Preparation And Properties Of Cellulose / Polyurethane Blend Membrane

For softness, moisture permeability and other excellent properties, viscose, modal and other regenerated cellulose fibers are welcomed by consumers. However, regenerated cellulose fabric are easy to crease, so it’s not convenient for people to wear. For the high elasticity of polyurethane, by adding it to cellulose solution, the flexibility and wrinkle resistance of regenerated cellulose can be improved, which can provide a new way for the modification of cellulose.This paper used Lithium chloride/N,N-Dimethylacetamide as solvent system to prepare cellulose/polyurethane blend films. After exploring the influence of the blending ratio, the film-forming methods and the temperature of coagulation bath to the structure and properties of blend films, fibroin was added into the blend liquid, and the influence of the amount of fibro into blend films was studied. The structure of the blend films was investigated by infrared Spectroscopy(FTIR), scanning electron microscope(SEM), X-ray diffraction(XRD), and the mechanical properties, crease recovery properties, moisture absorption properties of the blend films were tested.The results demonstrated that the crystalline of cellulose wasn’t changed with the addition of polyurethane. However, the crystallinity of cellulose was decreased to some extent. In the blend films, there existed strong hydrogen bonds between cellulose and polyurethane macromolecules, which led to good compatibility between this two components. The blend films were transparent and homogeneous. The optimal process to make blend films was: m(cellulose):m(polyurethane)=10:2, used water as coagulation bath, the temperature of coagulation bath was 20℃. Compared with pure cellulose films, the breaking strength of cellulose/polyurethane blend films increased by 16.5%,the elongation at break increased by 43.2%, the crease recovery angle increased by 26.0%,absorption rate increased by 7.6%, and the moisture rate reduced by 8.7%.Then added fibroin into cellulose/polyurethane blend liquid, and the best proportion was m(cellulose): m(fibroin) = 10:1.5. Compared with pure cellulose films, the breaking strength of cellulose/polyurethane/fibroin blend films increased by 7.2%, the elongation at break increased by 34.5%, the crease recovery angle increased by 40.3%, absorption rate increased by 29.6%, and the moisture rate increased by 4.3%.The breaking strength and elongation at break of cellulose/polyurethane increased significantly. After adding fibroin, the moisture absorption and retention increased at the cost of a little strength loss. The preparation process can be chosen according to different needs. The comprehensive performance of cellulose/polyurethane blend films is excellent. This paper lays a good foundation for the preparation of the new regenerated cellulose fibers.