This thesis reports on our preliminary development of methods used to assess the risks that polymer/clay nanocomposite (PCN) food packaging... Show moreThis thesis reports on our preliminary development of methods used to assess the risks that polymer/clay nanocomposite (PCN) food packaging pose to consumers. PCN with 1% - 7% (w/w) montmorillonite (MMT) clay and 3 mass equivalents of maleic anhydride-grafted polyethylene (MAPE) as a compatibilizer dispersed in low-density polyethylene (LDPE) was successfully extruded into thin, free-standing films using a pilot-scaled microcompounder with 65 mm film device. These films had good optical clarity and a reasonably consistent thickness of 35 ± 3 μm. An oxygen permeability analyzer was used to measure oxygen transmission rate and permeability of these fabricated films to demonstrate that they perform similarly to PCN barrier materials intended for commercial applications; these results showed that the films with the highest amount of added clay had better barrier properties than the neat LDPE films. In preparation of experiments to assess whether clay particles can be released from these materials during intended conditions of use, we also explored effective digestion and trace-metal analysis (Inductively Coupled Plasma-Optical Emission Spectroscopy) methods of both pure clay and MMT/MAPE/LDPE films. This work resulted in an effective digestion protocol to fully digest neat clays and PCN films, as well as an analysis method that provides for a 5-orders-of-magnitude linear detection range and single-digit parts-per-billion detection limits for aluminum and magnesium. Silicon was a more challenging element and efforts to eliminate environmental contamination of samples with this element were unsuccessful. While the work presented in this thesis is largely preliminary and numerous questions remain unanswered, the PCN fabrication and ix characterization methods developed here will be invaluable in our future efforts to understand the risks that nanocomposite food packaging materials pose to human health. M.S. in Food Process Engineering, July 2014 Show less
