Abstract:

Acrylic/polyurethane(PUA) hybrid emulsion has been prepared by water-borne polyurethane(WPU) modified with acrylic resin. A method for adding different mass fraction of acrylic(AC) into polyurethane(PU) polymers is proposed and verified through designed experiments. With increasing the polyacrylate(PA) mass fraction in the copolymer, the appearance of the emulsion changes from transparent to opacity, in the meantime, the particle size is increased. The TEM result reveals that PUA latex particles present clear core-shell structure and regular shape, and the size distribution is within the range of 60～120 nm. The results of FTIR indicate that the hydrogen bonding effect of PU hard segment first increased and then decreased, while the ordering of hard segment decreased with increasing the AC mass fraction. Compatibility and degree of mixing were developed under 75%AC added in copolymers. With increasing PA mass fraction, one glass transition temperature existed in the copolymers before the content of AC arrived 75%. Thermogravimetric analysis(TGA) shows that the temperatures for the maximal thermal mass-loss rate rose from 363 ℃ to 412 ℃, and water absorption for samples decreased from 11.3% to 5.7% with the increase of AC fraction. Additionally, the elasticity modulus of PUA was raised from 16.4 to 47.6 MPa, while the tensile strength was increased from 9.0 to 23.7 MPa, and the elongation at break changed from 365% to 408%. Furthermore, the composite latex viscosity is decresed, and the drying time is shortened, while glue film adhesion force becomes better.

Key words: WPU, unsaturated macromolecules monomer, hybrid emulsion, graft copolymerization