Turning Hardwood Dissolving Pulp Polysaccharide Residual Material into Barrier Packaging

Birch chips were subjected to pilot-scale pre-hydrolysis under various sets of conditions to mimic a pre-hydrolysis step in a dissolving pulp process. The process generates residual process liquor, a wood hydrolysate, and the treated chips may be directly utilized in a dissolving process. The wood hydrolysates were rich in xylan and utilized in the production of fully renewable films that provide very good oxygen barrier function and mechanical integrity also at high relative humidity. Membrane filtration had an effect in enriching higher molecular weight fractions from the hydrolysates, but noteworthy, a hydrolysate used in the crude state without any membrane filtration performed just as well as upgraded fractions in forming films providing acceptable tensile properties and a good barrier against oxygen permeation.