Preparation And Characterization Of Chitosan Rod

Chitosan (CS) had applied widely in biomedical field and the research mostly focused on ID and 2D materials such as membrane, fiber, microcapsule and so on. But few researches were on 3D materials as degradable implant. In this thesis 3D chitosan medical material were prepared by in-situ precipitation. The relation in process, morphology and properties of material was studied.1. In-situ precipitation method was developed to prepare chitosan rod by using chitosan membrane as template and NaOH as precipitant. Molding mechanism of CS congealation rod and the effects of base concentration, CS concentration and temperature on the molding were studied. The results showed that in the process of in-situ precipitation CS precipitated layer-by-layer in the template to form 3D layer CS congealation rod by acid-base neutralization of NaOH and the amino group of CS. When the process condition was well controlled, it formed homogeneous structure.2. Molecular weight, crystallinity and water absorption of CS before and after process were studied. It was found that the reduction of CS molecular weight was limited. The crystallinity decreased and water absorption of CS rod was still large. Morphology investigations indicated that CS rod prepared by in-situ precipitation was bi-axis tropism.3. Mechanical strength of CS rod was tested, and the effects of raw material, water content of CS rod and crosslinking modification with glutaraldehyde were discussed. The results showed that mechanical strength of CS rod improved as molecular weight increased with the same D.D. CS rod had good mechanical strength in dry state, but mechanical strength decreased greatly as water content increased. Toughness of CS rod crosslinked with glutaraldehyde increased drastically, and the modified rod showed tough rupture.4. Degradation in vitro of CS rod was studied. Results of weight loss and molecular weight change of CS rod degrading in phosphate buffered solution for 16w indicated that CS degraded very slowly.