Insights into volatile presence within epoxy amine coatings using nano-thermal analysis

Thermoset polymers are widely used as the matrix in protective organic coatings, where solvents are commonly added to adjust viscosity and control drying times. Whilst the majority of solvent evaporates rapidly during the curing process, it is well-known that some degree of residual solvent is often retained in the matrix. Here we examine the effect of solvent retention on local thermal properties in both well-defined model coatings assembled using reagent grade materials and simplified industrial epoxy-phenalkamine formulations. Whilst for ambient cured systems conventional DSC analysis is unable to detect the presence of solvent, uniquely, nano-thermal analysis (NanoTA) is used to provide evidence of exacerbated solvent retention at the polymer-metal interface in model epoxy-amine systems, whereas in the industrial coating, multiple transition temperatures are detected, corresponding to solvent mixtures within the network.