Preparation and properties of reactive aqueous polyurethane dispersion modified by polysiloxane

Aqueous dispersions of reactive polyurethane modified by polysiloxanes were prepared from N-[(1,1-dimethyl-2-acetyl) ethyl]-β-dihydroxyethylamino propanamide (DDP) and α, ω-bis (3-hydroxypropyl)-terminated polysiloxane (PDS). Viscosity, surface tension, particle size, particle size distribution, particle morphology and storage stability of aqueous dispersions were investigated. The water resistance, solvent resistance, gel content, tensile strength, elongation at break, morphology of fractural section and thermal stability of prepared latex films of aqueous dispersions were also studied. The viscosity and surface tension raise with increase of DDP content in aqueous dispersions and reduce with increase of PDS content. Thermal stability of the films increases with incorporation of either DDP or PDS. Water resistance, solvent resistance and gel content of films are distinctly enhanced by crosslinking reaction during film formation. Compared with aqueous dispersion of sole polyurethane, water absorption of the latex film decreases by 45.83%, toluene adsorption decreases by 15.53% and gel content increases by 9.62% for the samples with the best performance.