反应型环氧树脂固化剂的研究现状与发展趋势

环氧树脂是应用广泛的热塑性高分子预聚物,只有加入固化剂后方能显示出优异的性能,因此固化剂对于环氧树脂的应用及对固化产物的性能发挥着巨大的作用。在环氧树脂固化剂中,又以反应型固化剂的固化效果比较优异且使用方便,品种众多。综述了反应型环氧树脂的固化剂的种类及反应机理,介绍了近年来国内外几种性能优异的反应型环氧树脂固化剂,其中包括多元胺类固化剂、酸酐类固化剂、多元硫醇类固化剂、咪唑类固化剂等,指出其发展趋势是环保型、耐高温、高强度、高耐久性及快速固化。     

次中温环氧树脂固化剂(8104)的性能研究

本文研究了一种次中温环氧树脂固化剂（８１０４）的工艺性及其固化物的性能。试验结果表明：８１０４固化剂可在５０－８０℃下固化环氧树脂;与环氧树脂的混合物在室温下的适用期大于１０ 小时;固化物具有极好的韧性、良好的耐湿热性能和力学性能。因此,８１０４可用于大面积和大体积的环氧树脂固化施工,也可作为模具树脂、涂料及结构材料的固化剂。     

E-44型环氧树脂固化和应用的研究

主要研究了金属导电浆料中常用的环氧树脂的固化。实验选用了常用的几种多乙烯多胺类及乙醇胺类固化剂,研究了固化剂用量,固化温度对E-44型环氧树脂固化的影响。实验结果表明其固化时间均随固化剂用量的增加和固化温度的升高而缩短,且固化产物性能提高。当以二乙烯三胺、三乙烯四胺、四乙烯五胺为固化剂,固化剂用量为环氧树脂量的13％左右,固化温度为75℃或115℃,所需固化时间短,在30min左右,固化产物性能良好。以乙醇胺和三乙醇胺为固化剂,固化剂用量约为环氧树脂用量的16％,固化温度为115℃,固化时间约 2．5h,所得固化产物性能良好。应用该固化条件,所制备的铜导电浆料导电性能良好,电阻率≤4．7×10-3Ω·cm。     

NH-POSS基耐高温环氧树脂的制备及动力学分析

环氧树脂耐高温基体在航空航天、特种涂料、电气及半导体电子等高新技术领域得到了广泛的应用。环氧树脂的性能在很大程度上受环氧树脂固化剂的影响,对比了三种不同胺固化剂对环氧树脂固化的影响,结果显示实验室自制的NH-POSS固化剂优于脂肪族和芳香族类胺固化剂,NH-POSS固化剂可以提高整个固化体系的耐高温性能,使其玻璃化转变温度高达234℃,是一种耐高温树脂。采用n级反应理论的动力学模型,并对热力学数据进行分析,拟合出了NH-POSS环氧树脂体系的固化工艺条件,为NH-POSS固化环氧树脂的加工工艺提供了理论依据。     

聚双胍/环氧树脂体系潜伏性固化过程

用己二胺与双氰胺熔融缩聚, 合成了一种新型潜伏性环氧树脂固化剂, 并研究了其与环氧树脂的固化过程。用FTIR、XPS、¹H NMR分析了固化剂的结构;用DSC分析得到了固化剂与环氧树脂的适宜配比、固化体系的适宜固化温度及固化动力学参数;通过XRD分析了固化物的相结构;通过TG分析了固化物的热稳定性。结果表明, 与双氰胺环氧树脂固化体系相比, 固化温度降低近70℃, 同时潜伏性能良好, 30 d内固化度少于10%, 热稳定性能良好, 热分解温度超过300℃。     

腰果酚改性环氧树脂固化剂的研究进展

介绍了国内外腰果酚改性环氧树脂固化剂的研究现状,包括腰果酚改性环氧固化剂的合成、表征、固化物的固化速率及硬度、韧性、固化物的力学性能和其他性能,并指出了腰果酚改性环氧树脂固化剂的发展方向。     

试析不同芳香胺固化剂与环氧树脂的固化性能

在精细化工中,经常使用的固化剂为芳香胺和环氧树脂,环氧树脂固化剂的具有良好的固化性能,粘合性较强,具有非常高的强度、耐热性、稳定性等性能,芳香胺固化剂的固化性能也相对的较好,为了更好的认识不同芳香胺固化剂和环氧树脂固化剂的固化性能,本文对其进行实验分析。     

水性环氧树脂防腐清漆的制备与性能

以自制非离子水性环氧固化剂与环氧树脂混合制备水性环氧树脂防腐清漆,探讨了封端剂种类、水性环氧固化剂与环氧树脂配比、固化温度对漆膜性能的影响,结果表明最佳封端剂为苯基缩水甘油醚(PEG);最佳水性环氧固化剂与环氧树脂配比为环氧/胺氢当量比为1.1;漆膜室温下即可固化,防腐性能优秀。     

