Composite of Hydroxyapatite Nanoparticles- Poly(ε-caprolactone-co-lactide)

Hydroxyapatite nanoparticles were surfacegrafted with ε-caprolactone (ε-CL) by the ring-opening polymerization, and different quantity of lactides were segmented on the particles. The structure of the composite is characterized by TEM, FT-IR, 1H-NMR and 13C-NMR. The results indicate that HA has been dispersed homogeneously in the composites and kept original acicular or rod morphology. With the feeding ratio of ε-caprolactone to lactide (molar ratio) increasing, the molar ratio of caprolactone units to lactide units in the copolymer increases. No transesterification between caprolactone and lactide is observed. The transesterification of lactide occurs, but the segment of PLA in the copolymer gives priovity to isotactic sequence mainly.