Development of moisture cure polyurethane-urea coatings using 1,2,3-triazole core hyperbranched polyesters

This article reports the development of moisture cure polyurethane-urea coatings. The coating has been developed using different generations of novel 1,2,3-triazole core containing hyperbranched polyester polyols (THBP). For the synthesis of THBP, the core molecule, tetra hydroxyl-terminated di-triazole (THTD), has been synthesized by click reaction involving ethylene diazide and 2-butyne-1,4-diol. The polycondensation reaction between the core THTD and 2,2-bis (hydroxymethyl) propionic acid (Bis-MPA) at different mole ratios has been used to get first (THBPG-1), second (THBPG-2), and third (THBPG-3) generations of triazole core hyperbranched polyesters. The structural investigations of these THBPs have been carried out by H-1 NMR, C-13 NMR, and FTIR spectroscopy. The different generations of THBPs were further reacted with 1-isocyanato-4-[(4-isocyanatocyclohexyl) methyl] cyclohexane (H-12-MDI) at OH:NCO ratio of 1:1.2 to get -NCO terminated triazole core hyperbranched polyurethanes. They were cured under atmospheric moisture to get hyperbranched polyurethane-urea coatings and were named as THBPUG-1, THBPUG-2, and THBPUG-3. FTIR has been used to confirm the formation of polyurethane coatings. The TGA and DMTA have been used to determine the thermal stability and dynamic mechanical properties of the coatings, respectively. The corrosion resistance properties of the coatings have been studied by salt spray and electrochemical test. The coatings were also evaluated for microbial resistance. The results indicate that the thermal stability, glass transition temperature, and corrosion resistance properties increase with an increase in generation number of THBPs used for coating development. All three generations of coating films show excellent antimicrobial activity. Based on overall combined structure-property relationship study, these types of coatings will be useful as multifunctional applications in marine and moist environments.