环氧树脂固化技术及其固化剂研究进展

综述了近年来国内外关于环氧树脂的热固化、微波固化及光固化技术的研究情况。在热固化技术领域 ,着重介绍了具有高耐热性、阻燃性、韧性等性能的几种功能性固化剂以及几种新型改性胺类固化剂 ;通过与热固化的对比 ,对环氧树脂的微波固化体系进行了初步的分析与探讨 ;在光固化技术领域则主要概述了环氧树脂的阳离子紫外光固化体系与自由基 -阴离子混杂光固化体系的进展情况     

水性环氧树脂涂料及其固化机理的研究

通过对环氧树脂室温固化剂三乙烯四胺进行封端、加成、成盐等一系列改性,制得自乳化水性环氧树脂固化剂;与低相对分子质量的液体环氧树脂混合后,获得了水性环氧树脂涂料。研究了不同封端剂对固化剂乳化性能的影响以及与环氧树脂配成涂料后对涂膜性能的影响,并通过对固化成膜过程的观察,阐述了水性环氧体系固化机理。获得的涂料乳液粒径小于2μm;涂膜硬度>0.7;附着力1级;涂膜具有良好的透明性、耐水性及耐化学药品性。     

Aminimide as hardener/curing promotor for one part epoxy resin composition

Three kinds of aminimide compounds were examined as latent hardeners/promotors for epoxy resins. Since aminimides are thermolyzed to generate tertiary amine and isocyanate, the compounds are useful as polymerization initiators for the epoxy group as well as promotors for epoxy–acid anhydride reaction. The pot life was over 30 days at 40°C for a formulated one-part epoxy resin system. In comparison with epoxy resins cured with conventional hardeners, several interesting characteristics of the mechanical and electrical properties were observed. In particular, the epoxy resins cured by aminimides exhibited high tensile strength and high impact strength, which make them excellent curing agents for adhesive applications. The reasons for these unique properties are discussed.     

Epoxy resin from cardanol as partial replacement of bisphenol-A-based epoxy for coating application

With continuous depletion of petrochemical feedstock and their rising prices, the chemical industry is now looking for alternative renewable and sustainable materials. Such materials could be processed with various chemistries to produce high performance functional materials for a range of applications, such as plastics, coatings, constructions, pharmaceuticals, and food applications. Cardanol derived from cashew nut shell liquid has a reactive phenolic group and aliphatic double bond that could be exploited to produce novel functional materials for polymer and coating applications. It has previously been used for preparation of phenolics, epoxy, and phenalkamine hardeners. In this study, we report on the preparation of novel epoxy resin from cardanol via simple a two-step reaction. The prepared resin with epoxy equivalent weight of 210–220 gm/eq was analyzed using FTIR and NMR spectroscopy. The epoxy resin was then used as binder along with bisphenol-A-based epoxy resin (DGEBPA) at various weight proportions and cured with different amine hardeners. The cured coatings were analyzed for physical, mechanical, and chemical properties for optimization of the coating formulation. The study conducted showed that 40–60% of DGEBPA resulted in comparable properties to that of completely DGEBPA-based system. Further, thermal and anticorrosive properties of the optimized coatings were also evaluated.     

Epoxy resin modified with soybean oil containing cyclic carbonate groups

Carbonated soybean oil (CSO) containing five‐membered cyclic carbonate groups has been obtained in the reaction of epoxidized soybean oil with carbon dioxide in the presence of KI activated by 18‐crown‐6 under 6 MPa CO₂ pressure at 130°C. The CSO was used for modification of bisphenol‐A based epoxy resin. The composition epoxide‐cyclic carbonate was cured using polyamine hardeners by one‐step and two‐step procedures. All cured compositions were characterized for their thermal and mechanical properties and compared with the parent epoxy network. The optimal properties were obtained for compositions containing CSO and cured by one‐step method when phase separation takes place. The mechanical properties were discussed in terms of morphology observed by SEM. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2904‐2914, 2006     

Synthesis of a Sustainable and Bisphenol A-Free Epoxy Resin Based on Sorbic Acid and Characterization of the Cured Thermoset

In the present study, an epoxy compound, 1,2-epoxy-6-methyl-triglycidyl-3,4,5-cyclohexanetricarboxylate (EGCHC) synthesized from sorbic acid, maleic anhydride, and allyl alcohol is proposed. Using commodity chemicals, a bio-based carbon content of 68.4 % for the EGCHC resin is achieved. When cured with amine hardeners, the high oxirane content of EGCHC forms stiff cross-linked networks with strong mechanical and thermal properties. The characterization of the epoxy specimens showed that EGCHC can compete with conventional epoxy resins such as DGEBA. A maximum stiffness of 3965 MPa, tensile strength of 76 MPa, and T_g of 130 °C can be obtained by curing EGCHC with isophorone diamine (IPD). The cured resin showed to be decomposable under mild conditions due to the ester bonds. The solid material properties of EGCHC expose its potential as a promising bisphenol A, and epichlorohydrine free alternative to conventional petroleum-based epoxies with an overall high bio-based carbon content.     

