Abstract: The effect of NaClO effective chlorine dosage on the performance of starch and the subsequent composite films was explored. The composite films were fabricated with oxidized starch, polyvinyl alcohol (PVA) and glycerol (GL), which corn starch was used as raw material and nanocrystalline cellulose (NCC)/NaClO was applied as oxidation system. The carboxyl content, molecular weight, surface morphology, crystal structure, and the performance of composite films of the oxidized starch were characterized. The results showed that the oxidation degree of starch increased with increasing NaClO effective chlorine dosage, and increased by 1.17% with 10.0%(Significantly improved comparing with 0.36% of the carboxyl content of NaClO oxidized starch without NCC) with the assistance of NCC; When the amount of NaClO is 8%, the M_w and M_n were 97.33% and 97.27% lower than that of native corn starch. The surface was eroded and crystallinity was reduced after oxidation of starch. However, the films'transparency was improved (The maximum transparency is up to 78.50%). The increasing oxidation degree of oxidized starch contributed to the good performance of the composite film with high water resistance and the increase of the contact angle as well as tensile strength, whereas led to the decrease of the air permeability and tensile strain. When the amount of NaClO is 10%, the mass loss ratio of the composite film is 23.14%, the contact angle is 101.0° in 15 s, the air permeability is 0.10 cm³/(cm²·s), the tensile stress is 24.01 MPa, tensile strain is 2.14% and Young's modulus is 1 452.25 MPa.

Key words: corn starch, nanocrystalline cellulose, NaClO, oxidation, composite film