为72,紫外线A(UV-A)波段的透过率为2.96%,具有超疏水和紫外线防护性能;涂层织物经120h加速老化实验后,接触角为155?,UPF为117,UV-A波段的透过率为2.68%,具有良好的耐久性。     

改性SiO2/聚硅氧烷无氟超疏水涂层的制备及性能

为了提高基体材料的防污能力,在基体表面制备了一种无氟超疏水复合涂层。首先,使用十六烷基三甲氧基硅烷(HDTMS)对二氧化硅(SiO_2)微纳米颗粒进行疏水改性,其次,将改性后的SiO_2颗粒与有机硅烷混合,利用硅烷的水解、聚合在基体材料的表面得到一层稳定的无氟超疏水复合涂层。采用FTIR、TGA、SEM、AFM和接触角测量仪对涂层的化学组成、表面微观结构和疏水性能进行表征。结果表明:复合涂层表面具有微纳米尺度的粗糙结构,并具有优异的自清洁性和耐磨损性;未磨损前接触角达151°,磨损100周次后接触角进一步提高至161°。     

改性纳米SiO2/聚氨酯-含氟丙烯酸酯无皂乳液合成及其胶膜性能表征

引言水性聚氨酯相对溶剂型聚氨酯具有不燃、气味小、不污染环境等优点[1-2],从而广泛用于涂料[3]、胶黏剂[4]、油墨[5]等领域。目前,常用于软包装领域的薄膜主要是表面能很低的非极性膜,而水性聚氨酯胶黏剂具有较高的表面自由能,对非极性膜的润湿性差,因此需要降低水性聚氨酯的表面张力,达到润湿非极性膜的目的。     

Preparation of antireflection coatings with novel cationic–nonionic PU‐SiO2 core–shell particle dispersions

A novel polyurethane (PU)‐SiO₂ core–shell particle dispersion was prepared by an acid‐catalyzed sol–gel process using cationic–nonionic PU particle as template. Results of average sizes, polydispersity index, and transmission electron microscope indicated that tetramethylorthosilicate were first diffused to the surface of PU particles, then occurring hydrolysis–condensation reaction to form core–shell particles. Antireflection coating formulation was prepared by as‐prepared core–shell particle dispersion and SiO₂ sol binder. After dip‐coating in the formulation, antireflection coating was formed on glass surface by calcination. Scanning electron microscopy images showed that pores had been formed inside coating after removing PU template particles, and the coating surface could be almost fully closed. In addition, ultraviolet–visible spectrophotometer analysis showed that the maximum transmittance of antireflection glasses can be as high as 98.6% at 548 nm. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45762.     

Formation of deagglomerated PLGA particles and PLGA-coated ultra fine powders by rapid expansion of supercritical solution with ethanol cosolvent

Rapid expansion of supercritical solution (RESS) was used for preparing polymer particles and polymer coating of ultra fine powders. The polymer of pharmaceutical interest was Poly(lactic-co-glycolic acid) (PLGA with PLA: PGA ratio of 85: 15 and MW of 50,000–75,000) and the simulated core particles were 1.4-μm SiO₂ and 70-nm TiO₂ particles. The supercritical solution was prepared by dissolving PLGA in supercritical carbon dioxide with ethanol as a cosolvent. Supercritical solution of CO₂-PLGA was sprayed through capillary nozzles to ambient conditions, resulting in formation of submicron PLGA particles. Similarly, rapid expansion of supercritical solution of CO₂-PLGA suspended with the core particles could provide solvent evaporation and deposition of submicron PLGA particles on the surface of the core particles, resulting in the formation of coating films on dispersed particles of SiO₂ and agglomerates of TiO₂. The influences of the core particle size, spray nozzle diameter as well as powder-to-polymer weight ratio were also investigated and discussed with respect to the coating performance.     

