Synthesis and properties of aqueous cyclic carbonate dispersion and non-isocyanate polyurethanes under atmospheric pressure

Abstract

Cyclic carbonates (TMC/PMDC/BTDC) were synthesized at atmospheric pressure by glycerine carbonate (GC) reacting with trimellitic anhydride (TMA) / pyromellitic anhydride (PMDA) / benzophenone-3,3′,4,4′-tetracarboxylicdianhydride (BTDA). 1H NMR spectra showed that the cyclic carbonates have 2.62, 3.72 and 3.43 cyclic carbonate functionality, respectively. TMC/PMDC/BTDC were further neutralized by dimethylethanolamine and dispersed in water to prepare TMC/PMDC/BTDC aqueous cyclic carbonate dispersion. They exhibited no stratification after 5000 r/min centrifugation for 60 min, indicating their good stability. The particle sizes of these dispersions ranged from 30 to 120 nm with the Zeta potential from -55 to -79.5 mV. A series of waterborne non-isocyanate polyurethane (T-WNIPU, P-WNIPU and B-WNIPU) coatings were successfully prepared by reacting TMC/PMDC/BTDC cyclic carbonate aqueous dispersion with diamines. The WNIPU coatings all displayed excellent chemical resistance to toluene, xylene, alcohol and 5% H2SO4 as well as high gloss, impact resistance, adhesion, flexibility and hardness. The Tg of WNIPUs was in the range of 31.4 °C–100.2 °C. All the WNIPUs coatings have good thermal stability with 5% weight loss temperatures (T5%) above 242 °C.