Preparation and Characterization of Carboxyl-terminated Poly(butadiene-co-acrylonitrile)-epoxy Resin Prepolymers for Fusion-bonded-epoxy Powder Coating

Liquid carboxyl-terminated poly（butadiene-co-acrylonitrile）（CTBN）-epoxy resin（EP） prepolymers were prepared with different contents of CTBN.The chemical reactions between EP and CTBN were characterized by Fourier ransform infrared（FTIR） spectroscopy and gel permeation chromatography（GPC）.The scanning electron micrograph（SEM） and dynamic mechanical analysis（DMA） of curing films showed phase separation,and the rubber particles were finely dispersed in the epoxy matrix.Mechanical properties analysis of curing films showed that impact strength and elongation at break increased significantly upon the addition of CTBN,indicating good toughness of the modified epoxy resins.Thermogravimetric analysis（TGA） showed that the incorporation of CTBN had little effect on the thermal stability of EP.Fusion-bonded-epoxy（FBE） powder coatings modified with CTBN-EP prepolymers were prepared.The experimental results demonstrate the ability of CTBN-EP prepolymers,toughening technology to dramatically enhance the flexibility and impact resistance of FBE coatings without compromising other key properties such as corrosion protection.

Corrosion resistance of waterborne epoxy coating pigmented by nano-sized aluminium powder on steel

A novel kind of waterborne epoxy coating pigmented by nano-sized aluminium powders on high strength steel was formulated. Several coatings with different pigment volume content (PVC) were prepared. The coating morphology was observed using scanning electron microscopy (SEM), and the electrochemical properties were investigated by electrochemical impedance spectroscopy (EIS). Immersion test and neutral salt spray test were also conducted to investigate the corrosion resistance of the coating. It is demonstrated that the critical pigment volume content (CPVC) value is between 30% and 40%. The coating with PVC of 30% exhibits good corrosion resistance in 3.5% (mass fraction) NaCl solution.

Developing polydopamine modified molybdenum disulfide/epoxy resin powder coatings with enhanced anticorrosion performance and wear resistance on magnesium lithium alloys

Epoxy resin powder coating has been successfully applied on the corrosion protection of magnesium lithium alloys.However,poor wear resistance and microcracks formed during the solidification have limited it extensive application.There are limited approaches to exploit such anti-corrosion and mechanical properties of magnesium lithium alloys.Herein,the epoxy resin powder coating with polydopamine modified molybdenum disulfide(MoS_(2)@PDA-EP powder coating with 0,0.1,0.2,0.5,1.0 wt.%loading)was well prepared by melt extrusion to investigate its anticorrosion performance and wear resistance.The results revealed that the addition of MoS_(2)@PDA enhanced the adhesion strength between coatings and alloys,wear resistance and corrosion protection of the powder coatings.Among them,the optimum was obtained by 0.2 wt.%MoS_(2)@PDA-EP powder coating which could be attributed to well dispersion and efficient adhesion with coating matrix.To conclude,MoS_(2)@PDA-EP powder coating is meaningfully beneficial for the anticorrosive and wear performance improvement of magnesium lithium alloys.

Curing Kinetics, Mechanical Properties and Thermal Stability of Epoxy/Graphene Nanoplatelets(GNPs) Powder Coatings

Epoxy/graphene nanoplatelets（GNPs） powder coatings were fabricated using ultrasonic predispersion of GNPs and melt-blend extrusion method. The isothermal curing kinetics of epoxy/GNPs powder coating were monitored by means of real-time Fourier transform infrared spectroscopy（FT-IR） with a heating cell. The mechanical properties of the epoxy/GNPs cured coatings had been investigated, by evaluating their fracture surfaces with field-emission scanning electron microscopy（FE-SEM） after three-point-bending tests. The thermal stability of the epoxy/GNPs cured coatings was studied by thermo-gravimetric analysis（TGA）. The isothermal curing kinetics result showed that the GNPs would not affect the autocatalytic reaction mechanism, but the loading of GNPs below 1.0 wt % additive played a prompting role in the curing of the epoxy/GNPs powder coatings. The fracture strain, fracture toughness and impact resistance of the epoxy/GNPs cured coatings increased dramatically at low levels of GNPs loading（1 wt %）, indicating that the GNPs could improve the toughness of the epoxy/GNPs powder coatings. Furthermore, from FE-SEM studies of the fracture surfaces, the possible toughening mechanisms of the epoxy/GNPs cured coatings were proposed. TGA result showed that the incorporation of GNPs improved the thermal stability of the cured coatings. Hence, the GNPs modified epoxy can be an efficient approach to toughen epoxy powder coating along with improving their thermal stability.

