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The Effect of Metal Substrate (Al, Cu, Ag, and Au) on the Photodegradation of Polymers: Polyacrylonitrile

Al-backed PVF film shows more photodegradation than does the non-metalized PVF film. The effect of several metal substrates (Al, Cu, Ag, and Au) on the photodegradation of polyacrylonitrile (PAN) has been examined. Under oxidative conditions, the order of PAN photodegradation in M/PAN films is shown to be Cu/PAN » PAN » Al/PAN > Au/PAN > Ag/PAN. Formation of carbonyl group during the photodegradation is predominant in the cases of Al and Au. Under nonoxidative conditions there is no evidence of carbonyl group formation, but the photodegradation of Cu/PAN is still substantial. Under oxidative conditions the Cu/PAN film begins to char after approximately one hour, compared with four and a half hours under nonoxidative conditions. The photodegradation mechanism in the range of 250 ≤ λ ≤ 400 nm suggests the formation of M(CN) x species, but no such species are detected spectroscopically at the energy employed. A catalytic effect of metal films on the photodegradation of PAN is obvious.