Investigation of reaction mechanism of epoxy resins with amide functional groups

Abstract

Epoxy resins are used for many applications due to their noteworthy properties such as low creep, reasonable elevated temperature performance, chemical resistance and good adhesion to various substrate, etc. Epoxy resins gain such characteristics even at moderate level of crosslinking often referred as curings. There are various types of hardeners that initiate curing reaction, which all bring some characteristics to the material depending on their chemical and physical features. The information we have up to now, amides as hardener are not used as much as other kinds of curing agents like amines, anhydrides and acids, etc. Interestingly there are only a few reports on the reaction of epoxides with amides in general. Furthermore, in these limited studies done with amide and epoxy resins, there is little information about the effect of amide or the epoxide structure on these reactions, since the cured product analyses were mostly limited to FTIR analyses due to the solubility issues. Here, synthesis of soluble samples and their further spectroscopic analyses were aimed. Thus depending on these results about the structure of product, the idea about probable reaction pathway was developed. Also, temperature and heating time were adjusted to carry out the reaction under suitable conditions. Monomeric amide sources were used to avoid from complete crosslinked structure and provide solubility. Aromatic group containing amide and epoxy were used as well for comparison of effect of aromaticity and aliphaticity on reaction. In addition to FTIR and DSC, 1H-NMR and LS-MS analysis were realized for soluble samples.