Preparation of Silica Powder in Epoxy Resin Wear-Resistant Coating

Silicon powders possess good thermal stability and rub resistance and can be used as the filler of high temperature wear-resistant coating;it can possess good wettability and dispersibility in the organic polymer by surface modification of silane coupling agent. Organic silicon has good thermal stability, which can modify the frangibility and thermal stability of epoxy resin. A certain proportion of modified silica powder, curing agent and additives were dispersed to modified epoxy resin can compound wear-resistant coating. The results show that: the modification effect can be the best if the dosage of silane coupling agent is 1.5% of silicon powder. If the methyl triethoxy silane is 50 phr and modified silica powder is 200 phr, then various performances of coating tend to be the best.

Effects of direct stray current on the performance of cathodic disbonding epoxy powder coatings

The influence of the direction and magnitude of direct(DC)stray current on the disbonding performance of epoxy powder coating was studied by using electrochemical impedance spectroscopy and scanning electron microscopy technology.The results show that the application of DC stray current could accelerate the anodic dissolution.The peeling degree of the coating increases as the magnitude of positive DC stray current interference increases in the range of 2–8V.With 16V positive stray current disturbance,the degree of coating disbonding decreases.With the application of negative stray current,the coating peeling becomes more serious,and the degree of peeling increases as the DC stray current increases.

Mechanical Properties of Epoxy Composite Materials Produced with Different Ceramic Powders

In this study, production and mechanical properties of polymer composite materials obtained by using Al2O3, SiO2, MgO and TiO2 hard ceramic fillers were studied. Epoxy resin was used as the matrix material, and four different ceramic powders were mechanically mixed into the resin at 3% and 5% as reinforcement. The mechanical properties of the polymer composite materials were then characterized. For this purpose, flexural modulus and flexural strength of composite materials were determined by using three point bending test and impact toughness of the materials were determined by Charpy impact test. In addition, the hardness values of the samples were determined by Shore D hardness test.

Effect of Curing Procedure on the Properties of Copper-Powder-Filled Conductive Adhesives

By means of testing the shear strength with single lap joint, measuring electrical resistivity for cured products and the curing strain with strain gauges, the effect of cure parameters on the properties of HT1012 conductive adhesive filled with copper powder was investigated, and the residual stress in the conductive adhesives was also estimated. The experimental results show that the properties such as shear strength of the adhesives, electrical resistivity of products as well as the residual stress of cured HT 1012 copperfitted conductive adhesive were evidently affected by curing temperature and time. The diagrams of scanning electron microscopy （SEM） and Fourier transform infrared （FT-IR） were also used to determine the properties. The higher mechanical property was achieved under the condition of curing the adhesive 3 h at 60 ℃ as the density of the hydrogen links or linkages existed in the adhesive was relatively higher and the lower electrical resistivity occurred at 80 ℃.

低温固化聚酯粉末涂料的研究与应用

以热固性聚酯粉末涂料为研究对象,介绍了成膜物质中聚酯树脂和固化剂的特性及其在粉末涂料中的作用,并从制备、固化机理、改性、应用4个方面综述低温固化聚酯粉末涂料的研究进展。为改善聚酯粉末涂料出现缩孔的问题,将活性官能团丙烯酸酯引入聚酯树脂中进行表面改性,得到聚酯/丙烯酸混合型粉末涂料,并对耐候性聚酯/丙烯酸粉末涂料的耐候性及固化反应原理进行概述。为降低粉末涂料的固化温度,使其符合低温固化的发展要求,针对合成聚酯粉末涂料成膜物质的相对特性,在树脂合成过程中引入环氧型官能团作为功能单体或直接与环氧树脂混合。聚酯粉末涂料已在家具、汽车及家用电器领域得到广泛应用。未来,聚酯粉末涂料朝着节能环保、多样性和更广泛的适用性发展。

铁粉/碳纤维增强树脂复合材料的制备 及脆化损伤研究

将偶联剂改性纳米铁(Fe)粉与预处理后的碳纤维混合,浸润于环氧树脂基料中,经过搅拌混合制备纳米Fe粉/碳纤维增强树脂复合材料,研究了复合材料在高温老化、水浸老化环境下的脆化损伤行为。结果表明:树脂受到高温老化和水浸泡老化后会出现脆化损伤,碳纤维和纳米Fe粉加入会对该损伤有一定抑制;加入质量分数为4.0%的纳米Fe粉后,随着高温老化时间延长,碳纤维质量分数为3.0%的纳米Fe粉/碳纤维增强复合材料的拉伸强度、断裂韧性下降幅度较小,同时脆化损伤后树脂与纳米Fe粉、碳纤维仍结合紧密;碳纤维质量分数为3.0%、纳米Fe粉质量分数为4.0%的纳米Fe粉/碳纤维增强复合材料经水浸老化后,断裂韧性仍旧保持较高水平。

