Organic–inorganic hybrid coatings prepared from glycidyl carbamate resins and amino-functional silanes

Organic–inorganic hybrid coatings were prepared from glycidyl carbamate (GC) functional oligomers and different amino-functional trimethoxysilanes via a systematic three-step reaction process. Initially, glycidyl carbamate functional oligomers isocyanurate glycidyl carbamate (IGC) and biuret glycidyl carbamate (BGC) were synthesized from the reaction of the polyisocyanurate of hexamethylene diisocyanate (HDT) with glycidol and the biuret adduct of hexamethylene diisocyanate (HDB) with glycidol, respectively. Then, the GC resins were mixed with 3-aminopropyl trimethoxysilane (APTMES), N-(2-aminoethyl) 3-aminopropyl trimethoxysilane (AEAPTMES) and p-aminocyclohexyl methane (PACM) at different stoichiometric ratios. In order to form the hybrid organic–inorganic networks, the materials were cured either at room temperature and humidity for more than 20 days or with an additional heat treatment at 80 °C for 1 h and then keeping the coatings at room temperature and humidity for more than 10 days. The observable change in the structure during network formation was monitored by FTIR spectroscopy. The cured coatings were characterized by thermogravimetric (TGA) and differential scanning calorimetry (DSC). Atomic force microscopy (AFM) was used to characterize the surface properties of the hybrid systems. AFM observation suggests the phase separation behavior. Coating properties such as König pendulum hardness, crosshatch adhesion, MEK double rub resistance and water contact angle of the coatings were also evaluated. Finally, structure–property relationships are given based on the variable parameters used.