(57a) Infusion of Walnut Husk into Polyethylene

Black walnuts, juglans nigra, are indigenous to eastern North America, and the nut is composed of the kernel, shell, and husk. In commercial production, the nuts are harvested from the ground and sold to processors that de-husk the walnut and the de-husked walnuts are then shipped for further processing. The green, or fresh, husk is commonly discarded. Green walnut husks contain a wealth of polyphenolic compounds, tannins, and other chemicals, and the husk exhibits antimicrobial and antioxidant properties. Walnut husks may also be used as a bio-herbicide. These antimicrobial compounds may be extracted from black walnut husk using supercritical carbon dioxide with an ethanol modifier, with the resulting extract exhibiting antioxidant and antimicrobial properties. Additionally, supercritical carbon dioxide can cause polymers to swell, thereby allowing polymers to be infused with chemicals while exposed to supercritical carbon dioxide. It will be presented that carbon dioxide and ethanol can be used in extracting chemicals, as determined by HPLC-MS analysis, from walnut husk while simultaneously infusing chemicals into polyethylene. The resulting extract showed antioxidant potential as measured by the total phenolic content (TPC) assay and antimicrobial properties. The treated polyethylene exhibited antimicrobial effects compared to an untreated control. The treated polyethylene was also analyzed by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) and compared against a control. Additionally the treated polyethylene was then heated to its melt temperature and its antimicrobial properties re-evaluated.