复合材料表面膜的制备与性能研究

采用丙烯酸酯齐聚物改性合成了一种环氧基复合材料表面膜,并用丁腈橡胶增韧,芳香族二胺提高材料整体热性能。通过万能拉伸机、红外光谱、流变仪和热失重分析仪对其热性能、机械性能和老化性能进行了研究。研究了不同固化剂含量、增韧剂含量对体系整体性能影响。此外,当环氧树脂∶丙烯酸酯齐聚物∶固化促进剂质量比为100∶20∶5时,获得了优良的综合性能,经湿热老化后,室温下剪切强度超过20MPa,热分解温度超过290℃,其在耐高温胶黏剂领域具有良好的前景。     

互穿网络法增韧环氧树脂胶粘剂的研究

采用聚合物互穿网络法(1PN)研究了高性能环氧树脂胶粘剂的合成过程,互穿网络中作为增韧改性剂的第二组分为丙烯酸丁酯。实验结果表明:改性环氧树脂胶粘剂的剪切强度可达43．5MPa,增幅为22．7%。湿热老化试验结果表明:环氧树脂/丙烯酸丁酯IPN体系的抗湿热老化性能较好,胶粘剂的力学强度没有很大变化。     

抗水解剂及增韧剂对PBT耐湿热老化效果的影响

首先对特性黏度相近的不同牌号聚对苯二甲酸丁二酯(PBT)树脂在湿热老化试验后的强度和韧性保持率进行了比较;其次,考察了聚合型和单体型抗水解剂对PBT材料耐湿热老化性能的影响,并分析了聚合型抗水解剂用量与PBT耐湿热老化性能的关系;最后,对比了添加不同增韧剂的PBT材料经湿热老化试验后的力学性能保持率。结果表明,选用的5个牌号PBT树脂中,端羧基含量最低的树脂湿热老化900 h后拉伸和冲击强度保持率相对较好;添加聚合型抗水解剂较单体型可更为有效改善PBT材料的耐湿热老化性能,聚合型抗水解剂用量与材料力学性能保持率基本呈正向关系;含有甲基丙烯酸缩水甘油酯的增韧剂更有利于提升PBT材料耐湿热老化性能。     

混杂纤维增强环氧树脂复合材料电缆芯湿热老化性能研究

高温高湿条件下对玻璃纤维/碳纤维混杂增强环氧树脂复合材料电缆芯进行加速湿热老化试验,比较了两种直径的复合材料电缆芯在相同老化条件下的力学性能,并从微观角度分析了湿热老化后力学性能下降的原因。结果表明,该复合材料电缆芯耐湿热老化性能较好,在80℃及RH95%下老化1750h后其弯曲强度保留率大于65%,层间剪切强度保留率大于58%。     

高性能丙烯酸酯结构胶的研制

研究了环己酯的用量对改性丙烯酸酯结构胶力学性能的影响,制备出了一种力学、耐热性能优异的丙烯酸酯结构胶:环己酯的最佳用量为15%,其常温剪切强度为19.23MPa,高温老化后剪切强度为33.9MPa,湿热老化后剪切强度为17.39MPa。     

一种高性能芳纶纸蜂窝节点胶黏剂的研制

研制了一种芳纶纸蜂窝节点胶黏剂,该胶黏剂以环氧树脂和高邻位酚醛树脂为主体树脂,以活性端基的丁腈橡胶弹性体为增韧剂,以核壳橡胶和无机填料为流动控制剂,可在180℃固化。25℃剪切强度为34.6MPa,150℃剪切强度为14.1MPa,25℃蜂窝节点强度为5.6N/cm。该胶黏剂有较好的耐热性能和耐湿热性能,在150℃经过400h的热老化或是经过1000h的湿热老化后,依然具有良好的力学性能。     

一种室温快速固化的高强度环氧胶的研制

以聚硫醇固化剂为基本原料,酚醛环氧树脂与端环氧基封端丁腈橡胶为增韧剂,制备了一种室温快速固化、耐高温、耐湿热且韧性较好的环氧结构胶。研究了酚醛环氧树脂与增韧剂对胶粘剂粘接性能、耐高温和耐湿热老化性能的影响。结果表明,酚醛环氧树脂的引入,提高了体系的耐温性能,尤其是高温老化与湿热老化后的粘接强度显著增强;端环氧基封端丁腈橡胶增韧剂的适量加入,提高了环氧胶的韧性与粘接强度。     

