Abstract:

Objective　To prepare a new artificial bone material by in situ polymerization of polylactic acid and nano-hydroxyapatite.    Methods    According to a specified ratio (the mass fraction of nano-hydroxyapatite respectively was 0, 10%, 20%, 30%, and 40%), polylactic acid and nano-hydroxyapatite were composed by in situ polymerization, followed by the testing of material parameters, including mechanical, ultrastructural, dispersional features in vitro. The degradation rate of composite material was detected.   Results  With the increase of n-HA content, the tensile strength of composite material decreased, but the elastic modulus increased. 20% of nano-hydroxyapatite content, made the best bending strength of composite material (156.8 MPa).  SEM scan showed that, the fracture surface of pure PDLLA was relatively smooth; 10% of nano-hydroxyapatite content induced obvious dimples on the fracture surface. 20% nano-hydroxyapatite content induced uneven fracture surface, with a large number of dimples. However, 30% of nano-hydroxyapatite content made the fracture surface more flat. PH values of degradation liquid gradually reduced, as well the mechanical strength, following the extension of degradation.   Conclusions    Artificial bone material with 20% nano-hydroxyapatite content is ideal for its better mechanical properties and degradation properties.

Key words: Polylactic acid, Nano-hydroxyapatite, Artificial bone