Preparation And Characterization Of The Chitosan Intramedullary Nails

Layer structure is a perfect structure through nature selection. Hollow and solid chitosan intramedullary nails with layer-by-layer structure were prepared by in-situ precipitation in this thesis. The structure and properties of the hollow intramedullary nails was discussed. The influence of heatment on the properties of solid intramedullary nails was also discussed.1. In-situ precipitation method was used to prepare chitosan rod by using chitosan membrane as template and NaOH as precipitant. Because of the drying stress, the outer and inner surface is smooth. SEM observed show that the structure of nail is assembled in the order of layer-by-layer. The mechanism for preparing the intramedullary nail was discussed detailedly.2. Effcts of boss ratio on the mechanical properties of intramedullary nail was discussed. The factors were listed which influence the boss ratio. It was found that there is a linear relationship the precipitation time and the boss ratio, on the case that other factors are constant.3. The initial mechanical properties of bending strength and modulus of intramedullary nail are 119.51M Pa and 3.55G Pa respectively, which basically meet the biomechanical requirement.4. Dissolvability, intrinsic viscosity, XRD, TGA and FRIT of the heated solid chitosan intramedullary nail were tested. All of the results show that heat-induced reactions in chitosan may involve the -NH2 groups and the formation of crosslink.5. Mechanical strength of heated chitosan intramedullary nail was tested. The results show that heat improved theintramedullary nail's strength which increased with the temperature increased and reached the maximum at 140℃.6. Water absorption of the heated chitosan intramedullary nail was tested. The results show that water absorption decreased with the increase of the temperature.