喷涂型抗爆聚脲高应变率力学性能及其涂层钢板爆炸模拟研究

为研究爆炸冲击荷载作用下喷涂型抗爆聚脲 MS-1对钢板的防护性能,对 MS-1进行了高速拉伸实验,研究了其在高应变率下的力学性能;运用 ANSYS/LS-DYNA有限元软件对 MS-1涂层钢板进行接触式爆炸模拟实验,获得小当量 TNT炸药作用下钢板的宏观破坏模式、位移变形和涂层能量传递规律;根据数值模拟的结果分析了 MS-1涂层对钢板的抗爆耗能机理。结果表明： MS-1具有良好的应变率效应,随应变率的提高其自身的力学性能也不断增强;相较于空白钢板,背爆面喷涂 MS-1涂层的钢板破坏程度减弱, 2 mm、4 mm和 8 mm涂层钢板中心点最大位移分别降低 14. 34%、 47. 01%和 49. 4%,MS-1涂层可以高效地将爆炸冲击能量转化为涂层自身的内能和动能,通过自身拉伸变形进行吸能和耗能。     

聚脲涂层对储油罐耐冲击性影响的研究

为避免储油罐发生意外碰撞造成巨大损失，考察了新型聚脲防护涂层对油罐车储油罐破坏变形的防护作用。通过储油罐耐冲击实验，分析了不同涂覆方式对聚脲复合涂层耐冲击性的影响，最后通过 LS-DYNA有限元模拟进行验证。结果表明：相比无涂层防护，聚脲涂层对储油罐具有良好的耐冲击防护效果，涂覆聚脲试样比无涂层试样最大变形位移减少了 18. 3 mm。在相同涂层厚度情况下， 2 mm Q190m和 2 mm Q413m聚脲复合涂层耐冲击效果最优，适合作为储油罐的防护涂层。     

环氧涂层提高Q235碳钢耐蚀性的研究

为改善Q235碳钢的耐蚀性,在其表面涂覆了1种环氧涂层。采用中性盐雾试验(NSS)、湿热试验、盐水全浸试验和电化学交流阻抗谱(EIS)对比了Q235钢涂覆前后的耐蚀性能。结果表明,Q235钢涂覆后在盐水中的平均腐蚀速率仅有38.8 mg/(m2·h),下降了86.3%以上,低频阻抗数值增加了3个多数量级,耐蚀能力显著提高。     

防爆罐用防爆材料及其性能的研究进展

随着防爆技术的不断发展,作为常用的公共安全防护装备,防爆罐的重要性变得越来越突出。基于试验和数值模拟两种研究方法,从防爆材料的防爆性能角度,综述了防爆罐在爆炸冲击载荷作用下的防护研究进展,指出了不同防爆材料及结构的抗爆性能和吸能效率,最后指出了常规防爆罐的结构和防爆性能存在的问题以及今后的发展趋势。     

BaO-A12O3-SiO2环境隔离涂层的制备与耐腐蚀性能表征

应用柠檬酸溶胶-凝胶法制备BaO-A12O3-SiO2(BAS)溶胶,将BAS溶胶直接刷涂在碳纤维(carbon fiber,Cf)/SiC-SiC基底上制备出BAS涂层,并在1 250℃,50%(体积分数,下同)H2O-5%O2和0.1 Mpa压力下对涂覆和未涂覆BAS涂层的样品进行腐蚀试验.用红外光谱仪、热重-差示扫描量热分析仪、X射线衍射仪、扫描电镜表征了BAS溶胶-凝胶及涂层的性能:采用电子天平、电子万能试验机对涂覆和未涂覆BAS涂层的样品耐腐蚀性能进行表征.结果表明:将pH控制在4～5,柠檬酸与金属离子Ba2+和Al3+的摩尔比分别为2和3时,可成功合成均匀、透明、稳定的BAS溶胶.BAS溶胶1次刷涂烧结的涂层厚度约为10 μm,4次可达50 μm左右.在1 250℃的水氧耦合条件下腐蚀200 h后,与未涂覆BAS的Cf/SiC-SiC比较,涂覆BAS的Cf/SiC-SiC强度保持率达88%,并且质量无明显损失.     

