Catalytic curing agents

Summary Adducts of trichloro and triisothiocyanato borane with alkyldimethylamines are effective latent catalysts for epoxy homopolymerization. The lower stability triisothiocyanato borane adducts initiated the polymerization at lower temperatures than the chloro derivatives. In both cases the borane moiety was converted into [B(OR)₄]^- by reaction with the oxirane ring initiating the reaction by the formation of cations. Free amine was detected in the curing resin but was not directly involved in the polymerization mechanism. The formation of oxazolidone rings was observed when triisothiocyanato borane adducts were used. The behaviour of some of the decomposition products of the adducts was also examined.     

Curing octaepoxysilsesquioxane with different curing agents

Octaepoxysilsesquioxane (POSS-Ep) was first synthesized by the hydrolysis and condensation of γ-[(2,3)-epoxypropoxy]propyltrimethoxysilicane (KH-560) with the presence of ethanol and HCl at 55°C for 72 h. Then, it was cured with 4,4′-diaminodiphenylsulfone (DDS) and methylnadic anhydride (MNA), respectively. The curing reactions between POSS-Ep and DDS or MNA were investigated by FTIR. Thermal stability of the cured nanocomposites was studied by TGA. The micromophologies of the obtained hybrids were observed by SEM. FTIR results show that POSS-Ep can be cured completely with DDS or MNA to obtain the final organic–inorganic (O–I) hybrids after the same experimental curing cycle: 120°C/2 h + 140°C/2 h + 160°C/2 h + 180°C/2 h + 200°C/2 h. TGA results show that POSS-Ep/DDS hybrid displays better thermal stability than that of POSS-Ep/MNA hybrid. Initial thermal degradation temperature (Tdi) of POSS-Ep/DDS hybrid is 420°C, 195°C higher than that of POSS-Ep/MNA (225°C). SEM images of the fracture surfaces of the hybrids suggest the cured POSS-Ep possesses good mechanical properties. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

聚酰胺和腰果酚类固化剂对环氧树脂固化性能的影响

以环氧树脂(EP)为基体,低Mr(相对分子质量)聚酰胺(650)、腰果酚为固化剂,加入适量的水泥、石膏粉或滑石粉等填料,制备了EP胶粘剂。研究结果表明:650/EP体系的固化速率大于腰果酚/EP体系,前者的硬度高于后者;650和腰果酚混合使用会较大程度提高EP固化物的韧性,但固化剂类型对EP固化物压缩强度和拉伸剪切强度的影响并不显著;当m(650)∶m(腰果酚)=20∶30时,EP固化物的综合性能相对最好;增塑剂的加入能缩短固化时间、提高EP固化物的力学性能,而填料的加入可提高EP固化物的硬度、降低成本。     

一种建筑结构胶用环氧固化剂的研制

选用了甲基环戊二胺为主要原料进行曼尼希改性,探讨了甲基环戊二胺曼尼希改性中原料物质的量比、温度、含水率等因素对产品性能的影响。对改性环氧固化剂进行了分析测试和配制的建筑结构胶的力学性能测试。测试结果表明,甲基环戊二胺曼尼希改性的产品是一种理想的结构胶用环氧固化剂。     

单组分环氧树脂胶粘剂用潜伏性固化剂

对单组分环氧树脂胶粘剂用潜伏性固化荆的研发进展进行了扼要的综述.     

脲醛树脂固化剂体系的研究

固化剂体系对脲醛树脂的固化有显著影响,根据固化剂的作用机理,对单组分、双组分和复合固化剂体系进行了系统研究,旨在找出不同固化剂体系在不同条件下的变化趋势。     

水性环氧固化剂及其改性技术

概述了水性环氧固化剂的分类,介绍了离子型和非离子型水性环氧固化剂的发展概况及制备方法,综述了近年来水性环氧固化剂的研究开发进展,其中包括有机硅改性水性固化剂,含磷阻燃水性固化剂,聚氨酯改性,无机纳米粒子及有机氟改性水性固化剂。     

环氧树脂固化剂研究进展

介绍了近年来环氧树脂固化剂研究的一些最新趋势。     

复合固化剂对低甲醛脲醛树脂固化特性的影响

为解决低甲醛UF(脲醛树脂)固化速率较慢、胶接强度较低等问题,采用草酸、磷酸和过硫酸铵(APS)与尿素、氯化铵组成复合固化剂,并着重探讨了复合固化剂对低甲醛UF胶粘剂(甲醛含量0.01%)在竹刨花板中的固化性能和胶接强度的影响。研究结果表明:APS部分代替氯化铵可降低UF体系的p H和固化温度,并且所得复合固化剂可改善UF胶粘剂在竹刨花板中的固化性能和胶接强度;少量的草酸和磷酸虽可快速降低UF体系的p H,但p H过低时会导致UF胶粘剂的适用期缩短、胶接强度明显降低。     

Improving the curing process and thermal stability of phthalonitrile resin via novel mixed curing agents

High curing temperature (including post‐curing temperature) and long curing time of phthalonitrile resins make them thermally stable but difficult to process. In this paper, novel mixed curing agents (CuCl/4,4′‐diaminodiphenylsulfone (DDS) and ZnCl₂/DDS) were firstly designed for solving these problems. Bisphenol‐based phthalonitrile monomer (BP‐Ph; melting point: 228–235 °C) was synthesized and used as the curing precursor. Differential scanning calorimetry results indicated that BP‐Ph cured with CuCl/DDS and ZnCl₂/DDS exhibited curing temperatures close to the melting point of BP‐Ph with curing ending temperatures of 225.4 and 287.1 °C, respectively. Rheologic investigations demonstrated obvious curing reactions of BP‐Ph occurred with the mixed curing agents at 220 °C. Thermogravimetric analysis showed that BP‐Ph cured by CuCl/DDS or ZnCl₂/DDS maintained 95% mass at 573 or 546 °C, respectively, at a post‐curing temperature of 350 °C for 2 h. Reasonable long‐term thermo‐oxidative stability was also demonstrated. When the post‐curing temperature decreased to 290 °C, char yield at 800 °C of BP‐Ph cured by CuCl/DDS was 77.0%, suggesting the curing procedure can be milder when using mixed curing agents. © 2017 Society of Chemical Industry     

