双氰胺/环氧粉末涂料的研究

以E-12环氧树脂为基础树脂、双氰胺(Dicy)为固化剂、2-甲基咪唑(2-MI)为促进剂,并配以其他助剂,经熔融共混制备出双氰胺/环氧粉末涂料。考察双氰胺、2-甲基咪唑用量对固化反应、涂膜附着力及耐冲击性的影响,并确定了两者的较佳用量。利用非等温差示扫描量热法研究了环氧/双氰胺/2-甲基咪唑体系的固化反应,并通过动力学分析得出了理论固化温度等固化动力学参数。在此基础上,根据实验得到了较好的固化时间和固化温度。另外,根据Kissinger和Crane方程拟合了固化反应动力学方程。结果表明,涂膜附着力及耐冲击性随着双氰胺及2-甲基咪唑用量增加先提高后减小。双氰胺、2-甲基咪唑用量分别为环氧树脂用量的4.00%、0.40%时,体系固化温度较低,130.00°C下固化30 min所得涂膜综合性能最好。     

双模板分子印迹聚合物在奶粉检验中的应用研究

采用本体聚合法制备三聚氰胺(MEL)与双氰胺(DCD)双模板分子印迹聚合物(MEL/DCD-MIPs),将其作为固相萃取介质,实现了奶粉中MEL与DCD富集与纯化,建立了奶粉中两种物质同时检测的方法。通过热力学、选择性和动态结合试验表明,与单模板分子印迹聚合物相比,双模板分子印迹聚合物由于双模板-功能单体分子间的多位点协同作用而有更好的印迹效应,对MEL和DCD结合能力高于结构类似物三聚氰酸(CYA)。固相萃取试验显示,MEL/DCD-MIPs可以从市售奶粉中选择性地分离、富集MEL与DCD,对MEL与DCD的加样回收率分别为93.1%~100.1%和75.7%~82.5%,RSD均小于5.2%。所制得的MEL/DCD-MIPs可应用于奶粉等食品中氰胺类物质的检测。     

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℃。     

絮凝—吸附工艺联合处理1,2,4-酸废水

研究6-硝生产过程中产生的1,2,4-酸废水的处理工艺.采用絮凝和吸附手段处理1,2,4-酸废水,絮凝试验采用自制的双氰胺-甲醛聚合物为絮凝剂的絮凝体系;吸附试验采用自制的AEO-9改性的膨润土作为吸附剂.试验结果表明,以双氰胺-甲醛絮凝剂絮凝处理废水的最佳条件为:废水的pH=3,絮凝剂用量为1％,在70℃的水浴锅中快...     

邻、间、对双胍基苯甲酸盐酸盐的制备及其结构表征

以邻、间、对氨基苯甲酸为起始原料,在盐酸存在下分别与双氰胺一步合成了中间体邻、间、对双胍基苯甲酸盐酸盐.采用红外光谱、紫外光谱、核磁共振氢谱对目标产物进行了结构表征.     

Zinc Coated Steel/Epoxy Adhesive Systems: Investigation of the Interfacial Zone by FTIR Spectroscopy

The present study takes advantage of the ability of Fourier Transform Infrared Spectroscopy (FTIR) for the analysis of ultrathin organic films on metals. FTIR in the reflection mode (IRRAS) is used in order to study the interaction of ultrathin films of dicyandiamide (hardener of most one-pack epoxy resins) with various substrates, model ones such as gold or zinc and industrial ones such as steel and zinc-coated steels.

Pure zinc surfaces and, to a lesser extent, zinc-coated steels are shown to react with dicyandiamide after heating at 180°C, as evidenced by the frequency shift of the absorption band (at about 2200 cm^-1) characteristic for nitrile groups. As real systems consist of thick layers of a fully formulated adhesive cured onto a metallic substrate, the direct investigation of such a buried interphase is no longer possible by FTIR and by most of the known spectroscopies. Some mechanically tested specimens are then analysed, after failure, by FTIR microspectrometry. The spectra obtained, corresponding to the fracture initiation zone which is about 100 μm in diameter, advocate for the presence of an ultrathin layer of modified polymer still covering the substrate.     

The synergistic effect of dicyandiamide and resorcinol in the curing of epoxy resins

The synergistic effect of dicyandiamide (Dicy) and phenolic substances was studied, with resorcinol as a model compound. It was found that when Dicy and resorcinol are used jointly, the curing temperature of epoxy resin can be significantly lowered. FTIR and DSC data were used to illustrate the mechanism of the synergism. The addition of the phenolic hydroxyl group to epoxide was facilitated by Dicy, which favors the formation of phenoxy anions. The reaction of Dicy with epoxide was facilitated by resorcinol, which can exert “electrophilic assistance” for the addition of the amino group to epoxide. The presence of resorcinol also favors the addition of the hydroxyl group to the cyano group. The thermal and mechanical properties of the epoxy resins cured with Dicy/resorcinol or Dicy/phloroglucinol were studied. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1869–1874, 2003     

DSC及IR联合测定环氧树脂-双氰胺体系固化工艺参数

采用非等温DSC法研究了固化剂用量对环氧树脂固化反应的影响。同时利用不同升温速率下测得的DSC曲线研究了环氧树脂-双氰胺体系的固化反应动力学,并由DSC及IR分析技术确定了该体系的最佳反应条件。实验结果表明：固化剂双氰胺最佳用量为5．6％,最佳固化温度为403K,固化时间为70min,该体系的反应活化能为96．82kJ／mol,反应级数为0．93。     

水解连续化新工艺在双氰胺生产中的应用

针对国内间歇式水解和过滤工艺技术落后的局面，我厂经反复试验实现了水解连续化生产双氰胺的新工艺，从而使各项技术指标均达到和超过设计水平。