碳化硅涂层防刺织物的制备及防刺性能的研究

为了提高芳纶无纬布的防刺性能,采用碳化硅表面涂覆的方式制备防刺涂层织物。选择碳化硅粉体粒径、质量比和搅拌温度设计三因素四水平的正交试验,确定了最佳的碳化硅分散液的制备工艺——碳化硅粉体粒径为30μm、m_sic∶m_水∶m_乙二醇为2∶1∶1、搅拌温度为35℃。对涂层织物进行准静态和动态穿刺试验,探究碳化硅粉体粒径、涂层厚度和涂层结构对涂层织物防刺性能的影响,结果表明：防刺性能随着碳化硅粉体粒径和涂层厚度的增加呈现先增大后减小趋势;当碳化硅粒径为30μm、涂层厚度为75μm时,织物单位克重刺破强力达到最大值503 N/g,相较于未涂覆涂层织物提高了302%;面密度都为8.1 kg/m2的18层碳化硅涂层织物结构和16层芳纶无纬布+9层碳化硅涂层织物结构均可实现有效防刺,较未涂覆结构面密度降低了10%。     

电力开关柜散热涂层的制备及其性能研究

为提升电气设备散热性能，提高供配电稳定性，采用溶液共混法以氮化硼（BN）和远红外陶瓷粉（FICP）为填料，水性丙烯酸改性环氧酯（WEP）为成膜物，制备了电力开关柜母线散热用FICPBN/WEP涂层材料，研究了散热涂层的热导率、发射率、热稳定性和散热性能。结果表明：涂层热导率和发射率随填料含量增加，呈现先上升后下降的趋势，当BN质量分数为12.5%,FICP质量分数为12.0%时，涂层热导率和发射率达到最大值，分别为0.503 W/（m·K）、0.846。在电力开关柜三相母线表面涂覆散热涂层后，当母线温升达到稳定状态后，三相母线表面平均温度比涂覆前分别降低4.0 K、2.3 K、4.0 K。     

锑掺杂氧化锡 @氯氧化铋 /含氟聚氨酯复合透明隔热涂层的制备与性能研究

以自制的锑掺杂氧化锡（ ATO）@氯氧化铋（ BiOCl）水性分散液为填料,自制水性含氟聚氨酯（ WFPU）为成膜物,采用共混法制备了 ATO@BiOCl/WFPU复合涂层。通过 X射线衍射仪（XRD）、 X射线光电子能谱仪（ XPS）、扫描电子显微镜（ SEM）、紫外可见近红外分光光度计（ UV-VIS-NIR）和实验室自制隔热装置等仪器对其结构、形貌和性能进行了表征。结果表明： ATO@BiOCl复合粉体成功合成。当 ATO@BiOCl分散液含量为 6%（以自制 WFPU的质量计）时,玻璃涂层在 380~780 nm可见光透过率为 71. 2%;在 780~2 500 nm的能量阻隔率为 60. 4%;与仅涂覆 WFPU涂层相比,太阳模拟环境下保温箱温度下降了 6. 7 ℃。     

涂层对速凝3D打印水泥砂浆力学性能的影响

3D打印砂浆普遍存在层间界面粘结较弱、抗折强度较低的问题,而膨胀水泥浆涂层涂覆于砂浆表面可产生表层压应力,进而提升其抗折强度,作为界面剂涂覆于层间可同时增强其界面粘结强度。本文通过将硫铝酸盐水泥与膨胀剂混合而成的涂层涂覆于速凝3D打印砂浆的表面与层间,研究了该涂层对不掺纤维及掺0.5%(体积分数)玄武岩纤维3D打印砂浆试件力学性能的影响规律。结果表明,涂覆层间涂层对无纤维与掺纤维速凝3D打印砂浆的层间界面粘结强度提升率分别为21.4%、12.2%,同时对其抗压强度也有一定提升作用。仅涂覆表面涂层与仅涂覆层间涂层对3D打印砂浆的抗折强度提升效果相当;同时涂覆表面及层间涂层对3D打印砂浆的抗折强度提升效果最显著,与无纤维、掺纤维的无涂层试件相比,提升率最高分别可达44.2%、23.2%。涂层对于无纤维3D打印试件层间粘结强度及抗折强度的提升效果优于掺纤维试件。     