Supercritical CO2 Spray Drying of Ethyl Cellulose (EC) for Preparing Microparticles

Even though common spray drying has been widely used for drying food and related products, the effect of drying conditions of supercritical CO₂ spray drying on the particle sizes of dried products has not been well studied. The objective of this study was to study the effect of drying conditions and design parameters on the particle sizes of biomaterials dried with supercritical CO₂ spray drying. The ethyl cellulose (EC) microparticles were prepared with supercritical CO₂ as the dry medium using an experimental spray-drying apparatus. This research studied the influences of spray nozzle diameter, mass ratio of gas to liquid, solution concentration, temperature, and pressure on the physical characteristics of ethyl cellulose microparticles. The results indicated that the average size of the dried particles ranged from 1.07 to 9.84 µm. The spray nozzle with 8-mm diameter produced smaller microparticles with narrower distribution than the 4-mm spray nozzle. The average particle size increased with the increase of the ratio of gas to liquid. Also, the average size and distribution of the microparticles increased with the rise of temperature and solution concentration but decreased with the increase of pressure.     

Surface and mechanical properties of an organic-inorganic super- hydrophobic coating using modified nano-SiO2 and mixing polyurethane emulsion as raw materials

A series of organic-inorganic super-hydrophobic coatings were prepared using nano-SiO₂ particles modified by fluorine and silicone coupling agents, and a mixing polyurethane emulsion as main raw materials. The mixing polyurethane emulsion was consisted of the polyurethane emulsion end-terminated by double bond (WPUD) and polyurethane emulsion modified by silicone (WPUS). The influence of content of modified nano-SiO₂ particles and the weight ratio of WPUS to WPUD on microstructure and hydrophobicity of the coating surface were studied. The morphologies of coating surface were examined using SEM and AFM, hydrophobicity of the coating was researched by examining static water contact angle and so on. It was found that modified nano-SiO₂ particle was an indispensable factor during the preparation of super-hydrophobic coating. The roughness and hydrophobicity of the coating surface were enhanced obviously with an increase of the content of the modified nano-SiO₂ particles. When the content of the modified nano-SiO₂ particles increased up to 1.5%, the surface of coating possessed good super-hydrophobicity, and static water contact angle reached 169.1°. It was also noticed that the weight ratio of WPUS to WPUD in the base layer has also an important influence on the hydrophobicity and mechanical property of coating surface. With an increase of the ratio of WPUS to WPUD the hydrophobicity of the coating was enhanced, the tensile strength and peel strength reduced, but the elongation at break increased. When the weight ratio of WPUS to WPUD reaches up to 9/100, the static water contact angle reaches the maximum value of 169.1°.     

Application of EIS and salt spray tests for investigation of the anticorrosion properties of polyurethane-based nanocomposites containing Cr2O3 nanoparticles modified with 3-amino propyl trimethoxy silane

The Cr₂O₃ nanoparticles were modified with 3-amino propyl trimethoxy silane in order to obtain proper dispersion and increment compatibility with the polyurethane coating matrix. The nanocomposites prepared were applied on the St-37 steel substrates. The existence of 3-amino propyl trimethoxy silane on the surface of the nanoparticles was investigated by Fourier transform infrared (FTIR) spectroscopy and thermal gravimetric analysis (TGA). Dispersion of the surface modified particles in the polyurethane coating matrix was studied by a field emission-scanning electron microscope (FE-SEM). The electrochemical impedance spectroscopy (EIS) and salt spray tests were employed in order to evaluate the corrosion resistance of the polyurethane coatings. Polarization test was done in order to investigate the corrosion inhibition properties of the Cr₂O₃ nanoparticle on the steel surface in 3.5 wt.% NaCl solution. The adhesion strengths of the coatings were evaluated by pull-off adhesion tester before and after 120 days immersion in 3.5 wt.% NaCl solution. FT-IR and TGA analyses revealed that surface modification of the nanoparticles with 0.43 silane/5 g pigment resulted in the greatest amount of silane grafting on the surface of particles. Results obtained from FE-SEM analysis showed that the surface modified nanoparticles dispersed in the coating matrix properly. Results obtained from EIS and salt spray analyses revealed that the surface modified particles enhanced the corrosion protection performance of the polyurethane coating considerably. The improvement was more pronounced for the coating reinforced with 0.43 g silane/5 g pigment. Moreover, the adhesion loss decreased in the presence of surface modified nanoparticles with 0.43 silane/5 g pigment.     

