Effect of 60Co irradiation on the properties of chitosan rod

Three dimensional layered chitosan rod with high bending strength and potential application as internal fixation of bone fracture was prepared by in-situ precipitation method. To evaluate the effect of 60Co irradiation on the properties of it, chitosan rod was irradiated at doses from 10 kGy to 200 kGy. FT-IR, Ubbelohde viscometer, conductometric titration, GPC, XRD, SEM and universal materials testing machine were used to monitor the changes in structure, morphology and mechanical performance. Results indicated that the chain scission effect obviously dominated in the radiation degradation of chitosan rod. With the increase of irradiation dose, the amount of C═O groups clearly increased, the deacetylation degree (DD), intrinsic viscosity and weight-average molecular weight (Mw) kept decreasing, and the crystallization peak and bending strength reached their maxima at the dose of 20 kGy. Chitosan rod irradiated at 20 kGy had a relatively higher and more stable bending strength of 132.3 ± 1.6 MPa. So it was selected as the model to study the lysozyme degradation of irradiated chitosan rod, showing a weaker hydrophilicity than the unirradiated chitosan rod, and almost the same degradation rate.