Preparation and characterization of waterborne polyurethane/polyacrylate emulsions containing sulfonate groups

Polyurethane/polyacrylate emulsions (SDPUA) with high solid content were obtained by using carboxyl groups and sulfonate groups as hydrophilic chain-extenders and internal emulsifiers through surfactant-free emulsion polymerization. Polyurethane/polyacrylate emulsions with ethylene diamine (EDA) as chain-extender (EDPUA) were also prepared. The influence of the different 2,4-diamino-benzenesulfonic acid sodium salt (DABS) content on the properties of the SDPUA products was investigated. The main properties of EDPUA were also discussed compared with the SDPUA samples. Dynamic light scattering results showed that when DABS/DMPA molar ratios increased from 1/4.7 to 1/2.28, the particle size increased from 72.2 to 99.7 nm. The particle size of EDPUA emulsion was larger. The steady rheological measurements illustrated that the viscosity decreased with the shear rate increase and the emulsions were displayed as pseudoplastic behavior. Attenuated total reflection Fourier transform infrared results demonstrated the SDPUA products were successfully prepared. As the function of DABS groups, the thermal stability was enhanced. With the increment in DABS/DMPA molar ratio, the contact angles on SDPUA membranes decreased, and the surface free energies increased. The T-peel strength increased to 88.2 N/mm and DABS/DMPA molar ratio increased to 1/2.28, and it was larger than the EDPUA samples. The compatibility of the dual phases was enhanced.