The influence of structural modification and composition of glycidyl carbamate resins on their viscosity and coating performance

The synthesis, characterization, and coatings performance of a series of glycidyl carbamate (GC) resins synthesized from a hexamethylene diisocyanate biuret resin, glycidol, and alcohols were explored. The partial replacement of glycidol with alcohols was explored as a way to reduce the viscosity of multifunctional GC resins. Six modified GC resins were obtained by replacing one-third of the glycidol with alcohols and ether alcohols. The modified GC resins were characterized using FTIR and ¹³C NMR. The alcohol-modified GC resins had significantly lower viscosity than that of the control GC resin. The effect of amount of alcohol modifier on resin viscosity was also studied by making a series of resins with different levels of modifier. Both amine-cured and self-crosslinked coatings were prepared from the resins. Coating properties such as hardness, impact strength, methyl ethyl ketone double rubs, flexibility, and adhesion were studied. Differential scanning calorimetry and thermogravimetric analysis were also used to study the thermal properties of the coatings. The resin structures and their coating performance showed an excellent correlation. The coating performance was found to be governed by the type of modifier, structural compositions of the modifier in the resins, type of amine crosslinkers, and techniques of crosslinking used.