The influence of the molecular structure on the chemical resistivity of solventless and high-solid epoxy resins

The chemical resistance of solventless and high-solid epoxy compositions has been studied. The compositions have been cured at normal temperature and the chemical resistivity has been studied as a function of various resin types, solvent types and hardener types. The chemical resistance increases slightly with increasing epoxy equivalent weight. This is especially pronounced for this type of dependence relative to low molecular weight organic acids. The resistance of diluents to hydrolysis is more important than the reactivity of the diluent used. Also the capacity to swell plays an important role for a given solvent and resin system. The highest resistances have been determined for styrene as a reactive diluent and for 1,1-diphenylethane as the non-reactive diluent. The differences due to polyamine hardeners are decreased with the use of epoxy resin of higher epoxy equivalent weight.     

Preparation and characterization of thermally stable epoxy-titanate coatings

Epoxy-polyamide coatings are used to protect metallic substrates in corrosive atmosphere. Thermal stability of the coating can be improved by the addition of inorganic cross-linking agent. Epoxy resin is incorporated with small percentage of silicone resin and cured with two types of hardeners such as polyamide and butyl titanate. The physical properties, heat resistance properties and electrochemical impedance behaviour of these coatings on steel in 0.5 M NaCl solution have been studied. The result implies that the heat resistant character of the titanate-cured coating is increased from 260 to 370 °C. The impedance study has shown that the coating resistance exerted by both the systems is in the range of 10⁵ Ω cm² after 6 days of immersion in 0.5 M NaCl. FTIR and Raman spectroscopy analysis confirm the presence of titanate linkage in the cured polymer coating. Thermal stability data indicate that the epoxy silicone resin cured with titanate hardener possesses higher thermal stability than that cured by polyamide hardener.     

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。     

Novel phosphorus‐containing hardeners with tailored chemical structures for epoxy resins: Synthesis and cured resin properties

A comparative evaluation of systematically tailored chemical structures of various phosphorus‐containing aminic hardeners for epoxy resins was carried out. In particular, the effect of the oxidation state of the phosphorus in the hardener molecule on the curing behavior, the mechanical, thermomechanical, and hot‐wet properties of a cured bifunctional bisphenol‐A based thermoset is discussed. Particular attention is paid to the comparative pyrolysis of neat cured epoxy resins containing phosphine oxide, phosphinate, phosphonate, and phosphate (with a phosphorus content of about 2.6 wt %) and of the fire behavior of their corresponding carbon fiber‐reinforced composites. Comparatively faster curing thermosetting system with an enhanced flame retardancy and adequate processing behavior can be formulated by taking advantage of the higher reactivity of the phosphorus‐modified hardeners. For example, a combination of the high reactivity and of induced secondary crosslinking reactions leads to a comparatively high T_g when curing the epoxy using a substoichiometric amount of the phosphinate‐based hardener. The overall mechanical performance of the materials cured with the phosphorus‐containing hardeners is comparable to that of a 4,4′‐DDS‐cured reference system. While the various phosphorus‐containing hardeners in general provide the epoxy‐based matrix with enhanced flame retardancy properties, it is the flame inhibition in the gas phase especially that determines the improvement in fire retardancy of carbon fiber‐reinforced composites. In summary, the present study provides an important contribution towards developing a better understanding of the potential use of such phosphorus‐containing compounds to provide the composite matrix with sufficient flame retardancy while simultaneously maintaining its overall mechanical performance on a suitable level. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

胺化酰亚胺固化的环氧树脂体系的特性及其固化机理

能热分解成异氰酸酯和叔胺的胺化酰亚胺是很好的潜伏性环氧树脂固化剂和环氧-酸酐体系的固化促进剂,它固化的环氧树脂有许多优异的性能,特别是高的韧性和粘接强度。由胺化酰亚胺热分解速度控制的、高温下相对慢的、独待的固化机理是韧性的起因。     

新型环氧树脂灌封材料的研究

研究了环氧树脂灌封材料中,羟基化合物对固化物性能的影响。羟基化合物和环氧基发生扩链反应,降低了固化物的交联度;冲击强度达到25kJ/m~2以上,电性能也得到一定的改善,是较理想的F级灌封材料。