功能性丙烯酸酯齐聚物增韧环氧胶的研究

以自制的功能性丙烯酸酯齐聚物增韧改性环氧胶 ,通过测定改性环氧胶粘剂的剪切强度、剥离强度 ,观察其断面的电镜照片 ,分析了增韧机理 ,发现改性环氧胶获得了较好的增韧效果 ,与原环氧胶比较 ,剪切强度 (τ)和剥离强度 (σ180° ,B)最大可提高 92 %和 12 0 %     

新型增韧剂在建筑结构胶中的应用

一种新型环氧树脂增韧剂——KH—07被成功地用于建筑结构胶。考查了KH-07的用量对胶粘剂综合性能的影响,结果表明,KH-07增韧剂能大幅提高胶粘剂的粘接剪切强度、冲击剥离强度和胶体自身强度,而且耐湿热老化性能也优于其他对照的增韧剂。另外,对KH-07增韧剂所产生的相分离现象也进行了初步探讨。     

半互穿网络法增韧环氧树脂胶粘剂的研究

利用半互穿聚合物网络法(Semi-IPN)对环氧树脂胶粘剂的合成及改性作了研究。结果表明:改性胶粘剂的剪切强度达47.8MPa,增幅为44.8%,且环氧树脂(丙烯酸丁酯Semi-IPN体系的抗湿热老化性能较好,胶粘剂的力学性能没有发生很大变化。这种现象可能与增韧剂聚丙烯酸丁酯和环氧树脂之间的相容性有关。     

钛合金的粘接件的湿热耐久性研究

采用拉伸剪切强度试验和楔子试验研究了钛合金TI— 6A1— 4V/改性环氧接头在湿热条件下的耐久性 ,考察了环氧胶固化条件、表面处理方法对胶接接头耐久性的影响 ,由此得出最佳条件以得到相当好的接头耐久性     

Factors Affecting the Durability of Ti-6Al-4V/Epoxy Bonds

Factors influencing the durability of Ti-6Al-4V/epoxy interphases were studied by determining chemical and physical properties of Ti-6Al-4V adherend surfaces and by characterizing the strength and durability of Ti-6Al-4V/epoxy bonds.

Ti-6Al-4V adherend surfaces were oxidized either by chemical etch or anodization. Four principal pretreatments were studied: chromic acid anodization (CAA), sodium hydroxide anodization (SHA), phosphate fluoride acid etch (P/F) and TURCO basic etch (TURCO). The oxides were characterized by SEM, STEM, profilometry, contact angles and XPS.

All adhesive bonding was carried out using a structural epoxy, FM-300U. Both lap shear and wedge test samples were tested in hot, wet environments. The results lead to the conclusion that the interfacial area between the adhesive and adherend is the primary factor affecting bond durability.     

Strength and Durability of Epoxy-Aluminum Joints

The adhesive strength and durability of adhesively-bonded aluminum joints in wet environments was analyzed. A2024-T4 alloy was subjected to two different surface treatments based on etching with chromic-sulfuric acid (FPL) and with sulfuric acid-ferric sulfate (P2). Small differences were observed in the lap shear strength as a function of the applied surface treatment. However, durability in humid environments was higher for the joints whose adherends were treated with P2.

Although the amount of water absorbed by the epoxy adhesive is lower in saline environments, the effects on the glass transition temperature of the epoxy adhesive and on the lap shear strength of the joints are more marked than the effects caused by aging with distilled water.

Finally, a new epoxy adhesive with a siloxanic hardener was tested, obtaining good mechanical properties, high glass transition temperature, moderate values of lap shear strength, and high durability in wet environments.     

The influence of zinc surface pretreatment on the adhesion of epoxy coating electrodeposited on hot-dip galvanized steel

The adhesion and electrochemical properties of epoxy coatings electrodeposited on hot-dip galvanized steel with and without passive films were investigated during exposure to 3% NaCl. The passive films were formed in hot air, in boiling water and by chromating. Adhesion was measured both by a standardized pull-off method and by swelling in N-methyl pyrrolidone. Pretreatment of hot-dip galvanized steel with passive film formed in hot air increases both dry and wet adhesion strength of the epoxy coating compared to pretreatment with passive film formed in boiling water and chromate coating. The overall increase of wet adhesion for this sample was maintained throughout the whole investigated time period. It was shown that the change in adhesion of epoxy coating on a chromate coating is smallest of all investigated samples, although the initial value of adhesion on this surface had the lowest value. The corrosion stability of coated Zn samples pretreated by different methods, was investigated by electrochemical impedance spectroscopy and in the initial time of exposure to NaCl the highest values of pore resistance were also obtained for the epoxy coating on Zn pretreated in hot air, whereas the epoxy coating on a HDG steel with a chromate coating showed the smallest change in electrochemical properties (pore resistance, coating capacitance, charge-transfer resistance) during prolonged exposure time.     

