Hydrophobization of cellophane and cellulose nano-fibrils films by supercritical state carbon dioxide impregnation with walnut oil
Jari Vartiainen, Jani Pelto, Timo Kaljunen and Eija Kenttä
Bio-based films are typically sensitive towards moisture which limits the industrial applicability. In this study the cellulosic films produced from cellulose nanofibrils and cellophane were treated using supercritical state carbon dioxide impregnation with hydrophobic polyunsaturated oil mixture (walnut oil). The effects on surface hydrophobicity with cellophane films were clear and indisputable. Water contact angles of non-treated cellophane, walnut oil impregnated and further 1,6-hexanediol dimethacrylate crosslinked films were 62, 82 and 91°, respectively. Also the moisture absorption and water vapour transmission rate as well as oxygen transmission rate at 80% relative humidity decreased as a result of supercritical state carbon dioxide impregnation. Water vapour transmission rate of walnut oil impregnated cellulose nanofibrils film decreased by 30% as compared to non-treated film. Based on the FT-IR analysis and surface roughness measurements the walnut oil penetrated better into the structure of cellophane as compared to CNF film. The developed hydrophobization method can be exploited in strengthening the position of cellulosic films in high performance film applications.
Nordic Pulp & Paper Research Journal (NPPRJ) is an international scientific magazine covering science and technology for the areas of wood or bio-mass constituents, pulp and paper and including new fiber-based materials, recovery and by-products from pulping processes, bio-refining and energy issues. Articles meeting required scientific standards are accepted from any continent. Open Access: Articles not available through Gold Open Access may be purchased by credit card as a pdf file, to be downloaded within 24 h after ordering, at a price of 22 EUR per article. (Value added tax may apply depending on your location, which you enter at payment logout.) Such articles have Green Open Access, i.e. authors may share articles on their personal non-commerical homepage immediately after publication on the website and download them to non-commercial hosting platforms one year after publication in a full issue of NPPRJ. ISSN: 0283-2631