环氧树脂微胶囊的制备与性能研究

随着社会快速发展,人们对材料的安全性和耐久性越来越重视。复合材料在使用过程中,受到外界荷载、温度等环境作用,材料内部会产生微裂纹。将自修复材料微胶囊化,可修复材料微裂纹,改善材料耐久性,并提高复合材料使用寿命。本研究采用原位聚合法制备微胶囊,以尿素与甲醛作为壁材,环氧树脂E51为芯材制备,具有致密性较好,反应速率较快,且聚合物相对分子质量高等优点。在此基础上,本文系统地研究了合成工艺对环氧树脂微胶囊性能的影响。分析研究了微胶囊的形貌、化学结构、平均粒径,以及这些差异对微胶囊性能的影响。确定了影响微胶囊产率、芯材含量、抗渗透性、平均粒径的最大因素为反应时间。结果表明,制备的微胶囊为球形,粘性小,且成功将环氧树脂包覆在微胶囊中。测定最佳条件下微胶囊的产率和芯材含量分别为64.9%和69.6%。     

环氧片状模塑料用微胶囊固化剂的制备

以2-乙基-4-甲基咪唑(2E4MI)为芯材、聚乙二醇(PEG-6000)为壁材,采用熔融喷雾法制备了一种环氧片状模塑料用微胶囊固化剂。对微胶囊进行了表征,对环氧树脂的固化行为进行了研究。研究表明,该胶囊固化剂中囊芯材料2E4MI的质量分数约为l3.7%。ESMC的最佳固化工艺确定为:101℃/10min+111℃/10min+150℃/10min+180℃/10min。微胶囊化固化剂中的PEG-6000壁膜在常温下可以阻止环氧树脂的固化,使ESMC树脂糊体系具有更好的室温贮存稳定性。固化剂的微胶囊化不会引起固化机理的变化。环氧树脂的固化度α可达0.93。     

脲醛树脂包覆环氧树脂微胶囊的制备

以脲醛树脂为壁材,以被苯甲醇稀释后的E-44环氧树脂为芯材,采用原位聚合法制备了E-44环氧树脂自修复微胶囊。探讨了不同的乳化剂对环氧树脂乳化的影响,观察了微胶囊的形成过程;并对微胶囊的表面形貌、化学成分、热稳定性和粒径分布进行了分析。实验结果表明,以十二烷基苯磺酸钠(SDBS)作为乳化剂可以良好地乳化稀释后的E-44环氧树脂,制备的微胶囊呈规则的圆形,表面粗燥,粒径分布小,平均粒径为232.884μm,壁厚为3μm,热稳定温度为248℃,成功制备了脲醛树脂包覆环氧树脂微胶囊。     

微胶囊对环氧树脂体系性能影响的研究

采用原位聚合法以脲醛树脂为壁材,E-51环氧树脂为芯材制备了微胶囊并将其加入E-51环氧树脂/1622T改性脂肪胺体系中。采用示差扫描量热法及力学性能测试研究了该体系的固化动力学及其他性能。结果表明:微胶囊质量分数为10%时,体系的凝胶温度、固化温度和后处理温度均降低,固化度提高。活化能达到极小值45.02 kJ/mol,较纯环氧体系降低18.91%。冲击强度达到极大值2.58 kJ/m2,较纯环氧树脂体系提高20.34%。微胶囊质量分数为5%时,拉伸强度和弯曲强度分别为67.1 MPa和86.2 MPa,较纯环氧树脂体系分别提高6.5%和10.51%。     

MWCNTs改性PSF/润滑油微胶囊的制备及环氧树脂复合材料摩擦学性能研究

以MWCNTs改性的聚砜为壁材,润滑油基础油为芯材,采用溶剂挥发法制备了润滑油微胶囊。制备的微胶囊具有光滑的外表面及球形结构,直径为(100±28)μm,壁厚约为12μm,微胶囊芯材包覆率为56.84(wt.)%。制备了微胶囊/环氧树脂自润滑复合材料,当微胶囊壁材中MWCNTs添加量为5(wt.)%,复合材料中微胶囊含量为10(wt.)%时,复合材料的摩擦系数和磨损率分别比纯环氧树脂降低57.4%和92.2%,同时揭示了复合材料的自润滑机理。     

