Assessment of vinyl acetate polyurethane-based graft terpolymers for emulsion coatings: Synthesis and characterization

Abstract

Hybrid oligomers composed of polyurethane methacrylate (PUMA) and polyurethane acrylate (PUA) were synthesized by poly addition polymerization of polypropylene glycol (PPG 1000), 2,4- and 2,6-toluen diisocyanate (TDI 80/20) and 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate. Isopropanol was served as the isocyanate blocking agent. The grafting of either PUMA or PUA oligomers to the vinyl acetate monomer was implemented for the first time for improving the properties of the produced PU-co-VAc or (PUP_MA or PUP_A) terpolymers as new binders for emulsion coating formulations. The synthesized terpolymers were characterized with Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (¹H NMR), scanning electron microscope (SEM), gel permeation chromatography (GPC), minimum film forming temperature (MFFT), thermal gravimetric analysis (TGA), Zeta potential and mechanical properties. It has been shown that properties of the terpolymers and their corresponding films were greatly influenced by the grafting of PUMA and PUA at a low concentration level (5 wt%). Cured films of PU based vinyl acetate (PUP_MA or PUP_A) exhibited higher thermal stability and less weight loss compared to the vinyl acetate copolymer (PVAC). The synthesized PUP_MA and PUP_A terpolymers revealed enhanced efficiency as binders for emulsion paints in comparison to the PVAC copolymer.

GRAPHICAL ABSTRACT

The terpolymers composed of poly (vinyl acetate-co-butyl acrylate-co-PU) emulsions have excellent properties and high enhancements in emulsion paints as waterborne binders.

Keywords:

• Polyurethane acrylate
• polyurethane methacrylate
• vinyl acetate copolymers
• graft terpolymers
• emulsion paints