Corrosion resistance and infrared emissivity properties of EPDM (EPDM-g-MAH) film on low infrared emissivity PU/Cu coating

In order to improve the corrosion resistance of low infrared emissivity polyurethane (PU)/Cu coating, ethylene-propylene-diene monomer (EPDM) and maleic anhydride grafted EPDM (EPDM-g-MAH) were deposited on PU/Cu coating by spin coating, respectively. The ability of EPDM and EPDM-g-MAH to serve as corrosion protective films for PU/Cu coating was examined by evolved emissivity immersion test and potentiodynamic polarization measurements in 3.5% NaCl solution. And the chemical composition and surface morphology of PU/Cu coating before and after corrosion were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that all of the coated samples present a better corrosion resistance than bare PU/Cu coating due to indissolubility of Cu by aggressive ions, and the effect of EPDM-g-MAH is better than that of EPDM.     

不同颜色色浆对氟树脂/铝低红外发射率涂层的影响

研究了大红、深黄、水紫、黑色4种颜色色浆对氟树脂/铝低红外发射率涂层光泽、附着力、硬度、粗糙度、耐冲击性、色差、红外发射率、耐腐蚀性等性能的影响。研究结果显示:深黄色色浆涂层的发射率最低,约为0.1;不同色浆对氟树脂涂层色差明度影响不同,相对于其他色浆,水紫能够使涂层偏暗;大红、深黄、水紫色浆的涂层硬度均为6H;加深黄色浆的涂层附着力最好,其次是大红色浆和水紫色浆;深黄色浆对涂层的耐冲击性影响最大,其次是大红色浆和水紫色浆;相对于大红、深黄、黑色色浆,水紫色浆涂层具有最低的粗糙度,表面比较光滑;水紫色浆和深黄色浆的红外波峰比较持平,有利于减小表面发射率;水紫色浆氟树脂涂层的耐腐蚀性能最好。耐盐水腐蚀测试后4种涂层均没有明显失光,水紫涂层没有发生明显变色,深黄和黑色涂层起泡密度较低。水紫色浆因其粒径均匀细小,在氟树脂涂料中易分散,与氟树脂相容性好,因此具有相对较优的综合性能。     

Effects of size, shape and floatage of Cu particles on the low infrared emissivity coatings

Low infrared emissivity coating was prepared by the copper (Cu) particles and ethylene–propylene–diene monomer (EPDM) binder. The effect of size, shape and floatage of Cu particles on infrared emissivity of the coatings was systematically investigated. The results indicated that the optimized Cu particles with the minimum coating emissivity are several micron-sized, flaky and high-leafing, exhibiting 0.78, 0.72 and 0.10 emissivity value, respectively. The formation of low infrared emissivity coatings depends strongly on the floatage of Cu particles, not the size or shape, and the results obtained by leafing aluminum (Al) and bismuth oxide (Bi₂O₃) pigment are in good agreement with this standpoint. A theoretical model was proposed to account for the mechanism, which indicated that the low porosity of the coatings with leafing pigments plays an important role in the formation of low emissivity coatings.     

Preparation of Tung Oil-Loaded PU/PANI Microcapsules and Synergetic Anti-Corrosion Properties of Self-Healing Epoxy Coatings

Tung oil is used as a catalyst-free repair agent. Tung oil-loaded polyurethane (PU) microcapsules are prepared by interfacial polymerization in a SiO₂-stabilized Pickering emulsion system, polyaniline (PANI) is deposited in situ on the PU microcapsule surface, and tung oil-loaded PU/PANI double-layer shell microcapsules are obtained. Synthesized PU/PANI microcapsules showed the characteristic dark-green color of conductive PANI. The average particle size is 31.1 ± 8.1 µm and the core content is 45.1 ± 4.3 wt%. The microcapsules have a good thermal stability, and the chemical structure of the PU/PANI wall and tung oil core is confirmed by Fourier transform infrared analysis. Self-healing anti-corrosion coatings are prepared by adding 10 wt% microcapsules into epoxy resin. The corrosion resistance properties of the self-healing coating are evaluated by immersing scratched coatings in 10 wt% NaCl solution for 15 days. The self-healing coating with 10 wt% tung oil-loaded PU/PANI microcapsules have the best anti-corrosion property, and slight corrosion do not occur until 15 days after immersion in salt solution. The self-healing and anti-corrosion mechanism are revealed. The tung oil core and the PANI wall of microcapsules contributed synergistically to the excellent self-healing and anti-corrosion properties of the coating through the formation of self-healing films and passivation layers.     