BaO-Al_2O_3-SiO_2环境隔离涂层的制备与耐腐蚀性能表征

应用柠檬酸溶胶–凝胶法制备BaO–Al2O3–SiO2(BAS)溶胶,将BAS溶胶直接刷涂在碳纤维(carbon fiber,Cf)/SiC–SiC基底上制备出BAS涂层,并在1250℃,50%(体积分数,下同)H2O–50%O2和0.1MPa压力下对涂覆和未涂覆BAS涂层的样品进行腐蚀试验。用红外光谱仪、热重–差示扫描量热分析仪、X射线衍射仪、扫描电镜表征了BAS溶胶–凝胶及涂层的性能;采用电子天平、电子万能试验机对涂覆和未涂覆BAS涂层的样品耐腐蚀性能进行表征。结果表明:将pH控制在4～5,柠檬酸与金属离子Ba2+和Al3+的摩尔比分别为2和3时,可成功合成均匀、透明、稳定的BAS溶胶。BAS溶胶1次刷涂烧结的涂层厚度约为10μm,4次可达50μm左右。在1250℃的水氧耦合条件下腐蚀200h后,与未涂覆BAS的Cf/SiC–SiC比较,涂覆BAS的Cf/SiC–SiC强度保持率达88%,并且质量无明显损失。     

Fire characteristics of steel members coated with nano‐enhanced polymers

Polymeric coatings applied to masonry infill walls have been demonstrated to provide protection against blast. Steel frames may be embedded in these walls to improve the structural characteristics of the building. During the process of retrofitting the walls with blast protection polymeric coatings, the steel frame may be fully or partially coated with these materials to provide adequate anchorage of the retrofit system to the frame and to avoid global failure of walls subjected to blast loading. The development of a blast‐resistant coating for masonry walls that safeguards all structural elements in a fire would provide buildings with protection against explosions and a fire following the blast, as well as against ordinary building fires. This paper uses a numerical tool based on the particle finite element method to evaluate the melting and dripping of nano‐enhanced polymeric coatings applied on steel members embedded within masonry walls. Viscosity measurements were performed to obtain needed parameters for the simulations. Polyurea nanocomposite residues showed a minimum in viscosity with temperature, possibly caused by cross‐linking and charring. Model results for the polyurea residue with the lowest value of minimum viscosity showed that the coating remained attached, although there was some flow that caused a chunk of material to break off from an overhang. Copyright © 2013 John Wiley & Sons, Ltd.     

Reduction of milk fouling inside gasketed plate heat exchanger using nano-coatings

Fouling inside gasketed plate heat exchangers used in milk production has been reduced using nano-composites coatings. An antifouling coating with low surface energy (low wettability) led to a hydrophobic and oleophobic effect. Test facilities were constructed by the Institute of New Materials (INM) and Institute of Environmental Process Engineering (IUV), University of Bremen in Germany for the investigation of milk adhesion and the stability of the coatings on rectangular plates and small cylindrical ducts. A number of coatings and surface treatments were tested. Certain polyurethane-coated plates and tubes formed thinner deposit layer compared to standard uncoated stainless steel plates and tubes. The cleaning time for one coated tube was reduced by 80% compared to the standard stainless steel one. A pilot plant including a milk pasteurizer at LUFA Nord-West in Oldenburg-Germany was used for the thermal treatment of whey protein solutions. Plates coated with different nano-composites as well as electropolished plates were installed in the heating section of the pasteurizer. Significant differences were observed between coated and uncoated plates. The coated plates showed reduced deposit buildup in comparison with the uncoated stainless steel plates. Polyurethane-coated plates exhibited the thinnest deposit layer. Electro-polished plates also reduced deposit buildup in comparison to the standard stainless steel plates and were almost comparable to the coated plates. The time required for cleaning in place (CIP) with the coated plates was reduced by 70% compared to standard stainless steel plates.     

