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A mono-azetidine compound had been demonstrating a ring opening reaction with carboxylic acid (e.g., trimethylacetic acid, TMAA) and that resulted in an amino ester bond formation at ambient temperature. A triazetidine compound (trimethylolpropane tris(1-azetidinyl)propionate, TMPTA-AZT) was obtained via Michael addition of azetidine (AZT) to trimethylolpropane triacrylate (TMPTA). The carboxylic groups of anionic aqueous-based polyurethanes (PU) served as internal emulsifier, which stabilized PU dispersion and also served as PU curing sites. The triazetidine compound (TMPTA-AZT) was introduced into anionic aqueous-based PU dispersion as a new latent curing agent and that mixture became a single-component self-curable aqueous PU system. A crosslinked PU film was obtained from this PU system on drying at ambient temperature.The final polymer performance properties demonstrated the crosslinking behaviors of this new curing agent, TMPTA-AZT, with carboxylic ion-containing aqueous-based PU resins.

A new self‐polymerization took place between acrylic acid (AA) and a mono‐aziridine containing compound, e.g. methyl 3‐(aziridin‐1‐yl) propanoate (MAP) upon mixing that resulted in formation of a linear polyethyleneimine (PEI) with amino‐ester bonds. This self‐polymerization has a key reaction of ring opening reaction occurred between carboxylic acid and aziridine that led to an amino‐ester bond formation. The model reactions of trimethylacetic acid (TMAA) with MAP and then with ethyl acrylate (EA) were designed to demonstrat the self‐polymerization mechanism. The model reaction product at each stage related to that of polymerization was characterized by FT‐IR and FT‐NMR. The self‐polymerization occurred via three consecutive reactions at ambient temperature, which were acid‐base neutralization, aziridine ring‐opening and finally Michael addition reaction. Their average molecular weight of resulting PEI could be over 60,000 in aqueous medium or a higher polymer formation in bulk, which is insoluble in water or any organic solvent. This self‐polymerization process could have potential for adhesives, composite materials or other polymer applications.

Abstract A UV-cured polyurethane (PU)/nano-silica composite with a flame-retarded coating system was obtained from the composition of nano-silica containing a UV-curable PU oligomer and a UV-reactive phosphonic acid [ethylene glycol methacrylate phosphate (EGMP)]. The UV-curable PU oligomer was prepared by an addition reaction of 2-hydroxyethyl methacrylate (2-HEMA) with an NCO-terminated PU pre-polymer; this was then mixed with a methanol dispersion of nano-silica. The UV-reactive phosphonic acid (EGMP) was prepared by a reaction of 2-HEMA with phosphorus pentoxide (P2O5). The curing reaction of the PU/nano-silica composite coating system was carried out by UV irradiation with the aid of a photoinitiator (2-hydroxy-2-methylpropiophenone). The thermal properties of these PU/nano-silica composite coatings were investigated by the measurements of dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), respectively. A phosphorus (phosphonic acid) containing ingredient, EGMP in PU coating system that provides good adhesion to steel surface and flame retardation. Their physical properties (contact angle, hardness) and flame flammability [limiting oxygen index (LOI), UL-94 test] with various phosphorus contents (different dosages of EGMP) were also evaluated in this report.