Wedge test of carbon‐nanotube‐reinforced epoxy adhesive joints

Epoxy adhesives reinforced with carbon nanotubes (CNTs) were developed. The distribution of the CNTs in the epoxy matrix was observed with transmission electron microscopy. Joints were formed by unclad 2024‐T3 aluminum adherents bonded with the CNT‐filled epoxy adhesives. The durability of the joints was studied with a wedge test under water at 60°C. The addition of CNTs to the epoxy greatly improved the adhesive joint durability. The initial crack length of the joint with 1 wt % CNTs, which was obtained before the wedge specimen was put into water, was only about 7% of that with neat epoxy. After immersion of the specimens in 60°C water, the joint with neat epoxy failed after 3 h, but all of the joints adhered with different fractions of CNTs were still bound together after the experimental time of 90 h. The significant enhancement by CNTs of the adhesive joint durability was mainly attributed to the high mechanical properties of the CNTs and their ability to resist water. Nevertheless, the experimental results also reveal that the durability of the joints showed an optimum value at approximately 1 wt % CNTs, beyond which a decrease in the property was observed. In addition, the failure mechanism of the joints was also investigated in terms of interfacial failure and cohesive failure. Cohesive dominated failure was found for the joint bonded with 1 wt % CNT‐filled epoxy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Adhesion and corrosion resistance of epoxy primers used in the automotive industry

One of the most important factors in corrosion prevention by protective coatings is the loss of adhesion of the coating under environmental influence. Thus, adhesion strength is often used when characterizing protective properties of organic coatings on a metal substrate. In this work, the adhesion of different epoxy primers (pigment-free, zinc-rich and chromate-based) was examined on steel. Both the dry and wet adhesion strengths of organic primers were measured directly by a pull-off standardized procedure, as well as indirectly by the NMP test. The corrosion stability of coated samples was investigated by electrochemical impedance spectroscopy. It was shown that under dry test conditions all the samples showed very good adhesion. However, different trends in adhesion for different primers during exposure to the corrosive agent (3% NaCl solution) were observed. The lowest adhesion values were obtained for chromate-based epoxy primer; however, the change in adhesion of this protective system during immersion in 3% NaCl solution for 25 days was the smallest of all investigated samples. Electrochemical impedance measurements in 3% NaCl solution confirmed good protective properties of pigmented epoxy primers on steel, i.e., greater values of pore resistance and charge-transfer resistance, and smaller values of coating capacitance and double-layer capacitance, were obtained for these protective systems.     

改性丙烯酸树脂在底面合一环氧涂料中的应用研究

底面合一涂料,不仅能够缩短施工时间,而且能够在一定程度上降低施工成本。环氧涂料因其耐腐蚀性好、耐候性差,常作为底漆使用。通过对丙烯酸树脂进行改性,使其具有活性胺基,将改性后的丙烯酸树脂作为固化剂与环氧树脂进行交联反应,制备了一种底面合一环氧涂料。该涂料不仅具有良好的耐腐蚀性能,而且具有优异的户外耐久性,具有广阔的应用前景。     

改性酸酐固化环氧树脂耐湿热性能研究

将改性酸酐与甲基四氢苯酐分别固化环氧树脂,研究了它们在经过湿热老化后表面电阻、体积电阻和介质损耗角正切值的变化。结果表明,双酚A环氧树脂与改性酸酐的固化产物电性能较好。     

Toughening of epoxy-polyamide adhesives with rubbery reactive microgels

An elastomeric microgel with reactive carboxyl groups was prepared by emulsion copolymerization of an unsaturated polyester with 2-ethylhexyl acrylate. An epoxy resin was grafted onto the microgel particles through the addition of the carboxyl group to the epoxy group. The blend of the microgel and the epoxy resin was very stable, the microgel remained as discrete microsphere in the cured resin. The incorporation of the microgel did not cause a significant effect on the network structure of the matrix resin, while the toughness and the adhesive strength of the epoxy-polyamide resins were improved tremendously.     

无溶剂环氧重防腐涂料的制备及性能测试

制备了一种无溶剂环氧重防腐涂料并进行了性能检测,分别讨论了环氧树脂、稀释剂、助剂、填料和固化剂对漆膜性能的影响。试验表明,添加环氧树脂量的20%的稀释剂2020对漆膜的防腐性能无不良影响,加入5%的湿法绢云母粉可以显著提高漆膜的抗介质渗透能力。