抄録
Recently, hydroxyapatite (HA) particle filled PLLA composite has been developed as a bioabsorbable bone fixation material to improve the bioactivity of the current PLLA implants used in oral and orthopedic surgeries. In this study, four kinds of HA fillers of different shape were used to fabricate HA/PLLA composites, and their fracture toughness values were evaluated. The result exhibited that the highest fracture toughness is induced by the micro-particle filler, while addition of the nano-particle filler to PLLA matrix leads to the lowest fracture toughness. Scanning electron micrography of the fracture surfaces showed that the highest fracture toughness of the microparticle filled composite is caused by debonding at the HA/PLLA interfaces and extensive local plastic deformation in the surroundings of the HA particles. On the contrary, the nano-particle filled composite having the lowest fracture toughness exhibits a flat smooth fracture surface, corresponding to low resistance to fracture.