明胶微胶囊化技术研究进展

本文简要地介绍了微胶囊化技术及其分类方法,微胶囊的性质和主要的应用领域。对以明胶为基础的壁材体系、利用单凝聚和复凝聚方法制备微胶囊的过程、检测分析方法和微胶囊的释放机理等作了评述,并且指出了明胶微胶囊技术中尚未解决和需要进一步探讨的问题。     

路面材料自修复微胶囊制备工艺研究

以环氧树脂为囊芯,明胶和阿拉伯胶为囊壁,十二烷基硫酸钠(SDS)为乳化剂合成自修复微胶囊。考察了囊材和芯材的比例、反应时间、体系的pH、乳化剂的用量等因素对自修复微胶囊包覆率影响。确定了制备自修复微胶囊的最佳工艺:即囊材和芯材的质量比为10∶9,加入15 mL质量分数为4%的SDS为乳化剂,在pH低于4.0时持续反应3 h合成包覆率为69.9%的自修复微胶囊。     

自修复微胶囊制备及微纳力学性能

采用一步原位聚合法制备了自修复微胶囊。应用光学显微镜、扫描电子显微镜和激光共聚焦显微镜对微胶囊壁厚、微结构进行了分析和表征。借助纳米探针对微胶囊及其壳材进行压痕实验测试其力学性能。结果表明,自修复微胶囊包裹完整,表面粗糙,微胶囊平均粒径为100μm,平均壁厚为10μm,微胶囊修复剂芯材含量约为75%;纳米压痕分析显示微胶囊的弹性模量比环氧树脂的略小,说明了当环氧树脂基体内裂纹扩展时,裂纹更易于向微胶囊扩展,证明了环氧树脂微裂纹打开微胶囊释放修复剂的可行性。     

脲醛树脂胶黏剂的制备及其对木质乐器裂纹涂层性能的影响研究

自修复微胶囊作为一种可抑制木质乐器表面水性涂层微裂纹的新型有效途径,在音乐乐器涂料修复方面具备广阔的应用前景。对此,文章简述了树脂基微胶囊修复技术原理与研究现状,探究了脲醛树脂胶黏剂的制备与改性,以改性后的脲醛树脂胶黏剂为壁材、环氧树脂为芯材制备了微胶囊,添加到水性丙烯酸木器涂料中形成木器水性涂层,研究微胶囊的添加对木器水性涂层性能的影响。结果表明：脲醛树脂包覆环氧树脂微胶囊的芯壁材质量比为0.83∶1时,微胶囊分散均匀、形貌较好;在水性涂层中添加10%的微胶囊,水性涂层的综合性能较好;预制划痕试验表明,微胶囊含量为10%时,木器水性涂层裂纹的愈合程度较好。     

溶剂挥发法制备聚砜包覆桐油自修复微胶囊

以聚砜为壁材,桐油为芯材,采用溶剂挥发法制备了聚砜（PSF）包覆桐油自修复微胶囊。考查了不同种类的分散剂、搅拌速度、芯壁比（芯材与壁材的质量比）等工艺参数对微胶囊性能的影响,通过扫描电子显微镜、光学显微镜和热重分析仪等对微胶囊的表观形貌、粒径、壁厚、包覆率和热稳定性能等进行表征。采用所合成的微胶囊制备了环氧树脂基防腐蚀涂层,并对其防腐蚀性能进行了评价。结果表明,30 ℃时,以明胶/聚乙烯醇复配体系作为分散剂,芯材与壁材质量比为1.3:1,搅拌速度为700 r/min时制备出的微胶囊表面光滑致密,粒径在130 μm左右,热稳定温度为350 ℃;盐雾实验结果表明,所制备的微胶囊自修复涂层具有良好的防腐蚀性能。     

