Ratan Singh

The present technology provides processes for cross-linking cellulose ethers under mild conditions. The processes include exposing a substantially dry cellulose ether film to a polyisocyanate to provide a cross-linked cellulose ether film, wherein the substantially dry cellulose ether film comprises alkoxide groups on the cellulose. The resulting cellulose ether films are highly cross-linked by polyurethane linkages and may be used as membranes in a variety of applications.