Biodegradable packaging for corrosion inhibition via supercriticial fluid

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] The focus of this study is to develop a packaging material that is both biodegradable (BD) and provides corrosion protection for a packaged metal substrate. In this study, supercritical carbon dioxide is used to infuse Ecoflex[registered trademark] resin, a BD aliphatic-aromatic copolyester, with sodium nitrite (NaNO[subscript 2]), which is a common volatile corrosion inhibitor (VCI). The effects of supercritical fluid (SCF) density upon the infusion depth were examined first. For this study, 10 g of Ecoflex[registered trademark] was infused with NaNO[subscript 2] using SCF densities that ranged from 0.15-0.62 g/cm[subscript 3]. The results demonstrated that fluid density does not play a significant role in infusion depth. However, the influence of temperature on infusion depth is significant at 95%. The second phase of this work focused on producing a VCI-infused package and determining its ability to prevent iron corrosion. The corrosion protection capabilites of VCI-infused biodegradable polymer was compared to packages of VCI-infused linear low-density polyethylene (LLDPE), uninfused Ecoflex[registered trademark], uninfused LLDPE, and an unpackaged control. The corrosion rate of the control, uninfused LLDPE, VCI-LLDPE, uninfused Ecoflex[registered trademark], and VCI-Ecoflex[registered trademark] were 0.00353 mm/yr, 0.00089 mm/yr, 0.00048 mm/yr, 0.00297 mm/yr, and 0.00033mm/yr, respectively. The VCI-infused packages provided the most protection, with the VCIEcoflex[registered trademark] resulting in 90.7% less corrosion. Furthermore, scanning electron microscopy (SEM) studies show that the film integrity was maintained during the SCF infusion process. These findings demonstrate the infusion capability of a SCCO[subscript 2] system, and help elucidate the effects of processing conditions on the infusion quality of the final product. Additionally, the corrosion protection ability of the infused films was verified.--From public.pdf