Effect of aromatic and aliphatic amines as curing agents in sulfone epoxy monomer curing process

The kinetics of the curing of sulfone epoxy (SEP) monomers using aromatic and aliphatic amine curing agents was studied via differential scanning calorimetry (DSC). SEP curing is a two-stage process involving SEP/electron donation and electron donation to either aliphatic or aromatic curing agents. The SEP/electron donation curing process occurred readily since semi-electron-withdrawing curing agents are induced by nucleophilic substitution in the first stage. In the second stage, SEP is cured by the semi-electron-withdrawing curing agents. The kinetic parameters of the curing process were determined using a conversional method derived from Ozawa’s and Kissinger’s methods, which are typically used for kinetic analysis of data for thermal treatments. The higher melting points and steric bulk of the aromatic curing agents resulted in higher curing activation energies than for the aliphatic curing agents. The aliphatic curing agents also increased the activation energy of the curing process due to their electron-withdrawing and cross-linking properties as well as the viscosity of the epoxy/amine curing system. Cured SEP/aromatic curing agent materials possessed higher glass transition temperatures than cured SEP/aliphatic curing agent materials.     

生物质环氧树脂固化剂的研究进展

综述了近年来生物质环氧树脂固化剂(BEPCA)的研究进展,主要包括以腰果酚、香兰素、松香、木质素和植物油等作为原料制备的生物质胺类固化剂、生物质酸酐类固化剂和多元酚、羧酸及酯类生物质固化剂等;详细介绍了上述BEPCA的结构、制备方法、合成路线以及其固化产物的性能;最后,总结并展望了BEPCA未来的发展趋势.     

Crown ethers as new curing agents for epoxy resins

Different crown ethers (4‐aminobenzo‐15‐crown‐5 (4‐aminobenzo‐15‐C5), 1,4,10,13‐tetraoxa‐7,16‐diazacyclooctadecane (diaza‐18‐crown‐6), tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (H₄DOTA) and tetraazacyclododecane‐1,4,7,10‐tetraacetamide (H₂ODDA)) were used as curing agent for bisphenol A diglycidyl ether (BADGE, n = 0). The maximum enthalpy change for all systems except that formed by the epoxy resin with H₄DOTA corresponds to a stoichiometric ratio, since from this value the reaction enthalpies decrease when the proportion of epoxy increases. Heteropolymerization reaction occurs in all the crown ethers. Etherification reactions occur at temperatures much lower (30 °C less) than for the porphyrin systems studied in which a second signal appears at 300 °C. The etherification is evidenced by a slight shoulder in the thermograms for H₄DOTA and H₂ODDA. The systems BADGE (n = 0)/4‐aminobenzo‐15‐C5 and BADGE (n = 0)/diaza‐18‐crown‐6 improve the thermal stability of the epoxy resin by 30 °C approximately while the improvement for BADGE (n = 0)/H₄DOTA and BADGE (n = 0)/H₂ODDA is about 60 °C. © 2017 Society of Chemical Industry     

新型烯丙基芳香二胺的合成及其固化特性研究

以溴丙烯和芳香族二酚为原料,通过缩合、重排2步反应制备了一系列烯丙基二酚化合物。以所合成的烯丙基二酚为原料,进一步与4-溴硝基苯,通过Williamson反应和还原反应制备了一系列新型烯丙基取代二胺单体。以2,2-双[4′-(4″-氨基苯氧基)-3′-烯丙基苯基]丙烷(APAP)为例,研究了其对环氧树脂以及双马来酰亚胺树脂的固化行为。结果表明,这类二胺固化剂对于上述树脂体系均具有良好的固化效果,固化物具有良好的耐热性能以及耐溶剂稳定性。     

Structural-mechanical properties of organosilicate composites with introduced curing agents

A systematic investigation on the rheological properties of five organosilicate suspensions of the “polyorganosiloxane-muscovite-talc-rutile-aminopropyltriethoxysilane-toluene” composition is undertaken. It is established that the sedimentation processes affect the energy characteristics of the surface of the organosilicate coatings prepared by curing the initial suspensions. The chemical processes occurring during long-term storage of the composites with introduced curing agents have an effect on the redistribution of the contributions from the polar and dispersion components to the total surface energy of the coating.     

几种胺类固化剂对环氧树脂固化行为及固化物性能的影响

固化剂结构对环氧树脂的固化行为和固化物性能具有重要影响,本文研究了聚醚胺(D-230)、异佛尔酮二胺(IPDA)和3,3'-二甲基-4,4'-二氨基-二环己基甲烷(DMDC) 3种胺类固化剂与实验室自制的低翻度环氧树脂A进行固化反应.通过薪度分析、红外(FTIR)光谱分析、DSC分析等手段研究了环氧树脂与固化剂反应程度...     

曼尼希碱环氧树脂固化剂的研究进展

阐述了曼尼希碱型环氧树脂固化剂的合成原理、合成方法和发展历史与发展趋势,并就增加固化剂韧性、耐热性、降低固化剂黏度和开发水下固化剂以及改进固化剂生产工艺等方面进行了探讨。