Improvement of the hydrolytic stability of new flax-based biocomposite materials

New natural biocomposite materials were prepared from flax. Non-woven flax fibres material was chosen as a reinforcement and mucilage polysaccharides, extracted from flax seeds, were used as a matrix. Mucilages were extracted from two spring fibre-varieties, Aurore and Alizee. The matrix was crosslinked with epichlorohydrin (T = 70 °C, P = 50 bar, 4 h) in order to improve the water stability of the biocomposite. Glycerol was added as plasticizer. The composite was optimised with Alizee-mucilage extracted at 40 °C and with epichlorohydrin 8% wt/wt. Swelling in liquid water and sorption of water vapour were the lowest (120% and 53% for 97% of relative humidity, respectively) due to the high protein content that crosslinked with epichlorohydrin. The best mechanical performances were obtained (σB = 30 MPa, εB = 10%, E = 450 MPa) for the lowest crosslinker content (EP 4% wt/wt).