Novel bio-antifelting agent based on waterborne polyurethane and cellulose nanocrystals.

Novel nanocomposites made from cellulose nanocrystals and waterborne polyurethane were employed as wool antifelting agents. The cellulose nanocrystals, prepared by acid hydrolysis of cellulose microcrystalline, are in rod form with lengths of 70-150 nm and diameters of 10-20 nm in aqueous suspension, respectively. After the two aqueous suspensions were mixed homogeneously, cellulose nanocrystal reinforced polyurethane composite (nanocomposite) films were prepared and evaluated by means of transmission electron microscopy, scanning electron microscopy and dynamic mechanical analysis. Then the nanocrystal films were applied onto surfaces of wools by a pad-dry-cure process with nanocomposites containing different cellulose nanocrystal contents. The results indicated that with increasing cellulose nanocrystal content from 0 to 1.0 wt%, the area-shrinking rate of the treated wool fabrics was decreased from 5.24% to 0.70%, and the tensile strength of the fabric was increased by 14.95% and decreased about 44% use of waterborne polyurethane.