The preparation and characterization of abrasion-resistant coatings on polycarbonate

A series of abrasion-resistant coatings based on methyltrimethoxysilane (MTMS), tetraethoxysilane (TEOS), and methacyloxypropyltrimethoxysilane (MEMO) were synthesized via a sol–gel method and applied to polycarbonate (PC) substrate. Through a comparison with an uncoated PC substrate, hardness, adhesion, and abrasion resistance of coated PC substrates were investigated. Fourier transform infrared (FTIR) spectra of these coatings before and after being cured indicated that the crosslinked structure of Si–O–Si was formed via the hydrolysis–condensation reactions of alkoxy silane. The optical test results showed that coated PC substrates possessed higher transmittance and lower haze than uncoated PC substrates. The hardness and adhesion data demonstrated that PC substrates coated with the hybrid coatings (MTMS/TEOS/MEMO coatings) possessed the greatest hardness and optimal adhesion. After 500 wear cycles, the PC substrate with MTMS/TEOS/MEMO coatings showed some grooves and wear tracks without any spallation or delamination, and there was a decrease of only 1.0–1.3% in transmittance and an increase of only 5.68–7.44% in haze. Whereas uncoated PC substrate and substrates with MTMS and MTMS/TEOS (molar ratio is 1.5:1) coatings exhibited a decrease of 3.3, 3.9, and 2.4% in transmittance and an increase of 30.19, 17.42, and 12.35% in haze, respectively.     

Evaluation of the corrosion barrier properties of nano‐reinforced vinyl chloride/vinyl acetate coatings

A poly(vinyl chloride/vinyl acetate) copolymer (VYHH) with and without multiwalled carbon nanotubes (MWCNTs) as reinforcements were used as a coating for steel substrates to evaluate their barrier properties against corrosion. Electrical impedance and thermal properties of the coatings were evaluated. The coatings were formulated with 0.1% MWCNT, by weight. Neat and nano‐filled VYHH was used to coat polished, degreased steel substrates via a dipping method. The substrates were either dipped once, for a target coating thickness of 30–40 μm, or twice for a target coating thickness of 60–75 μm. The coated and uncoated control samples were submerged in a tank with a 5% NaCl solution for a 45‐day period. Electrochemical impedance spectroscopy (EIS) revealed that coating thickness plays a role in corrosion resistance. EIS also showed that nano‐reinforced VYHH had the highest charge transfer resistance within its coating thickness. Fourier transform infrared spectroscopy (FTIR) indicated that hydrolysis occurred in the single coatings for both the neat and nanoreinforced coatings. Differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA) both showed that the addition of MWCNTs improved the thermal stability of the VYHH. DSC thermograms revealed that the thermal properties of the nano VYHH were largely unchanged after 45 days of submersion as compared with the unaged nano VYHH. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Novel bi-layered nanostructured SiO2/Ag-FHAp coating on biodegradable magnesium alloy for biomedical applications

In this study, a novel bi-layered nanostructured silica (SiO₂)/ silver-doped fluorohydroxyapatite (Ag-FHAp) coating was deposited on biodegradable Mg-1.2Ca-4.5Zn alloy via physical vapor deposition (PVD) combined with electrodeposition (ED). The nano-SiO₂ underlayer had a compact columnar microstructure with thickness of around 1 µm while the Ag-FHAp overlayer presented large plate-like crystals accompanied with small rounded particles with thickness about 10 µm. Potentiodynamic polarization test exhibited that the double layer SiO₂/Ag-FHAp coated Mg alloy has superior corrosion resistance compared to uncoated and single layer SiO₂ coated samples. Contact angle measurement showed that Ag-FHAp coating over nano-SiO₂ layers significantly increased surface wettability which is favorable for the attachment of cells. Cytotoxicity tests indicated that the nanostructured SiO₂/Ag-FHAp coating enabled higher cell viability compared to nano-SiO₂ coating and uncoated samples. In addition, bi-layer and single-layer coatings considerably improved the ability of cell attachment than that of the uncoated samples. The cell viability of coated and uncoated samples increased with increasing incubation time. The double layer SiO₂/Ag-FHAp coated biodegradable Mg alloy possessed high corrosion resistance and cytocompatibility and can be considered as a promising material for implant applications.     

Glass Strengthening by Polymer-Derived Ceramic Coatings

Polysilazane-derived ceramic coatings in the form of thin films (0.1 to 4 μm) — fabricated by dipcoating soda-lime rods with preceramic polymer solutions, followed by pyrolysis — increased the strength of the glass rods. Strengths up to 414 ± 57 MPa were obtained, 2.3 and 3.3 times higher than the strengths of uncoated/annealed and as-received rods, respectively. As-received coated glass was stronger than coated annealed glass. Microstructural damage was not observed in the optimal coatings.     

