Document Type

Honors Thesis

Publication Date

Spring 5-2018

Abstract

From potato chips to chocolate bars, snack packaging requires materials that have excellent water vapor and oxygen barrier properties, good mechanical behavior, and good grease resistance. The most common material used in snack packaging is polypropylene (PP) layer that has been aluminum coated or metalized on one surface. The problem is not only that non-renewable petroleum is used to produce the plastic, but the production of aluminum requires large energy inputs and generates toxic wastes. In addition, this current packaging does not break down in the environment and cannot be recycled. This research is looking at using layers of cellulose nanofibrils (CNF) and water-barrier layers on paper as a replacement for current packaging materials. This replacement will make the packing recyclable and renewable without compromising the characteristic of water, oxygen and grease resistance. The estimated production costs are similar to the current materials.

This work is part of a three-year project. The part presented in this thesis is part of the first year that is mostly the bench scale work that includes: coating CNF layers on papers, coating water-barrier layers, and exploring different paper types. In addition, all samples were characterized in terms of coat weight, air permeability, water-vapor permeability, and water vapor transmission rate using standard methods.

A number of paper types were used, including one that had CNF incorporated into the paper structure and one that had a CNF layer applied on the wet end of a paper machine. Three different water based barrier coatings were applied at a range of coat weights. A key focus here was the water vapor transmission rate, that dropped to a low level with a couple of different formulations. Papers that were coated on both sides had water vapor transmission rates that were below our detection limit.

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