High strength chitosan rod prepared via LiOH/urea solvent through centrifugation induced orientation processing

Chitosan material is a promising candidate for bioabsorbable internal fixation devices, owing to its biocompatibility, biodegradability and versatility in orthopedic treatment. However, mechanical strength of existing chitosan rod materials is still unsatisfactory. In this study, chitosan rods with excellent mechanical performance had been prepared via a novel solvent, i.e. LiOH/urea solvent. The bending strength of chitosan rod prepared via LiOH/urea solvent could reach 450.2 MPa, which is over 300% higher than chitosan rods prepared via acidic solvent. Reasons behind the high bending strength of chitosan rods could be summarized in two aspects. Firstly, the gelation process of chitosan LiOH/urea solution is distinct from that of traditional acidic chitosan solution, which endows the material with homogeneous network structure. Secondly, due to the state of macromolecules in the solution, centrifugation processing can generate flow orientation in the material. Resulted from unique characteristics of chitosan LiOH/urea solution, the improvement of strength had made the novel chitosan rod a promising candidate of biomedical device for bone fracture internal fixation.