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Further insight on amine-metal reaction in epoxy systems
Surfaces and Interfaces ( IF 5.7 ) Pub Date : 2021-01-23 , DOI: 10.1016/j.surfin.2021.100959
Christophe Drouet , Fabrice Salles , Zineb Fritah , Olivier Marsan , Carole Thouron , Maëlenn Aufray

Among thermosetting polymers, epoxy resins are major components of adhesives, sealants, paints and composites. Polymerization is often achieved by reaction of epoxy monomers like DGEBA with amine hardeners such as DETA. Previous works showed that polyamines interact with metal (hydr/oxide) substrates leading to the formation of an interphase involving the chelation of surface metal ions. In this work, we further explored the interaction between DETA and aluminum (hydr)oxide, denoted Al, via a combined experimental and modeling approach. We inspected in depth by DSC the modifications of glass transition temperature Tg and change in heat capacity ΔCp after curing, allowing us quantifying the impact of Al amount on DGEBA/DETA degree of cure α. A new parameter, the “percentage of inhibition of cure” denoted α¯, was defined reaching up to ~4 % in our experimental conditions. In parallel, in situ mixing calorimetry confirmed the exothermic character of DETA interaction with Al with various degrees of division. DFT calculations were carried out to examine DETA/Al3+ chelates. Among plausible chelate configurations, one was associated with a lower conformational energy and shorted Al-N bond lengths, suggesting greater stability. Calculated and experimental Raman spectra were additionally investigated, allowing us to discuss further about the DETA/Al3+ chelates at play.



中文翻译:

对环氧体系中胺金属反应的进一步了解

在热固性聚合物中,环氧树脂是粘合剂,密封胶,油漆和复合材料的主要成分。通常通过使环氧单体(如DGEBA)与胺类硬化剂(如DETA)反应来实现聚合。先前的研究表明,多胺与金属(氢/氧化物)基质发生相互作用,导致形成涉及表面金属离子螯合的中间相。在这项工作中,我们通过组合的实验和建模方法,进一步探讨了DETA与(铝)氧化物铝(氢氧化铝)之间的相互作用。我们深入检查通过DSC玻璃化转变温度T的修改和改变热容量ΔC p固化后,我们可以量化Al量对DGEBA / DETA固化度α的影响。表示一个新参数,即“抑制治愈的百分比”α¯定义为在我们的实验条件下达到〜4%。同时,原位混合量热法证实了DETA与Al相互作用的放热特征,且具有不同的分度。进行DFT计算以检查DETA / Al 3+螯合物。在可能的螯合物构型中,一种与较低的构象能和较短的Al-N键长有关,表明具有较高的稳定性。还对计算的和实验的拉曼光谱进行了研究,使我们可以进一步讨论DETA / Al 3+螯合物的作用。

更新日期:2021-02-07
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