改性咪唑的合成及其促进EP/己二酰肼固化体系的研究

以顺丁烯二酸作为2-乙基-4-甲基咪唑(EMI)的改性剂,合成出一种潜伏性促进剂——改性咪唑,并采用红外光谱(FT-IR)法对其结构进行了表征。以己二酰肼作为环氧树脂(EP)的固化剂,考察了改性咪唑对EP/己二酰肼胶粘剂的凝胶时间、固化特性、室温储存期和粘接性能等影响。结果表明:当w(改性咪唑)=1.5%时,改性咪唑对EP/己二酰肼体系具有较好的促进作用(体系放热温度下降了20℃左右);该胶粘剂的固化条件为"110℃/1 h→130℃/1 h",室温储存期超过60 d,并具有粘接性能优、耐水性能好等特点。     

改性2-乙基咪唑环氧树脂潜伏型固化剂的制备

通过2-乙基咪唑(2EI)分别与N-(4-羟基苯基)马来酰亚胺(HPM)和三聚氯氰反应,成功地合成了两种改性2-乙基咪唑衍生物,分别采用红外光谱、核磁共振对其分子结构进行表征。将制备的改性咪唑类固化剂与环氧树脂混合,研究了树脂体系的固化特性和潜伏性。研究表明:相比EP/2EI体系,改性固化体系的固化放热区间均向高温区域移动;此外,改性固化体系在室温下具有更长的储存期。具有强吸电子效应的马来酰亚胺基团和三嗪环降低了咪唑环的亲核性,抑制了固化剂的室温固化活性。此外,在升温条件下,改性固化剂可以克服固化反应能量势垒,恢复快速固化能力。     

新型HT—0011环氧树脂潜伏性固化剂

湖北回天胶业股份有限公司最新研究开发一种新型环氧树脂潜伏性固化剂 ,该产品处于国内领先水平 ,属于胍、脲衍生物 ,具有固化及固化促进效果 ,可完全替代双氰胺、二酰肼类潜伏性固化剂。固化环氧树脂的温度降至 80～ 1 0 0℃ ,比纯双氰胺或二酰肼的固化温度 1 70～ 1 80℃ ,降低了近 1 0 0℃ ,并且在室温下具有良好的潜伏性 ,较长的贮存期 ,良好的环氧树脂固化性能。主要技术指标1、外观 :白色至灰黄色粉末2、粒度 :80～ 1 2 0目3、固化条件 (配单组分液体环氧胶 ) :固化温度 /℃ 80 1 0 0 1 2 0 1 40 1 6 0 1 80固化时间 /ｍｉｎ 1 80 6 0…     

改性酚醛环氧树脂及潜伏性固砂剂在油井固砂中的应用

以2-苯基咪唑(2PZ)为芯材、聚苯乙烯(PS)为壁材,采用溶剂挥发法制备了2PZ/PS微胶囊固化剂;然后将其添加到硅烷偶联剂(KH-550)改性的PF/EP(酚醛环氧树脂)中,制得单组分潜伏性固砂剂。研究结果表明:2PZ/PS微胶囊中w(2PZ)≈35%;该微胶囊固化剂具有表面光滑、粒径分布较窄等特点;与常规PF/EP相比,当w(KH-550)=8%(相对于PF/EP质量而言)时,制得的固砂剂具有相对更低的固化温度,并且潜伏性能良好(室温储存期40 d),由其制备的固结岩心之压缩强度(为10.5 MPa)相对最大且耐介质性能优异。     

环氧复合材料低温固化剂研究进展

低温固化(固化温度低于100℃)可获得高尺寸稳定性、低成本、力学性能优良的环氧复合材料,室温储存期长的低温固化剂体系是低温固化环氧复合材料的关键。重点探讨了微胶囊型、潜伏性以及其它改性环氧低温固化剂,展望了其未来前景及发展方向。     

单组分环氧胶粘剂用固化剂

日本味之素精细化学株式会社制造的单组分环氧胶粘(AH-154、AH-162)、二酰肼(VDH、UDH)、叔胺缩合物(MY的良好促进剂。剂用固化剂有咪唑加成物(PN-23、PN-31、PN-40)、双氰胺改性物24)，能使环氧树脂在较低温度下快速固化。还能用作酸酐固化剂     

