Plasma-induced graft co-polymerization of acrylic acid onto the polyurethane surface

We introduced carboxylic groups on the surface of polyurethane (PU) with the aid of oxygen plasma treatment and the post-grafting of acrylic acid (AAc) in an aqueous solution. After plasma treatment, PU was exposed to the air to generate peroxides. Peroxides were confirmed by the 1,1-diphenyl-2-picrylhydrazyl method. We chose different parameters of plasma treatment to get the optimum condition for introducing maximum peroxides on the surface. Peroxides are known to be the species responsible for initiating the graft co-polymerization when PU reacts with AAc to produce AAc grafted PU. The AAc grafted on the surfaces was characterized by water contact angle measurement, Fourier transform infrared by attenuated total reflectance and electron spectroscopy for chemical analysis and optical microscopy. After confirming a successful grafting of AAc, we studied the effect of reaction temperature, reaction time, monomer concentration and Mohrʹs salt on the grafting degree of AAc.