Chitin added to three types of polyurethane resins including hydrophilic, water in oil (w/o) emulsified, and wet-coagulated polyurethane resins for cast films and coated fabrics was investigated in this study The results showed that adding chitin to the hydrophilic and wet-coagulated polyurethane resins can effectively increase the water vapor permeability of the cast films or nylon coated fabrics. For the w/o emulsified polyurethane coated fabrics, however, this increase was not detected. These observations can be readily explained by the microstructural variations which create homogeneous or irregular pores, as evidenced by the scan ning electron microscope pictures
