Study of DGEBA and Novolac Adhesive Solutions between Ceramic and Steel Substrates

Abstract

The industrial application (under a confidential clause) concerns a ceramic/steel assembly. This PhD research is concerned with providing a reliable industrial bonding between ceramic and steel using structural adhesive. This industrial joint shall withstand a wide range of temperatures with brutal thermal changes. This paper focuses on the adhesive formulation. Indeed, we needed to compromise the adhesive flexibility: soft enough to resist the thermal stresses and compensate the coefficient of thermal expansion mismatch between the two substrates. We find this good compromise with DGEBA and Novolac epoxy based adhesive separated or blended. The influence of the different formulation parameters on the initial properties was studied by chemical, rheological and thermal tests on adhesive samples. Depending on those formulations, we observed different behaviours in term of glass transition temperature, cross-linking time and flexibility.

Study of DGEBA and Novolac Adhesives Hydrothermal Ageing for a Ceramic/ Steel Substrates Bonding Assembly

“…So the water has partly reacted with the matrix by hydrogen bonds as evidenced by rheological approach and/or chemically reacted by hydrolysis with the thermoset matrix [5][6]. In a previous article [36], for an unaged sample, the carbonyl band (C=O) which appears between 1710 and 1780cm -1 has been attributed to the Gilbert mechanism [37] describing the oxazolidinone (containing a carboxylic acid group) formation by a chemical reaction between secondary amine groups and oxyran groups. The bands between 1680 and 1710cm -1 have been attributed to amide groups' formation.…”