Degree Type

Creative Component

Semester of Graduation

Fall 2018


Food Science and Human Nutrition

First Major Professor

Keith Vorst


Master of Science (MS)


Food Science and Technology


With increased regulation of recycled materials, such as minimum content claims for bags and rigid containers in California, additional research was needed to understand how the recycled content affects the material properties and safety of these polymers. The objective of this research was to investigate how material properties changed as commodity recycled material is incorporated into commercial products, and if these changes can be modeled. Post-consumer recycled (PCR) linear low-density polyethylene (LLDPE) feedstocks were blended with virgin LLDPE to create 0, 20, 40, 60, 80, and 100% wt/wt PCR sample sets. The recycled feedstocks contained either exclusively calcium carbonate or a blend of calcium carbonate and carbon black pigments. The sample blends were extruded on a Wayne single screw extruder into film and sheet. Samples were evaluated using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), ultraviolet-visible (UV-Vis) and fluorescence spectroscopy. Extractions in nhexane and xylene were performed according to Code of Federal Regulations (CFR) Title 21, B, Part 177.1520 for regulatory compliance with direct food contact applications. Results of this study suggest the potential for modeling of recycled content in pigmented polyethylene, particularly using ultraviolet spectroscopy, and that post-consumer recycled material may be safely incorporated into food contact applications.

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The Authors

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