Selective surface modification of TiO2-coated polypropylene by photodegradation

It is known that TiO2 coating of polymers protects against UVC light, despite degrading when under UVB or UVA light. We studied carefully polypropylene coated with TiO2 under UVC light, and we found the formation of hydroxyls and no formation of carbonyls, being this technique eligible for selective modification of polypropylene surfaces with hydroxyls. Besides that, we also found the formation of insaturation between carbons produced by the Norrish reaction in pristine polypropylene, thanks to a simple experimental technique proposed in this paper based on FTIR spectral subtraction. The samples were thermal-pressed to simulate a thermoforming processing and verify whether there was any influence on the photostabilization provided by TiO2 coating.