板式换热器Ni-P-TiO2复合纳米镀层微生物污垢特性

换热器微生物污垢问题普遍存在于能源化工领域，污垢的聚集会导致设备的流动阻力、燃料消耗和维护成本支出大幅度增加。本文采用复合纳米镀层来抑制和减轻换热表面的微生物污垢的附着和沉积。首先采用化学镀的方式，在板式换热器的不锈钢316板上镀覆 Ni-P-TiO₂复合纳米镀层和对照性的Ni-P 镀层。基于板式换热器的微生物污垢在线监测实验系统，研究了镀覆Ni-P-TiO₂复合纳米镀层的板式换热器微生物污垢特性。结果表明，清洁状态下，镀覆两种镀层的板式换热器其摩擦系数（f）和Nusselt数（Nu）相较未镀覆板式换热器均略有增加；微生物污垢实验后，相比较未镀覆的板式换热器，镀覆Ni-P镀层的板式换热器污垢热阻减少了8.36%~23.07%，而镀覆Ni-P-TiO₂复合纳米镀层的板式换热器污垢热阻减少了16.6%~30.96%；在相同微生物污垢实验工况下，镀覆Ni-P-TiO₂复合纳米镀层的板式换热器的摩擦系数（f）相比Ni-P镀层的低2.54%~11.82%，但Nu却明显高于Ni-P镀层达8.47%~9.45%，并且污垢热阻明显小于Ni-P镀层达10.66%~18.18%，镀覆Ni-P-TiO₂复合纳米镀层的板式换热器展现了优异的强化传热性能和抑垢性能。     

Synthesis and characterization of elastomeric polyurea foam

Polymeric foams are ubiquitous in impact mitigation for civilian and military applications; the performance in such loading scenarios can be elucidated through quasi-static and dynamic mechanical testing. The present study reports on the complex microstructure of newly synthesized polyurea foams exhibiting a hierarchical structure consisting of large perforated semi-closed spherical cells with a mean diameter of 370 ± 162 μm surrounded by smaller closed, spherical cells with size distribution of 69 ± 18 μm. The stress–strain curves were used to calculate the basic mechanical properties and to predict the dynamic behavior of the foams. Nonlinear regression and finite element analyses were used to calibrate the Ogden hyperfoam model to explicate the hyperelastic behavior. The performance of the polyurea foam was found to outperform a benchmark foam in nearly all the elastic and energy absorbing properties. For example, one variation of the newly synthesized foam stored nearly doubled the energy of the benchmark foam while being 12% lighter. Low-density polyurea foam was found to decelerate an incoming impact mass with a minimum G-level that was nearly one third lower than the higher density polyurea and benchmark foams. In all, the behavior of the foam is dependent on the parameters of the fabrication process. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48839.     

Styrene and butyl methacrylate copolymers and their application in leather finishing

Homopolymers and copolymers of styrene and butyl methacrylate were synthesized with different ratios by an emulsion polymerization technique with K₂S₂O₈/NaHSO₃ as the redox initiation system and sodium dodecyl sulfate as the emulsifier at 60°C for 3 h. The effects of different monomer ratios on the kinetics of emulsion polymerization and polymer viscosity were studied. These copolymers were applied to leather surfaces with a hand coater to a thickness of 18 μm. The effects of the coatings on the leather surfaces were evaluated through the measurement of physical and mechanical properties of coated and uncoated leather. IR spectra showed new bands characteristic of styrene and butyl methacrylate, which disappeared in the spectrum of uncoated leather. The physical and mechanical results showed that the water absorption content decreased with increasing styrene content, and the water vapor permeability of the coated leather was less than that of the uncoated leather; however, it was still in the acceptable range. The results indicated improvements in the tensile strength and elongation (%) for the coated leather with increases in the butyl methacrylate content. Thermogravimetric analysis showed characteristic improvements in the thermal stability of leather after the coating; its optimum stability was reached when the leather was coated with poly(styrene:butyl methacrylate) (1 : 1). Finally, scanning electron microscopy showed the full grain surface of the leather. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009