Dynamic Curing Agents for Amine-Hardened Epoxy Vitrimers with Short (Re)processing Times,Macromolecules

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Dynamic Curing Agents for Amine-Hardened Epoxy Vitrimers with Short (Re)processing Times
Macromolecules ( IF 5.1 ) Pub Date : 2020-03-24 , DOI: 10.1021/acs.macromol.9b02526
Yann Spiesschaert ₁ , Marc Guerre _{1,

2} , Ives De Baere ₃ , Wim Van Paepegem ₃ , Johan M. Winne ₁ , Filip E. Du Prez ₁

Affiliation

This work presents a straightforward strategy to introduce highly dynamic and adaptable cross-links into common epoxy resin formulations. For this, an oligomeric amine-based curing agent containing vinylogous urethane (VU) bonds was developed. This novel polyfunctional amine curing agent can be used as a drop-in solution for existing epoxy resin technologies, resulting in transparent, rigid, and, at the same time, highly reprocessable catalyst-free epoxy vitrimers. The oligomeric VU-curing agents are prepolymerized via a straightforward condensation reaction between acetoacetates extended with different classical amine monomers and epoxy hardeners. It is found that vitrimer properties can be readily introduced into these epoxy formulations by converting <50 mol % of the hardener’s amine functionalities into dynamic vinylogous urethane bonds. In this way, epoxy vitrimers can be obtained with material properties comparable to ones of the VU-free epoxy formulations. In addition, remarkably short processing times are observed in the absence of any catalyst, and the material displayed very short stress relaxation times and good recyclability, actually representing the most performant VU-based vitrimers so far. Furthermore, a proof of concept for its use in obtaining glass-fiber-reinforced epoxy composites is also presented.

中文翻译：

用于胺强化环氧微粉的动态固化剂，处理时间短（再处理）

这项工作提出了一种简单的策略，可以将高动态和适应性交联引入普通的环氧树脂配方中。为此，开发了包含乙烯基氨基甲酸酯（VU）键的低聚胺基固化剂。这种新型的多官能胺固化剂可用作现有环氧树脂技术的滴入溶液，可产生透明，刚性且同时可高度再加工的不含催化剂的环氧微晶玻璃。低聚VU固化剂通过在用不同的传统胺单体扩展的乙酰乙酸酯与环氧固化剂之间的直接缩合反应进行预聚合。已发现，通过将硬化剂的胺官能度的<50 mol％转换为动态的乙烯基类氨基甲酸酯键，可以轻松地在这些环氧配方中引入三聚体性能。以此方式，可以获得具有与无VU的环氧制剂的材料性能相当的材料性能的环氧微晶玻璃。另外，在没有任何催化剂的情况下，观察到非常短的加工时间，并且该材料显示出非常短的应力松弛时间和良好的可回收性，实际上代表了迄今为止性能最强的基于VU的氧化钛。此外，还提出了其用于获得玻璃纤维增强的环氧复合材料的概念证明。

更新日期：2020-04-24

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