کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1430492 | 987204 | 2009 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Preparation and characterization of dense nanohydroxyapatite/PLLA composites Preparation and characterization of dense nanohydroxyapatite/PLLA composites](/preview/png/1430492.png)
Synthetic bone graft substitutes based on PLLA have been largely studied during the past decade. PLLA/hydroxyapatite composites appear as promising materials for large bone defect healing. In this study dense PLLA/nano-hydroxyapatite composites were prepared by hot pressing. Dense samples were investigated rather than porous scaffolds, in order to shed light on possible correlations between intrinsic mechanical properties and nano-hydroxyapatite concentration. Hydroxyapatite deagglomerated by wet attrition milling, and further dispersed into chloroform was used (median diameter = 80 nm). Particle size distribution measurements and transmission electron microscopy show evidence that particle size and dispersion are maintained throughout the successive steps of composite processing. Mechanical properties were tested (uni-axial and diametral compression tests) as a function of nano-hydroxyapatite content. Increasing concentrations of nano-hydroxyapatite (0, 25 and 50 wt.%) increase the Young's modulus and the mechanical strength of the composite; at the same time, the failure mechanism of the material changes from plastic to brittle. Young's modulus over 6 GPa and uniaxial compressive strength over 100 MPa have been achieved. These values expressed in terms of intrinsic tensile and shear strengths indicate that 50 wt.% nano-hydroxyapatite containing samples develop properties comparable to those of cortical bone. PLLA/nano-hydroxyapatite composites are thus promising candidates to develop bioresorbable porous bone substitutes showing superior mechanical performance.
Journal: Materials Science and Engineering: C - Volume 29, Issue 1, 1 January 2009, Pages 172–177