阳离子引发剂在环氧树脂固化体系中的应用研究

讨论了阳离子引发剂催化环氧树脂固化体系反应的原理,综述了新型阳离子引发剂,即镧系金属氟化物在DGEBA、DGEBA/γ-BL、DGEBA/MCB、DGEBA/MA、DGEBA/PC体系中的作用。浅析了固化促进剂的选用原则,并对镧系金属氟化物在环氧树脂/聚酰胺中的应用前景作了展望。     

紫外光固化环氧丙烯酸酯涂料的制备研究

为解决环氧丙烯酸酯黏度较大这一问题,以低黏度的γ-缩水甘油醚氧丙基三甲氧基硅烷(A187)代替环氧树脂,讨论了环氧丙烯酸酯合成中A187与丙烯酸的配比、催化剂、反应温度和阻聚剂对反应的影响,研究了光引发剂含量对UV涂膜性能的影响。确定了该紫外光固化涂料的工艺。     

Electron-beam curing of epoxy resins: Effect of alcohols on cationic polymerization

Electron-beam (e-beam) induced polymerization of epoxy resins proceeds via cationic mechanism in presence of suitable photoinitiator. Despite good thermal properties and significant processing advantages, epoxy-based composites manufactured using e-beam curing suffer from low compressive strength, poor interlaminar shear strength, and low fracture toughness. A detailed understanding of the reaction mechanism involving e-beam induced polymerization is required to properly address the shortcomings associated with e-beam curable resin systems. This work investigated the effect of hydroxyl containing materials on the reaction mechanism of e-beam induced cationic polymerization of phenyl glycidyl ether (PGE). The alcohols were found to play important roles in polymerization. Compared to hydroxyl group of aliphatic alcohol, phenolic hydroxyl group is significantly less reactive with the oxonium active centre, generated during e-beam induced polymerization of epoxy resin system.     

碳纳米管/环氧丙烯酸酯紫外光固化涂层的制备及光阻隔性能

利用碳纳米管(CNTs)表面官能团与环氧丙烯酸酯(EA)齐聚物的反应, 制备了碳纳米管/环氧丙烯酸酯(CNTs/EA)光敏性树脂, 通过紫外光(UV)固化交联制备出新型复合涂层。研究了涂层的阻隔红外/紫外线性能, 在近红外区(4000~12000 cm-1)的阻隔率为68.55%, 对可见光(380~780 nm)的透过率大于85％, 对于＜300 nm的紫外线完全阻隔。同时复合涂层力学性能与EA涂层相比也得到提高, 在光阻隔涂层方面具有潜在的应用前景。      

Effects of time,temperature and curing on the stiffness of epoxy laminating systems

Relative creep moduli of a series of epoxy laminating resins were found to be the same in uniaxial tension and in torsion when measured under loads of short duration. However, their tensile creep moduli decreased with time and temperature at different rates, changing their relative stiffness. For one typical resin the short-term tensile and shear moduli decreased with cure temperature reaching minima and then increased slightly. Deflection temperature under load determined by standard tests correlated inversely with the short-term tensile modulus for the typical resin considered and failed to provide a basis for determining the relative stiffness of the different resin systems.     

Combinatory model of curing process in epoxy composite

A combinatory model of curing process in a mixture of multifunctional active components was developed. The model was tested with an analysis of curing kinetics in epoxy resin based on Bisphenol A with amine hardener. The experimental kinetics data obtained with FTIR and Raman spectroscopy, chromatography and viscosimetry methods were applied. The theoretical results show good agreement with experiment. The model can predict a concentration of middle products during curing reaction. The model is developed for calculation of the curing kinetics in free space environment.     

快速固化环氧树脂及其碳纤维/环氧复合材料性能

采用双酚A型环氧树脂（DGEBA）、改性咪唑（MIM）及改性脂肪胺（MAA）研制快速固化树脂体系。分别利用DSC和流变仪测试了树脂体系的固化特性与流变行为,优选了树脂配方。采用真空辅助树脂灌注工艺（VARIM）制备了快速成型的碳纤维/环氧复合材料层板,考察了层板的成型质量和力学性能,并与常规固化的层板性能进行了对比。结果表明：采用优选的树脂配方,120 ℃下树脂在5 min内固化度达95%,碳纤维/环氧复合材料层板成型固化时间可控制在13 min以内,固化度达95%以上,并且没有明显缺陷;与常规固化相比（固化时间大于2 h）,快速固化碳纤维/环氧复合材料层板的弯曲性能和耐热性能降低幅度较小。     

Optical and mechanical properties of jet printed and UV cured blue pixels with phosphated epoxy acrylate as the curing agent

Phosphated epoxy acrylate and phosphated imide-epoxy were synthesized and used as compositions of non-volatile (no solvent) UV curable ink for manufacturing the jet-printed LCD color filter (CF). Phosphated epoxy acrylate oligomer showed not only good solubility in UV curable monomers and pigment compatibility as ink compositions, but also good thermal and mechanical properties after curing. No receiver layer or barrier ribs are necessary to prevent the printed ink from overflowing to the neighboring area. The color inks were precisely ejected to the glass substrate and UV-cured immediately to make the stripe pattern. The printed blue stripes exhibited smooth surface, straight edge, high transparency (transmittance > 84%), high nanoindentation hardness (3.94 GPa) and modulus (72.15 GPa). The influences of curable compositions on the optical properties, patterning properties, surface morphology and nanoindentation hardness of the micro-stripes were discussed.     

