Environmentally friendly lignocellulose nanofibres from barley straw

Due to the environmental awareness in our society, this paper explores the possibility of obtaining high value-added products from agricultural wastes, such as cereal straw. The raw material chosen for this study was barley straw, which was pulped by a Specel^® pulping process. This process uses soda (7% on oven dried material) as reagent. The chemical composition of both barley straw and unbleached pulp was determined through different parameters (alcohol extractives, α-cellulose, hemicelluloses, lignin and ash). Lignocellulose nanofibres (LCNF) were obtained by subjecting the pulp to mechanical pretreatment, followed by a high-pressure homogenizer step. The produced LCNF were characterized with regard to the nanofibrillation yield, viscosity, cationic demand and carboxyl content. The LCNF were added to a papermaking slurry based on virgin eucalyptus (bleached Kraft hardwood pulp), in amounts of 1, 3 and 5% as reinforcement. Paper sheets were made and characterized with regard to their mechanical properties. The results indicated that paper strength was improved after the addition of LCNF.