Preparation and properties of fluorinated silicon two‐component polyurethane hydrophobic coatings

A polyurethane (PU) hydrophobic coating was prepared by the two‐component method, polycarbonate diol and isophorone diisocyanate becoming a two‐phase composition. The PU films with hydrophobic surface were prepared by establishing a rough structure on the surface of silica (SiO₂) modified with silane coupling agents (γ‐(2,3‐epoxypropoxy)propytrimethoxysilane (KH560) and (heptadecafluoro‐1,1,2,2‐tetradecyl)trimethoxysilane (FAS)). First, the surface of SiO₂ was covered by a layer of hydrophobic methyl and fluorocarbon (C–F) groups. Then, the SiO₂ and modified SiO₂ were obtained by the introduction of KH560 and FAS with the silanol reaction by ultrasonic stirring. The effect of SiO₂ and modified SiO₂ on the structure and hydrophobic properties of PU was investigated by a series of test instruments. The results showed that the introduction of SiO₂ and modified SiO₂ was beneficial for increasing the roughness of the PU coating surface; the roughness of FAS/SiO₂‐PU could reach up to 14.790 nm, four times better than pure PU. A hydrophobic modified PU coating with water contact angle 123° was fabricated by using the hydrophobic C–F group FAS as a low surface energy material and establishing a micro rough structure on the surface of PU. Moreover, PU modified with KH560 and FAS can reduce the glass transition temperature (T_g) of soft segments, resulting in improvement of micro‐phase separation. © 2020 Society of Chemical Industry     

Batch production of micron size particles from poly(ethylene glycol) using supercritical CO2 as a processing solvent

The major advantage of using supercritical carbon dioxide (CO₂) as a solvent in polymer processing is an enhancement in the free volume of a polymer due to dissolved CO₂, which causes a considerable reduction in the viscosity. This allows spraying the polymer melt at low temperatures to produce micron size particles. We have used supercritical CO₂ as a solvent for the generation of particles from poly(ethylene glycol) (PEG) of different molecular weights. Since PEG is a hydrophilic compound, it is a most commonly used polymer for encapsulating a drug. PEG particles with different properties may allow keeping a good control over the release of the drug. It has been possible to produce particles with different size, size distribution, porosity and shape by varying various process parameters such as molecular weight, temperature, pressure and nozzle diameter. A flow and a solidification model have been applied in order to have a theoretical insight into the role of different parameters.     

Characterization of bimetallic surface structures of highly active Rh-Sn/SiO2 catalysts for NO-H2 reaction by EXAFS

Rh-Sn/SiO₂ catalysts prepared by the reaction of (CH₃)₄Sn with Rh metal particles supported on SiO₂ have remarkably high activities for NO-H₂ reaction and NO dissociation. The bimetallic surface structure of Rh-Sn/SiO₂ composed of an isolated Rh atom surrounded by six Sn atoms, is presented by Rh K-edge and Sn K-edge EXAFS, FT-IR, TEM and CO adsorption.     

Novel surfactant-free waterborne acrylic-silicone modified alkyd hybrid resin coatings containing nano-silica for the corrosion protection of carbon steel

We report a novel waterborne acrylic-silicone modified alkyd nanocomposite latex containing nano-silica prepared by the surfactant-free miniemulsion polymerization. The influences of γ-methacryloxy-propyltrimethoxysilane- (MPS-) modified nano-silica particle contents to the thermal, mechanical and anti-corrosion performance of hybrid latex coatings were studied. The results revealed that the incorporation of nano-silica particles into latex films could directly increase the thermal stability and mechanical properties. Electrochemical corrosion studies revealed that these nanocomposite coatings exhibited superior corrosion resistance performance (inhibition efficiency 99.36% and corrosion rate 1.09 × 10 ^?3 mm per year) than that of the control system (without SiO₂ NPs).