YELLOW STAIN ON TINPLATE: AN APPROACH BY FTIR SPECTROSCOPY.

Tinplate cans affected by tonality changes on their unvarnished bodies as well varnished lids were compared with other ones without defect; characterizing by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR). The Infrared analysis let identify on defected bodies the absorption bands for Sn-O-Sn bond at 609 and 619 cm-1; while the polymer on top cans with tonality changes showed an absorption reduction at 3000 cm-1 related to OH bonding band; as well the picks related to varnish oxide groups at range of 1700 to 600 cm-1 decreased. The results link the defect with the oxidation of protecting metal and polymer dehydration. [ABSTRACT FROM AUTHOR]