The lifetime assessment of low infrared emissivity composite coatings in chloride environments

The microstructural-electrochemical model is employed to predict the lifetime of low infrared emissivity composite coatings in chloride environments. Electrochemical data collected in 3.5 wt.% NaCl solution is presented for the low infrared emissivity coating, and these values are used as inputs for a mechanistic-based corrosion model which yields the salt spray life of the coating. To check the calculated results, the model predictions were compared with the results of salt spray tests. The current work showed that the model was able to predict lifetime of low infrared emissivity coating under salt spray, but tended to under-predict lifetime at short times and over-predict at long times. Under-prediction may be associated with corrosion protection of metallic pigment particles by polymer. Over-prediction by the model at longer exposure times may be associated with the fact that an influence of porosity is not included as a part of this simple model.     

The lifetime assessment of low infrared emissivity composite coatings in chloride environments

The microstructural-electrochemical model is employed to predict the lifetime of low infrared emissivity composite coatings in chloride environments. Electrochemical data collected in 3.5 wt.% NaCl solution is presented for the low infrared emissivity coating, and these values are used as inputs for a mechanistic-based corrosion model which yields the salt spray life of the coating. To check the calculated results, the model predictions were compared with the results of salt spray tests. The current work showed that the model was able to predict lifetime of low infrared emissivity coating under salt spray, but tended to under-predict lifetime at short times and over-predict at long times. Under-prediction may be associated with corrosion protection of metallic pigment particles by polymer. Over-prediction by the model at longer exposure times may be associated with the fact that an influence of porosity is not included as a part of this simple model.     

热红外伪装涂料的制备研究

以自制的水性粘合剂制备了一种热红外伪装涂料,刷涂于载体上,制得热红外伪装涂层.研究了载体的种类和涂层增质量率对涂层红外发射率的影响,并研究了涂层增质量率对涂层透湿、耐磨和耐有机溶剂等性能的影响.研究结果表明:选用涤纶布为涂层载体,当涂层增质量率为30％时,制备的织物涂层具有良好的透湿性、耐摩擦性和耐有机溶剂腐蚀性,此时涂层的红外发射率为0.61,满足作为热红外伪装织物的基本要求.     

PBS/天然虎杖提取物复合材料的界面作用及其性能

将天然虎杖提取物(PCSZ)与可生物降解材料聚丁二酸丁二酯(PBS)复合,为了提高两者之间的相容性,采用硅烷偶联剂KH–550对提取物进行预处理,通过分子模拟阐明了PCSZ,KH–550与PBS间的界面作用,探讨了界面作用对PBS/PCSZ,PBS/KH–550改性PCSZ(PCSZ+K)复合材料性能的影响。结果表明,PCSZ只与PBS进行了共混,偶联剂对提取物进行预处理时,其乙氧基发生了水解。分子模拟表明提取物与PBS能够形成C=O…H—O;而偶联剂与提取物之间首先形成H—O…H—O,再通过偶联剂有机官能团—NH2与PBS形成静电吸附,同时未与偶联剂作用的提取物仍可与PBS形成C=O…H—O,增强了界面结合强度。PBS/PCSZ+K复合材料的混合能和Huggins参数相对于PBS/PCSZ复合材料更低,其相容性更好,使得PBS/PCSZ+K复合材料的热稳定性、拉伸性能、疏水性均较PBS/PCSZ复合材料有所提高。     

铝粉的表面有机化改性及其对环氧基复合材料介电性能的影响

通过溶胶-凝胶法制备了铝粉（Al）的二氧化硅（SiO2）包覆粒子SiO2@Al,并用硅烷偶联剂KH550进行有机化改性得到SiO2@Al-KH550。通过FT-IT表征其包覆与处理效果,通过缓蚀效率实验与静态水接触角实验验证其耐腐性与疏水性,以及SEM测试分析其微观结构。利用浇注法制备SiO2@Al-KH550/环氧树脂复合材料,介电性能测试表明当SiO2@Al- KH550含量为35%wt时,介电常数达到30,为纯环氧树脂的6倍,介电损耗0.065,为制备金属粒子/环氧树脂介电复合材料提供了新的思路。     

Preparation and characterization of a new low infrared-emissivity coating based on modified aluminum

