Study On CS Fiber/HA/PLLA Ternary Composites

Chitosan (CS) is a kind of natural polysaccharides from animals and plants, with sterilization. antiphlogistic. prevent adhesion, maintaining ecological balance and collaborative organizations repair, widely used, in biomedical fields. Hydroxyapatite (HA) has good biological activity and bone conductivity, can shape bone formation key. get a lot of apply in bone alternative materials. Polylactide have excellent biocompatibility. biodegradation, its final degradation products are lactic acid which is excluded by normal metabolism in vitro. But because of its degradation products become acidic acid concentration, which can cause organization of local aseptic infection, limit application of in the tissue repair areas. This thesis design PLLA CS/HA/PLLA materials, which have the biological activity of CS and HA. but also the biodegradation of PLLA. while in degradation process CS and HA can counteract the acidic effects polylactic acid cause.For composites, reinforcing interface layer of material surface and the substrate material has very big effect in its formed performance. First, this article modify a layer of polylactic acid through the surface intercept method in CS fiber surface.then mould compound with the PLLA. investigate thoroughly effect of CS/PLLA composite materials mechanics properties about modification of chitosan fibers and the different contents of CS fibers. The results show that surface interception can maintain the formation better, chitosan fibers fiber surface intercept polylactide successfully. After the surface modification of CS fibers.which become rougher in composite material, and interface clearance is not apparent with PLLA. improved the compatibility with PLLA materials matrix. In CS/PLLA composite materials, when modified chitosan fiber content is 2%. bending strength is the highest for 140MPa. bending modulus for 4.14 GPa. Then in this paper HA are grafted polylactic acid through a solution polymerization. HA after stem grafting (g-HA) is moulded will PLLA and get composite materials. Research results show that g-HA scatter better in PLLA matrix, reducing the reunion of HA before modification in the PLLA matrix. improving the interface bonding between HA and PLLA. When g-HA content is 5% in the composite, the bending strength of composite materials is 148MPa and bending modulus is 4.50 GPa, which is a maximum.On this basis, we prepare CS/HA/PLLA termary composite material, and probe into degradation performance study in vitro. Comparing modification CS/PLLA composite materials and g-HA/PLLA composites, when modified chitosan fiber content is 2%. g-HA content is 15% in the composites, bending strength is 153MPa which is highest, improving the mechanical properties of composite. SEM show that i CS fiber of modification and g-HA in composite material have a good dispersion. In vitro degradation experiment results show that compared with the pure PLLA. CS fibers and HA particles counteracted degradation medium acidic metabolites, and lowered the catalytic effect of material, to improve the pH value, the material weight loss slowing quickly, can reduce the occurrence of aseptic inflammation.