Surface modification of recycled polymers in comparison to virgin polymers using Ar/O2 plasma etching

Low-pressure plasma etching of a recycled polyethylene terephthalate (PET) film is studied in comparison to virgin PET and polypropylene (PP) using a capacitively coupled radio frequency (RF) plasma reactor. Recycled polymers are distinguished by increased impurity content and weakened mechanical properties, both affecting plasma etching and adhesion processes. Mild plasma conditions have been selected to maintain the material bulk properties of the polymers. The etch rates and the morphology of the polymer samples were thus determined at floating potential compared with etching at the RF electrode for varying argon/oxygen gas mixtures, etching duration, and sample size. Thermoanalytical and X-ray techniques were used to characterize the polymer before and after the plasma etching treatment. Finally, adhesive-tape peel tests proved that excellent adhesion of silver coatings can also be achieved on a plasma-treated recycled PET film.