Preparation And Properties Of Chitosan-based Bionic Gradient Materials

This study is based on horizontal comparison of the variety of natural materialssuch as bamboo, shells, teeth, bones and other natural materials which have excellentproperties, reference, induction and imitate what they have in common in the internalstructure, and design the chitosan-based biomimetic composite rods with gradientstructure, in order to improve the mechanical performance of the composite.The acid-base neutralization method is applied to prepare the graded materials,in which chitosan is used as the matrix and CaCO3as the reinforcing phase. Afterseveral processes such as the calculation of the relative component, the preparation ofthe semi-permeable membrane, configure the mixed solution, precipitation andconstant temperature drying step, we finally get the gradient composite Bionic bar.Structure and property of the material such as the crystalline structure, the wet gelstick hardness characterization, water absorption behavior, bending characterization,and compression characterization are measured by X-ray diffraction, mechanical testsand other measurement. Experimental results indicate that the composition,morphology and property varied gradually in the composite rods. The analysis resultsshow that the bionic gradient structure composite bar with the outer dense and innersparse structure obtained after the drying step, and the gradient material has noobvious cracks and other defects that commonly found in the preparation process ofother graded materials. The content of CaCO3increased gradually while chitosandecreased along the radius direction, which makes its mechanical strength far greaterthan the sample with the same composite material made under the same conditionsand that made from pure material. With high strength, good histocompatibility anddegradation in human body, the obtained gradient materials as well as the preparationmethod employed in this study is expected to be used in human medicine for bonerepair surgery.