冷涂烯锌涂料的制备与性能研究

首先研究了不同环氧树脂(E20、E44和E51)对环氧含锌涂层基本性能的影响,其次探究了纯薄石墨烯的添加对涂层防腐蚀性和力学性能的影响,确定了锌质量分数30%涂料体系中纯薄石墨烯的最佳添加量,最后考察了膨润土、聚脲、聚酰胺钠作为防沉体系对冷涂烯锌涂料贮存稳定性的作用。通过中性盐雾试验,并结合扫描电镜、表面电阻率、剩余锌含量和力学性能测试,制备出符合T/CHTS 10105—2023标准要求的冷涂烯锌涂料。结果表明:采用环氧树脂E44所制备的涂层基本性能最佳;加入质量分数0.5%纯薄石墨烯后,涂层的力学性能均有提升,表面电阻率≤10^(6)Ω,锌粉利用率超过80%,耐中性盐雾时间可达3000 h;添加质量分数0.9%膨润土、0.6%聚脲和1%聚酰胺钠防沉体系后,冷涂烯锌涂料可在50℃下稳定贮存60 d。

石化储罐水性导静电防腐涂料制备及性能研究

为解决石化储罐在储存、运输过程可能由于积聚电荷产生的安全隐患,以及水性导静电涂料耐腐蚀性差的问题,以环氧类乳液及导电云母粉为主要原料制备导静电涂层,通过水热法制备了碳纳米点,将其以不同比例添加,增强涂层的防腐性能。并对涂层进行耐化学浸泡实验、耐盐雾实验以及力学性能测试。结果表明选用浙江安邦新材料发展有限公司的环氧乳液A与固化剂A作为成膜物,导电云母粉质量含量为15%,碳纳米点质量含量为1%的涂层表现最为良好。

烷氧基硅烷低聚物改性球形硅微粉及其应用

分别以自制乙烯基烷氧基硅烷低聚物、氨基烷氧基硅烷低聚物、多元烷氧基硅烷低聚物为改性剂,对液相法球形硅微粉进行表面改性,通过红外光谱、扫描电镜、粒度分布仪等表征了改性剂的结构、硅微粉微观形貌及粒径分布,并考察了改性硅微粉对环氧树脂力学性能的影响。结果表明,采用实验合成的改性剂对液相法球形硅微粉进行表面处理后,硅微粉的粒径增大且尺寸均一性提高,硅微粉颗粒间夹杂碎片杂质的情况得到改善,添加到环氧树脂体系后材料的力学性能提高。

一种无溶剂型电子封装用导电胶的研制

为了解决导电胶黏剂因综合性能不足而导致大规模应用的受限,本文以酚醛环氧、多官能环氧为导电胶树脂基体,选用了4,4′-二氨基二苯砜(DDS)作为固化剂,片状银粉作为导电填料,通过调节银粉和固化剂的用量,制备了有良好流变性、导电性、力学性能的导电胶。通过分析测试,得到导电胶的黏度为32 800 mPa·s,触变指数为4.0,体积电阻率为4.34×10^(-4)Ω·cm,剪切强度为17 MPa,热导率为3.96 W/(m·K),Cl^(-)、Na^(+)和K^(+)分别仅为6.79×10^(-5)、6.31×10^(-5)和<10^(-5)。该导电胶综合性能优异,可应用于电子元器件及其他导电导热功能性材料的粘接。

填料含量对高导热玻璃纤维增强环氧树脂复合材料性能的影响

采用氧化铝和硅微粉混合填料填充双酚A型环氧树脂体系,制备了高导热玻璃纤维缠绕增强环氧树脂复合材料。研究了填料用量对缠绕复合材料力学性能、电气性能和导热性能的影响。结果表明:混合填料的加入有利于提高复合材料的热稳定性和导热性。当填料质量分数为62%(其中硅微粉质量分数为48%,氧化铝质量分数为14%)时,缠绕复合材料的单向板拉伸强度(0°和90°方向)、单向板弯曲强度以及NOL环拉伸强度分别为160.25、24.50、245.40、134.30 MPa,介电常数为1.889,介质损耗因数为0.673×10^(-2),体积电阻率为3.36×10^(16)Ω·cm,热导率为1.257 W/(m·K),相比添加前的导热系数提高了155%。