水性环氧涂料体系进展

概述了水性环氧涂料体系的研发状况。介绍了该体系中水性环氧树脂的制备方法、水性固化剂的种类以及助剂和颜填料的选择方法。对环氧树脂的各种制备方法包括乳化法（直接乳化法、相反转法和化学法）和成盐法的优缺点进行了总结,并给出了水性环氧涂料体系的配方实例。对水性环氧涂料体系在施涂中的涂装要求作了详细说明。     

中高温酸酐固化环氧树脂的自修复研究

基于兼具修复效率高、兼容性好、热稳定性较好等优点的微胶囊化环氧?胺自修复体系,研究了其在一种中高温（100~170 ℃）酸酐固化的商用环氧树脂中的自修复性能。首先研究了所选用修复剂的热稳定性及其在微胶囊化后在树脂基体中的热稳定性,进而采用人工预混注入修复剂的方法研究了所选用修复剂与酸酐固化环氧树脂的兼容性,最后在树脂基体中加入双组分微胶囊研究了该微胶囊化环氧-胺自修复酸酐固化环氧树脂的自修复性能,并探究了微胶囊比例与浓度及树脂固化程序对自修复性能的影响。结果表明,所选用的修复剂体系热稳定性较好,微胶囊化后在树脂基体中热稳定性较高,适用于酸酐中高温固化的环氧树脂的自修复,优化后的自修复效率较高,超过80 %。     

Cure kinetics of biphenyl epoxy resin system using latent catalysts

The investigation of the cure kinetics of a biphenyl epoxy–phenol resin system with different kinds of latent catalysts was performed by differential scanning calorimetry using an isothermal approach. All kinetic parameters of the curing reaction including the reaction order, activation energy, and rate constant were calculated and reported. The results indicated that the curing reaction of the biphenyl epoxy resin system in this experiment proceeded through an autocatalytic kinetic mechanism, irrespective of the kind of catalyst. The epoxy resin system with acid/diazabicycloundecene (DBU) salt as the latent catalyst showed a second overall reaction order; however, a third reaction order was represented for microencapsulated triphenylphosphine (TPP). The storage stability tests for these systems were performed, and a good shelf life was observed in the epoxy resin system with pyromellitic acid/DBU salt, trimellitic acid/DBU salt, and microencapsulated TPP as the latent catalyst. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2711–2720, 2001     

Effect of processing conditions on the microencapsulation of 1-methylimidazole curing agent using solid epoxy resins

Among various methods for preparation of the non-reactive or latent curing agents for epoxy resins, encapsulation offers a promising and cost-effective method. This system has been used in one-part thermosetting adhesives or prepregs for developing advanced composite materials. In this study, 1-methylimidazole (1-MI) was microencapsulated using solid epoxy resins via solvent evaporation method. The effect of various types of shell materials or solid epoxy resins, different core-to-shell ratios of 30/70, 50/50, and 70/30, and a variety of mixing rates (500, 1000, and 1500 rpm) on the preparation of microcapsules were evaluated. The 1-MI content and microencapsulation efficiency were calculated using thermal gravimetric analysis (TGA). The shape and surface morphology of the prepared microcapsules were evaluated using scanning electron microscopy (SEM) technique. Gel time of the microcapsules mixed with liquid epoxy resin was also investigated. Results showed that by decreasing the core-to-shell ratio at different stirring rates, the encapsulation efficiency increased. The microencapsulation efficiency of 34.8% was obtained at shell-to-core (1-MI) ratio of 70/30 at stirring rate of 500 rpm. The results also showed that at higher mixing rates, 1-MI content in microcapsules was controlled by high shearing force. It has been found that the gel time of the epoxy resin/microcapsule samples was proportional to the imidazole content and it was in agreement with the data obtained by TGA analysis, as well.     

