Development of isocyanate-modified acrylic emulsion polymers for waterborne coatings

Abstract

This thesis focused on the development of acrylic polyurethane (APU) latex. The core-shell hydroxyl acrylic was synthesized via two-stage emulsion polymerization and it was further reacted with isophorone diisocyanate to produce APU latex. Non core-shell latex was prepared for comparisons. We had attempted to incorporate isobornyl methacrylate into the hydroxyl acrylic during the core or the shell emulsion polymerization.Fourier Transform Infrared Spectroscopy was used to identify the urethane/ urea linkage and to determine the isocyanate residue in the polymer film. The surface compositions of the APU latex were analyzed by X-ray Photoelectron Spectroscopy. The Tg measured by Differential Scanning Calorimetry and Minimum Film Formation Temperature of the APU latex were determined. The storage stability of the APU latex was monitored by the gradual shift in the particle size distribution during a pre-determined storage period at 50i??C.