Surface modification of polypropylene substrates by UV photografting of methyl methacrylate (MMA) for improved surface wettability

Despite polypropylene is one of the most used commodity plastics, its adhesion properties are remarkably restricted by its non-polar nature which leads to low wetting properties and, consequently, poor adhesion behavior. We report the use of ultraviolet photografting process of methyl methacrylate (MMA) monomer as an efficient chemical treatment for surface activation of polypropylene. Contact angle measurements are used for evaluating changes in polypropylene wetting properties together with surface free energy calculations. Chemical changes are showed in terms of the exposure time to UV radiation. Scanning electron microscopy has been used to evaluate topography changes in a qualitative way; atomic force microscopy has been used for a quantitative evaluation of surface changes in terms of roughness. The use of Fourier transformed infrared spectroscopy has revealed the nature of the chemical changes induced by the photografting process of MMA.