Abstract:
Hydroxyapatite is a ceramic biomaterial that mimics the mineral composition of bones
and teeth of vertebrates. Hydroxyapatite can be synthesized from various chemical
methods. However, most are non-economical and does not have sufficient biological
properties as natural Hydroxyapatite in human bones. Cow bone waste is rich in
biocompatible Hydroxyapatite as a natural source. The load bearing ability of pure
Hydroxyapatite is very poor and it has limited its application as a bone grafting material.
Polylactic acid is a biocompatible, biodegradable, and bioresorbable polymer which can
be used to reinforce pure Hydroxyapatite to improve its mechanical properties. This study
investigated the change of mechanical property of pure Hydroxyapatite when it is mixed
with a varying ratio of Polylactic acid to form Hydroxyapatite-Polylactic acid composite.
High purity Hydroxyapatite was extracted from cow bones using the thermal
decomposition method by sintering at 900 ºC for 3 h. The composites were prepared by
blending Hydroxyapatite with Polylactic acid in various ratios with and without maleicanhydride compatibilizer. The resulting composite blends were subjected to tensile tests
separately with three replicates per blend. The thermal-gravimetric analysis was
performed to determine the purity of cow bone derived Hydroxyapatite in comparison to a
commercial Hydroxyapatite sample. 30% Hydroxyapatite loading composite blend with
4% maleic-anhydride has increased the tensile strength of the composite by about 7-folds.
Scanning electron microscope shows, the interfacial adhesion between Hydroxyapatite
and polylactic acid was increased by the addition of maleic-anhydride resulting in
improved mechanical properties. Fourier-transform infrared spectroscopy, X-ray
diffraction, and Thermal-gravimetric analysis show that derived Hydroxyapatite has
similar material properties as commercial hydroxyapatite. The prepared composite has the
potential of using bone drafting applications in humans.
Keywords: Hydroxyapatite, Polylactic acid, Maleic-anhydride, Bone grafting
biocomposites