粉状环氧树脂固化改性IXPE发泡材料的制备及性能研究

采用化学发泡法和辐照交联工艺成功制备了一系列聚乙烯/双酚A环氧树脂/双氰胺(LDPE/E-20/DCD)复合发泡材料,探究了E-20/DCD固化含量对LDPE/E-20/DCD复合发泡材料的表观密度、凝胶含量、力学性能、吸水率和隔音性能的影响。结果表明,当E-20/DCD固化含量为10%时,LDPE/E-20/DCD复合发泡材料具有较优的综合性能。相比纯辐照交联聚乙烯发泡材料(IXPE)发泡材料,其表观密度提高2.7%,凝胶含量提高5.9%,拉伸强度提高36.6%,压缩强度提高23.4%,压缩模量提高11.8%,硬度提高61.2%,隔声指数提高22.5%,同时具有优异的泡孔结构。

长余辉粉体的含量和分散对环氧树脂性能的影响

将长余辉粉体(LAP)分散于树脂涂层制备的蓄能自发光涂层在安全标识领域具有广阔的应用前景,LAP在树脂中的分散性对涂层材料性能具有重要影响。以环氧树脂(EP)为基体,以球磨共混的方式在EP基体中加入不同含量的LAP用以制备EP/LAP自发光复合材料。研究了不同LAP含量及球磨工艺对复合材料结构、发光效果、摩擦性能及力学性能的影响。利用扫描电子显微镜和傅里叶变化红外光谱观察和分析了EP/LAP复合材料的断裂形貌和各组分相互作用。结果表明,球磨有效改善了LAP在EP中的分散性,提升了材料发光均匀性、热稳定性、力学性能,降低了摩擦系数。LAP未对EP的化学固化反应过程产生影响,两者未发生化学反应,EP/LAP复合材料可以实现有效固化。LAP含量过高不利于复合材料的力学性能和摩擦性能。在LAP添加量为5份时,经球磨制备的EP/LAP复合材料具有最佳的综合性能,摩擦系数降低至0.12,拉伸强度提升至28.77 MPa,同时发光均匀性得到有效提升。此外,EP/LAP复合材料表现出良好的发光效果。

管道熔结环氧粉末外涂层抗冲击试验装置的设计

为了解决国内现有冲击试验机不能满足标准对管道熔结环氧粉末外涂层抗冲击试验要求的问题,设计了管道熔结环氧粉末外涂层抗冲击试验装置。使试验装置各冲击点之间的距离均大于50 mm,新装置的启用不仅使熔结环氧粉末外涂层抗冲击试验设备能够符合标准要求,操作简便,而且提高了试验准确度和试验效率,可为类似的抗冲击试验机的改进设计提供借鉴方法。

低线膨胀系数导热环氧树脂的制备与性能评价

不断集成化和精细化的电子设备对环氧树脂材料的散热性和低线膨胀系数等提出了更高的要求,未进行表面改性的硅微粉填料在环氧树脂中的分散性较差,进而导致所制备的环氧树脂材料在特殊条件下使用受限。为了克服上述难题,本文采用硅烷偶联剂KH550对硅微粉进行表面改性,并对硅微粉的改性效果及复合材料的力学性能、电绝缘性能和热稳定性等进行了研究。结果表明,经过KH550改性后,硅微粉的聚集程度和表面亲水性发生了变化,进而使得制备的复合材料具有更好的力学性能、电绝缘性能和热稳定性。改性硅微粉质量分数为70%的环氧树脂复合材料的导热系数和线膨胀系数分别为0.787 W/(m·K)和2.83×10^(-5)℃^(-1),分别为纯环氧树脂的432%和46%,同样也优于添加相同质量分数的未改性硅微粉时的0.702 W/(m·K)和3.41×10^(-5)℃^(-1)。

功能化球形氧化硅制备及其在环氧塑封料中的应用性能研究

采用不同种类和不同用量的硅烷偶联剂对球形氧化硅粉进行表面功能化处理,以XRD、FTIR、BET、SEM等手段对功能化表面改性前后样品的晶体结构、表面基团、孔道结构、微观形貌进行表征,以激光粒度仪、接触角、吸油值表征了功能化改性产品粒径与疏水吸油性能。结果表明,表面功能化后球形氧化硅晶体结构无显著变化,表面接枝有机基团,比表面积有所降低,且具有良好分散性能,接触角从17°增大到125°,吸油值从52.1 mL/100 g降低到36.1 mL/100 g,亲水性显著降低,亲油性明显提高。将功能化球形氧化硅作为填料用于环氧塑封料,采用螺旋流动长度、凝胶化时间、弯曲强度、飞边值和黏度等技术指标进行表征。结果表明,添加功能化后球形氧化硅粉的环氧塑封料螺旋流动长度从106.7 mm增加到134.6 mm,凝胶化时间从25 s增加到33 s,飞边值有所降低,弯曲强度则从142 MPa提升到155 MPa,黏度从13.31 Pa·s降低到8.39 Pa·s,表明功能化氧化硅粉与环氧树脂具有良好的相容性和分散性,明显提升了球形氧化硅粉应用性能。