一种新型环氧树脂潜伏性固化剂二苯基双胍的合成与性能

设计并合成了一种环氧树脂潜伏性固化剂二苯基双胍。采用FTIR和1HNMR表征了固化剂的化学结构,并通过DSC分析得到环氧树脂与固化剂的最佳质量配比为5∶1,固化活性实验及凝胶实验分析得到最佳固化温度为130℃,储存期为室温下30 d,拉伸实验分析了固化物的抗拉强度可达38.07 MPa,采用TG测试得到固化物的热分解温度超过270℃。结果表明,与双氰胺环氧树脂固化体系相比,该固化剂和环氧树脂有更好的相容性,潜伏性良好,其固化温度降低30℃以上,固化物有更优异的力学性能和良好的热稳定性。     

潜伏性环氧树脂胶粘剂用液态改性双氰胺固化剂的研究

以环氧丙烷-甲醛作为改性剂,合成了一种潜伏性EP胶粘剂用液态改性DCA(双氰胺)固化剂;然后以改性前后的DCA分别作为EP的固化剂,采用红外光谱(FT-IR)法、差示扫描量热(DSC)法和凝胶时间测定法等探讨了不同固化剂对EP胶粘剂性能的影响。结果表明:当体系的pH为9、固化工艺为"80℃/10min→130℃/60min"时,液态改性DCA对EP具有较高的反应活性,相应的单组分EP胶粘剂具有相对较好的综合性能,其固化温度降低了30℃左右且无黄变现象,并且其室温时有2个月左右的储存期、-5℃时有半年以上的储存期。     

酒石酸改性咪唑制备工艺及性能研究

用硬度表征涂膜固化性能,研究了酒石酸改性咪唑的制备工艺对改性咪唑固化性能的影响。结果表明,酒石酸改性咪唑的较佳制备工艺为:酒石酸与咪唑的物质的量比为1:0.45,于80℃反应1 h。酒石酸改性咪唑可使双氰胺固化环氧树脂的固化温度降至120℃,固化2 h,硬度为4 H。酒石酸改性咪唑单独作为固化剂或作为双氰胺固化促进剂,与咪唑相比,其潜伏性均有大幅度提高。     

水杨酸改性咪唑环氧树脂固化促进剂的合成与性能研究

研究了水杨酸改性咪唑的制备方法及工艺,对改性咪唑固化性能的影响,用涂膜硬度表征固化性能。结果表明,水杨酸改性咪唑的较佳制备工艺为水杨酸与咪唑的物质的量比为1:1,研磨混合均匀,室温放置1 h。水杨酸改性咪唑可使双氰胺的固化温度降至140℃,固化240 min,硬度为4H。水杨酸改性咪唑与咪唑作为双氰胺固化促进剂相比,其潜伏性有大幅度提高,耐热性亦比咪唑高。     

α-羟基-2-萘甲酸对热固性有机硅改性酚醛树脂性能的影响

研究了α-羟基2-萘甲酸作为热固性有机硅改性酚醛树脂固化促进剂,对其固化温度、粘接性能、耐热性能和贮存性能的影响。表明α-羟基2-萘甲酸作为杂环有机弱酸,在有机硅改性酚醛树脂固化过程中产生H+,以及有机杂环的封端作用,可使热固性有机硅改性酚醛树脂的固化温度下降,粘接性能和耐热性能均有提高,而且还具有一定的贮存期。     

Preparation and curing behavior of latent 2-PhIm-PS microcapsule curing agent for epoxy resin

A core–shell microcapsule latent epoxy curing agent (2-PhIm-PS) is obtained by solvent evaporation method with 2-phenyl imidazole (2-PhIm) as the core material and polystyrene (PS) as the wall material. The microcapsule parameters, morphology, structure, curing behavior, and the mechanic properties of cured epoxy resin with this microcapsule latent curing agent were characterized through comparing with 2-PhIm. The particle size distribution of the microcapsule is narrow, the average particle size is about 10.56 μm, and the core material content is 23%. The prepared 2-PhIm-PS microcapsule curing agent has excellent latent curing properties. It can completely cure epoxy resin E-51 within 10 min at 130°C, and its latent period can be more than 40 days at room temperature. In addition, the curing kinetics of one-component epoxy resin curing system (E-51/2-PhIm-PS) composed of 2-PhIm-PS microcapsules and epoxy resin E-51 is also studied by using Kissinger equation, Flynn–Wall–Ozawa and Crane formula. The results provide an outline for the evaluation on the applicability of the microcapsule curing agent of 2-PhIm-PS for epoxy resin.     

