Effect of catalyst type on the structure, mechanism and thermal properties of melamine-formaldehyde resins

Abstract

The uncertainty of the structure of melamine-formaldehye polymer is one of the important factors limiting its widespread application. The chemical reactions of melamine are almost always reversible, so controlling the microstructure is difficult. For the synthesis of polymer particles in water, it is unclear how the type of catalyst affects the microstructure of melamine-formaldehye polymers. Therefore, we conducted a detailed study to understand how different catalyst types( including 10% NaOH, trimethylamine,and a Na₂CO₃-NaHCO₃ buffersolution)affect the hydroxymethylation reaction, structure and the thermal properties of the melamine-formaldehye polymer). The results showed that with the same molar ratio and pH conditions, the use of triethylamine as catalyst in the melamine-formaldehye polymer increased the possibility of side reactions in the hydroxymethylation reaction. However, the occurrence of side reactions has a favorable effect on the thermal properties of melamine-formaldehyepolymers. Specifically, melamine formaldehyde polymers synthesized using triethylamine as a catalyst exhibit higher thermal decomposition characteristic temperatures, lower kinetic values, and higher reactivity. These results provide insights into the effect of catalyst type on the reaction mechanism, microstructure and thermal properties of melamine-formaldehye polymers, which may prove useful for their improved and controlled synthesis.