Characterization of epoxy functionalized graphite nanoparticles and the physical properties of epoxy matrix nanocomposites

This work presents a novel approach to the functionalization of graphite nanoparticles. The technique provides a mechanism for covalent bonding between the filler and matrix, with minimal disruption to the sp² hybridization of the pristine graphene sheet. Functionalization proceeded by covalently bonding an epoxy monomer to the surface of expanded graphite, via a coupling agent, such that the epoxy concentration was measured as approximately 4 wt.%. The impact of dispersing this material into an epoxy resin was evaluated with respect to the mechanical properties and electrical conductivity of the graphite–epoxy nanocomposite. At a loading as low as 0.5 wt.%, the electrical conductivity was increased by five orders of magnitude relative to the base resin. The material yield strength was increased by 30% and Young’s modulus by 50%. These results were realized without compromise to the resin toughness.     

E 51环氧树脂固化反应中动力学转变

采用等温DSC法研究了E-51环氧树脂与4, 4’-二氨基二苯基砜(DDS)体系的固化反应过程, 并与已有固化模型拟合得到了170、180、190、200 ℃下的等温固化反应动力学的参数, 根据决定系数R2确定了适合的固化模型。研究表明: 当固化度小于40%时属于Kamal自催化模型; 当固化度大于40%时属于n级固化模型, 即固化反应由Kamal自催化反应向n级反应转变。      

Study of the infrared spectral features of an epoxy curing mechanism

In this work, the isothermal curing process of diglycidyl ether of bisphenol A (DGEBA) cured with 4,4'-diaminodiphenylmethane (DDM) was monitored in situ by mid-infrared (MIR) and near-infrared (NIR) spectroscopy. With the help of generalized two-dimensional (2D) correlation analysis, the results obtained showed that, during curing, the change of amine and epoxy groups was simultaneous, taking place prior to the change of hydroxyl groups, followed by the change of CH(2)/CH groups, resulting from the ring-opening reaction of epoxy groups. In addition, 2D MIRxNIR hetero-spectral correlation analysis and second-derivative analysis were also employed, by means of which direct evidence of the curing mechanism could be obtained and obscure NIR band assignments in the overlapped CH combination region could be made.     

Surface migration of fluorinated additive during the curing of epoxy resin

Driving forces, responsible for the migration of a fluorinated additive added to a thermoset resin, toward the air/solid interface, were investigated. On this subject, the surface chemistry as characterized by XPS analyses was compared to theoretical models based on the rheological properties of the blend. It appears that the migration of the fluorinated molecules toward the surface cannot be described by a conventional diffusion model. A second model derived from the latter suits better to the experimental data and should be presented as another proof that additional motion forces drive the fluorine molecules migration in curing epoxy resin.     

超声波法在线监测端羟基聚丁二烯/甲苯二异氰酸酯体系的固化过程

采用超声波纵波透射法在线监测了端羟基聚丁二烯/甲苯二异氰酸酯（HTPB/TDI）体系在不同温度下的固化过程,测定了固化过程中超声波的声速与衰减,计算了体系的纵向储能模量和固化度,由此确定了体系的凝胶化、硬化以及固化终点时间。与红外光谱法相比,超声波法通过表征固化体系模量的变化更合理地揭示了体系物理交联和化学交联两方面协同作用的固化机理,对HTPB/TDI体系硬化后的固化过程监测更为灵敏。     

Investigation of the microwave curing of the PR500 epoxy resin system

Microwave heating has been used to cure a resin system, PR500 (3M). The same resin has been cured using a conventional oven. The cured resins have been compared using a number of techniques including modulated differential scanning calorimetry (MDSC), dynamic thermal analysis, infrared spectroscopy (IR) and solid-state NMR spectroscopy. The reaction path appears to be slightly different depending upon the nature of the heating. The epoxy-amine reaction occurs to a greater extent than the epoxy-hydroxyl reaction in the microwave cured resin compared to the thermally cured resin. The dielectric properties for the thermally and microwave cured materials were measured for degrees of cure greater than 75% and over this range are similar for materials cured by the two techniques and thus not sensitive to this change. Broadening of the glass transition for microwave-cured epoxy resins was observed. Since the IR and solid-state NMR results show small differences as does the DMA behaviour of materials cured using the two routes the broadening is attributed to a difference in network structure.     

UV固化用丙烯酸单体、预聚物的进展

就ＵＶ固化用树脂的单体和预聚物及其合成方法、种类、用途、性能要求等问题作了说明，并介绍了丙烯酸系单体对皮肤的一次性刺激问题和改良方法，以及新型的单体和预聚物。     

超声波在线监测环氧树脂固化反应过程

采用超声波技术成功地对环氧树脂固化过程进行了在线监测。超声波横渡与纵波及其波峰衰减反映了固化体系剪切模量的变化、凝胶点和固化终点。固化剂含量为9％时有利于体系的完全固化。超声波法在线监测技术将为研究聚合物固化反应提供了一种简单、实用的技术手段。