有机酸改性咪唑环氧树脂固化促进剂的研究

二氰二胺作为环氧树脂的潜伏性固化剂,其固化物机械性能和介电性能优异。但由于二氰二胺与环氧树脂相溶性差,得不到均匀的组成物,且环氧树脂/二氰二胺体系的固化过程需在高于160℃的温度中进行。利用不同含量的有机酸与咪唑3位氮原子中和,改性生成的盐作为环氧树脂/二氰二胺体系固化促进剂,对该体系进行了改进,使其能够在中温(90～120℃)条件下固化。利用IR对改性产物进行了表征,并对未加促进剂的环氧树脂/双氰胺体系和以咪唑及有机酸改性咪唑为促进剂三种体系分别进行了差热分析。结果表明,有机酸改性咪唑促进剂可以使环氧树脂/二氰二胺体系的固化温度降低近50℃,并且适用期显著增加,长达141d,耐水性和耐热老化性能增加。     

Preparation of imidazole embedded polyurea microcapsule for latent curing agent

The IZ-PU microcapsule-type curing agent was prepared by interfacial polymerization method. The shell-core structure of the IZ-PU microcapsules was demonstrated by IR and SEM. The core content and coating efficiency of the IZ-PU microcapsules were analyzed by DSC test of the one-component adhesive consisting of IZ-PU microcapsules and epoxy resin. The results showed that the IZ-PU microcapsules is a proper latent curing agent to epoxy resin, its latency at room temperature is longer than 30 days.     

Polyamine microcapsules featured with high storage stability used for one-component epoxy adhesive

One-component epoxy adhesives have great promising prospects in industrial applications. However, it faces the challenge to reduce the activity of curing agents for achieving long-term storage and controlled release. Microencapsulation is a feasible and effective solution. In this paper, multi-polyaniline (MPAN) was successfully encapsulated with polyetherimide (PEI), a thermoplastic resin, as the shell material by using solvent evaporation method with dichloromethane (DCM) as solvent. The impacts of different preparation parameters on the structure and properties of microcapsules were investigated by single variable control method. It is found that the resulted microcapsules under the optimal process parameters, namely PVA concentration 1 wt%, core/shell mass ratio 1:1 and stirring rate 700 rpm, exhibits a smooth and dense spherical surface with an average particle size concentrated around 17.8 μm. Compared with the pure curing agent, the encapsulated curing agent effectively prolonged the shelf life of the epoxy adhesive at 40°C for at least 60 days, indicating excellent storage stability. The microencapsulated MPAN curing agent prepared in our research is of potential applications in the fields of electronic component bonding, potting and circuit board sealing due to its high storage stability and encapsulation efficiency (74%).     

Microencapsulation of imidazole curing agent by solvent evaporation method using W/O/W emulsion

The epoxy–imidazole resin system is used to form the anisotropic conducting film. The latent character of the system is very significant. In this study, imidazole (Im) or 2‐methylimidazole (2MI) was encapsulated for the latent curing system to use in the reaction of epoxy resin. Polycaprolactone was used as a wall material, and the solvent evaporation method was used to form the microcapsule using W/O/W emulsion. The shelf life of the microcapsules was studied for the epoxy resin, and the curing behavior of the microcapsules for epoxy resin was examined using a differential scanning calorimeter. The curing times at 150 and 180°C were estimated using an indentation method. The microcapsules of Im or 2MI exhibited a long shelf life for epoxy resin. When comparing the results of the previous methods with the results of this study using the W/O/W emulsion, finer microcapsules were formed and the microcapsule has longer shelf life. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

环氧树脂微胶囊与潜伏性固化剂自修复体系断裂韧性的研究

微胶囊二元自修复系统对聚合物基复合材料在使用中产生的微小裂纹具有修复作用,但微胶囊和固化剂的加入会对基体材料的断裂韧性产生影响。本文研究了环氧树脂微胶囊和咪唑类潜伏性固化剂对聚合物基复合材料基体材料的断裂韧性的影响。采用环氧树脂E-51作为基体材料,三乙烯四胺为常温固化剂,咪唑类衍生物2MZ-Azine和实验室自制的包含环氧树脂芯材的微胶囊为材料制作断裂韧性拉伸试样。实验结果表明,当微胶囊的含量达到一定比例之前,基体材料的断裂韧性随着微胶囊含量的增加而增强,当微胶囊含量超过此比例后,基体材料的断裂韧性随着微胶囊含量的增加而减小,潜伏性固化剂的加入会增大基体材料的断裂韧性。这与环氧树脂材料增韧理论相符合。     

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