Titanium dioxide is photocatalytic and the possibility of the
photocatalytic effect of the film in causing degradation of the
BOPP polymer must be considered. This was tested by using a
10 nm Al2O3 buffer layer between the polymer and the TiO2 layer
and repeating the UV absorption and mechanical strength tests
of the study for the new samples. According to the results, no
clear reduction in the degradation of the polymer was detected.
Thus, it can be concluded that the TiO2 layer itself did not have
a harmful effect on the BOPP matrix during the original UV
exposures.