水性环氧树脂的研究进展

本文简要地介绍了水性环氧树脂的原理和特点,系统地介绍了当前国内外水性环氧树脂的制备方法和研究现状,并对其在涂料方面的应用加以综述。     

Microencapsulation of 1-methylimidazole using solid epoxy resin: study on microcapsule residence time and properties of the system

In this study for the first time 1-methylimidazole was microencapsulated successfully by solid epoxy resin using solvent evaporation method. Fourier transform infrared spectroscopy, scanning electron microscopy, thermal gravimetric and differential scanning calorimetry were used for characterization of microcapsule and epoxy resin/microcapsule systems. The results revealed that although the solid epoxy shell was in contact with imidazole curing agent for a long time, it still remained as a thermoplastic. The chain length of the solid epoxy resin was grown in anionic polymerization process which led to an increase in the melting temperature from 64 to 78 °C. On the other hand, all epoxy functional groups of the shell did not participate in the curing reaction of resin with core curing agent of the microcapsule. The results showed that by increasing the residence time of the microcapsules, the number of epoxy groups of liquid epoxy decreased slightly but the rate of complex viscosity increase or the rate of curing reaction was increased and the cured epoxy system exhibited a single-phase morphology. On the other hand, in the presence of microcapsules the curing reaction of epoxy resin was successfully carried out and the curing temperature and the onset of viscosity increase or gel time at 120 °C were not more or less affected by sufficiently long contact time of epoxy and microcapsule.     

微胶囊红磷阻燃剂在环氧封装材料中的应用

研究了微胶囊红磷对环氧树脂基电子电气封装材料的阻燃性能、力学性能及抑烟性能的影响。结果表明：添加10份微胶囊红磷即可使材料的阻燃性能达到UL94V—O级，氧指数从19．5％上升到28．2％；添加量在一定的范围内对材料的力学性能影响很小，添加量从0增加至14份时，材料的拉伸强度略有下降，冲击强度有所上升，弯曲强度略有上升后有所降低；微胶囊红磷与硼酸锌的复配体系具有很好的抑烟性能。     

Microencapsulation of imidazole curing agents by spray‐drying method

An epoxy resin–imidazole system was used to form the adhesives for the anisotropic conducting film (ACF), and a latent curing system was necessary for the ACF. In this study, imidazoles were microencapsulated for the latent curing system. Polycaprolactone (PCL) was used as the wall material, and the spray‐drying method was used to form the microcapsule. The imidazoles used in this study were imidazole, 2‐methylimidazole, and 2‐phenylimidazole. The effect of the ratio of PCL to imidazoles, and the effect of PCL molecular weight were investigated during the microcapsule formation. The amount of imidazoles in the microcapsule was measured using thermogravimetric analyzer and elemental analysis. The permeability of the microcapsules was measured in ethanol, and the shelf life of the microcapsules was studied for the epoxy resin. The curing behavior of these microcapsules to epoxy resin was examined using differential scanning calorimeter. In the curing reaction, the microcapsule of imidazoles exhibited delayed kinetic behaviors compared to pure imidazoles. And the curing times were estimated at 150 and 180°C using an indentation method. These microcapsules of imidazoles exhibited a long shelf life, and the curing did not occur in some of the microcapsule–epoxy resin systems at 20°C for 15 days. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

环氧树脂水性化体系研究进展

系统地介绍了环氧树脂水性化的方法及研究进展,比较了各种方法的优缺点;阐述了水性环氧树脂体系的固化机理和常用水性固化剂及其改性方法;总结了目前环氧树脂水性体系的特点与应用。     

环氧树脂/石墨微片复合导电材料的制备方法

环氧树脂复合材料的制备一般要使用稀释剂,通过对环氧树脂/石墨微片复合导电材料的研究发现稀释剂不利于环氧树脂复合材料获得较低的电阻率和较好的结构性能。经过研究,改为在恒温箱中使环氧树脂升温降低粘度以分散填料,而不使用稀释剂,这种制备方法有利于复合材料获得较低的电阻率和较好的结构性能,是环氧树脂复合导电材料的一种有意义的制备方法。