A low infrared-emissivity coating was prepared using modified Al powder and polyurethane as metallic pigment and adhesive. Al powder was coated with polyethylene wax by the flux-capping method to reduce the emissivity and gloss of the coating. The surface morphology and chemical composition of pure and modified Al powders were characterized by scanning electron microscopy and X-ray diffraction. The infrared emissivity of the product was measured by an infrared emissometer. The influences of the modified Al powder content, substrate material, coating thickness, and aging time on infrared emissivity were systematically investigated. The results indicate that modified Al powder decreases not only the gloss of the coating, but also its emissivity within the wavelength range of 8–14 μm. The polyethylene wax/Al composites have a homogenous sheet structure at 30 wt.% Al content, and a lower infrared emissivity. The optimum content of modified Al powder is around 18 wt.%. The coating exhibits a lower emissivity value and excellent optical properties. The infrared emissivity of the composite coating significantly increases with increased thickness, and approaches a constant value when the thickness is more than 80 μm. Accelerated aging test results show that with increased aging time, the coating with modified Al powder has a better aging resistance and lower infrared emissivity than that with pure Al powder.     

Novel high‐performance wave‐transparent aluminum phosphate/cyanate ester composites

Advanced wave‐transparent composites are the key materials for many cutting‐edge industries including aviation and aerospace, which should have outstanding heat resistance, low dielectric constant and loss as well as good mechanical properties. A novel kind of high‐performance wave‐transparent composites based on surface‐modified aluminum phosphate AlPO₄(KH‐550) and cyanate ester (CE) was first developed. The dielectric and dynamic mechanical properties of AlPO₄(KH‐550)/CE composites were investigated intensively. Results show that AlPO₄(KH‐550)/CE composites have decreased dielectric loss and higher storage moduli than pure CE resin; in addition, the composites with suitable AlPO₄(KH‐550) concentration remain the outstanding thermal property and low dielectric constant of pure CE resin. The reasons attributing to these results are discussed from the effects of AlPO₄(KH‐550) on the key aspects such as morphology, curing mechanism, and interfacial adhesion of composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

十八胺改性纳米SiO2制备及在水性环氧防腐涂料中的应用

摘要：以正硅酸四乙酯（TEOS）、十六烷基三甲基溴化铵（CTAB）、γ-(2，3-环氧丙氧基)丙基三甲氧基硅烷（KH560）为原料，采用溶胶-凝胶法制备表面环氧基化的纳米SiO2，通过十八胺（ODA）的伯胺端基与纳米SiO2表面的环氧基进行反应得到ODA-SiO2，用于制备水性环氧防腐涂料。通过傅里叶变换红外光谱（FTIR）、热重测试（TG）、X射线光电子能谱仪（XPS）、扫描电镜（SEM）表征ODA成功接枝到SiO2表面；通过电化学测试、耐盐雾性能测试对水性环氧涂层的防腐性能进行了分析。结果表明，含0.3wt%ODA-SiO2的水性环氧涂层具有较好的防腐蚀性能，耐盐雾时间500h。     

三元乙丙橡胶低红外发射率涂层的制备与表征

为制备低红外发射率涂层,优选了三元乙丙橡胶(EPDM)为粘结剂、漂浮性片状铝粉(约15 μm)为填料,用流延自成膜法制备涂层.研究了溶剂种类和填料质量分数对涂层红外发射率的影响,并对涂层的物相和微观形貌进行了表征.研究结果表明:EPDM具有良好的红外透明性;二甲苯为溶剂时,涂层发射率最低为0.686;环己烷为溶剂时,铝粉显示出更好的漂浮性,涂层发射率可低至0.358;涂层在室温环境中具有一定的耐候性.制得的涂层可以用作低红外发射率隐身材料.     

Properties and interfacial bonding of regenerated cellulose films coated with polyurethane–chitosan IPN coating

Water-resistant films were prepared by coating a castor oil-based polyurethane–chitosan (PU–CH), in which grafted interpenetrating polymer networks (IPNs) were produced, on a regenerated cellulose (RC) film. The tensile strengths of the coated films cured at 90°C for 5 min reached 853 kg cm⁻² (dry state) and 503 kg cm⁻² (wet state) and were obviously higher than those of the films of uncoated and coated with PU coating. Moreover, the coated films have excellent water resistivity, low vapor permeability, and good size stability, and their optical transmittance is even better than that of the RC film in the range of 400–800 nm. The interfacial structure of the coated films was investigated by using spectroscopy infrared, ultraviolet spectroscopy, transmission electron microscopy, and electron probe microanalysis. It was shown that the strong interfacial bonding with chemical and hydrogen bonds between the RC film and the coating exists. The PU prepolymer in the IPN coating penetrated through the interface into the RC film and partly crosslinked with the cellulose, forming a semi-IPNs. The chitosan in the PU–CH coating plays an important role not only in accelerating the cure of the coating but also in improving the mechanical properties and biodegradability of the coated film. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1313–1319, 1998     

