A strong, hydrophobic, transparent and biodegradable nano-lignocellulosic membrane from wheat straw by novel strategy

Wheat straw is a potentially natural material for production of bio-composites due to its chemical composition. Lignin, cellulose and hemicellulose are closely connected in wheat straw and difficult to separate for nano-lignocellulose in high valuable application. The work presented a clean and simple way to prepare biodegradable nano-lignocellulosic membrane with high mechanical strength and water barrier property using nano-lignocellulose derived from wheat straw. Wheat straw was soaked in aqueous solution of urea at 90 °C for 24 h and fibrillated with boiling to obtain urea treated nano-lignocellulose (UNLC). Moreover, starch soluble (SS) latex was mixed with the UNLC slurry for binding the reinforcement for preparing the novel membrane (UNLC/SS). High speed centrifugation realized stratification of the chemical composition from wheat straw. Waxy and lignin as hydrophobic component was located at the surface of the developed membrane, which improved the water barrier property of the membrane. Water contact angle of the lignocellulosic membrane was beyond 110°. The hydrogen bond formation between the starch and cellulose increased the mechanical property of the novel biodegradable membrane. The tensile strength of the nano-lignocellulosic membrane increased from 7.6 MPa to 27.4 MPa. As the high strength, hydrophobic, transparent, biodegradable performance, the bio-composite membrane has many potential industrial applications.