MICROCRYSTALLINE CELLULOSE REINFORCED CHITOSAN COATING ON KRAFT PAPER

Paper is widely used in the packaging sector. Water vapor barrier and water resistance properties of packaging paper need to be improved by changing the wettability of its surface with sizing agents or through coating with hydrophobic materials, such as paraffin wax, polyethylene, poly(ethylene terephthalate) and poly(butylene terephthalate). In this study, a biodegradable coating was applied on kraft paper. The application of chitosan as a coating on kraft paper sheets could be an alternative to commercial synthetic polymer coatings. Chitosan with microcrystalline cellulose (MCC) was used to coat kraft paper sheets. The different concentration of chitosan and MCC were evaluated. The application of 1% chitosan (4.7 g/m(2)) alone lowered the water vapour permeability rate (WVTR) by 41.1%, the water absorption capacity (Cobb test) by 54.9%, while porosity decreased twice. An increase in chitosan concentration further improved these properties significantly. The addition of 1% MCC to 1% chitosan further reduced WVTR, porosity and Cobb(60) value. Also, a slight increase in the papermaking properties of coated paper was observed. MCC added to the chitosan coating increased the gloss value of the coated paper sheet. The addition of protein from leather mill wastes to the chitosan coating, instead of MCC, also improved these properties. However, coating both sides of the paper did not have the same effect.