Development and molecular dynamics simulation of green natural rubber composites with modified sisal microcrystalline cellulose

In this study, green composites were prepared using natural rubber (NR) as the matrix and the sisal microcrystalline cellulose (MCC) as the filler. Three modifying agents oleic acid (OA), γ-aminopropyltriethoxylsilane (KH550), and bis-γ-(triethoxysilylpropyl)-tetrasulfide (Si69) were individually tested to modify the MCC to improve the interfacial compatibility of the NR and MCC. Combined with modern instrumental analysis technology and molecular dynamics simulation, the reinforcing effect and microscopic mechanism of modified MCC on NR were analyzed. The structure–activity relationship of NR and MCC composites was further revealed, and the interaction between the two components was clarified. At the same time, the reinforcing and compatibilizing effect of three kinds of modified MCC in NR matrix were also revealed. The results showed that the properties of NR/Mod-MCC composites were better than those of NR/MCC composites, where NR/OA-MCC presented the highest tensile strength, followed by NR/Si69-MCC. In addition, NR/Si69-MCC exhibited higher elongation at break and NR/KH550-MCC exhibited higher vulcanization characteristics. Molecular model systems were constructed through molecular dynamics simulation to investigate the interactions between the three modified cellulose molecules and the NR molecules. OA-cellulose has a better interaction with NR than KH550-cellulose and Si69-cellulose, The simulation results were consistent with the experimental results.     

Effect of silane KH‐550 to polypropylene/brucite composite

The effect of the KH‐550 type silane coupling agent on the properties of polypropylene (PP)/brucite (BC) composite was studied. X‐ray diffraction, scanning electron microscope, and polarization optical microscope indicated that morphology structure of PP changed with the addition of KH‐550, which activated the heterogeneous nucleation centers on BC surface, which made the distribution of the spherulite diameter become narrow and uniform, and improved the dispersibility of BC in the matrix. Therefore, KH‐550 enhanced the interfacial adhesion of matrix‐filler and improved the compatibility of the PP/BC composite, when KH‐550's content was 2.9% the tensile strength and impact strength increased approximately by 90% and by 30%, respectively than PP/BC. Flow tests and IR proved that some reactions took place between BC and KH‐550. All the investigations showed KH‐550 was a proper coupling agent in the PP/BC composite. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

表面处理对可生物降解黄麻/PLA复合材料结构和性能的影响

采用注塑成型法制备了生物降解黄麻短纤维增强PLA复合材料,通过力学性能测试及SEM,探讨了碱处理、碱和硅烷偶联剂KH550同时处理对复合材料结构和性能的影响。结果表明:两种处理方法均能够增加黄麻纤维的表面粗糙度,但碱和偶联剂KH550同时处理的效果要优于碱处理,且KH550改善了黄麻短纤维与PLA树脂之间的界面黏结性能提,高了黄麻/PLA复合材料的拉伸强度和弯曲强度。     

铝合金基体上多层组合镀层的耐蚀性研究

本文结合电化学腐蚀原理及产品实际使用环境,在镍-磷合金/金双镀层基础上建立了镍-磷合金/铜/镍-磷合金/金的多层组合镀层,分析了多层组合镀层的腐蚀机理,并对其耐蚀性能进行了验证。结果表明,镍-磷合金/铜/镍-磷合金/金的多层组合镀层可满足航空产品耐192 h盐雾腐蚀的使用要求,可有效提高材料的防护性能。     

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。     

硅烷偶联剂对纳米Al2O3改性的研究

本工作以改善纳米粒子在环氧树脂基体中的分散性,提高无机粒子与基体的界面结合力为目的,选择了硅烷偶联剂KH550和KH570分别对纳米Al2O3粒予表面进行改性。文章系统研究了各种聚合条件（加料顺序、偶联剂加入量、反应时间）对改性效果的影响。TGA测试表明获得了不同接枝率的改性粒子。改性粒子与环氧树脂反应后进行的TGA测试以及FTIR测试证明了KH550改性的纳米粒子能够与环氧树脂发生反应,而KH570改性的纳米粒子不能发生反应。