BaSO4/PLLA nanocomposite material for coronary stent application
Chow, Wei Shoon
Date of Issue2016
School of Materials Science and Engineering
This final year project investigated the effect of adding barium sulfate (BaSO4) nanoparticles on the mechanical properties of poly-l-lactic acid (PLLA) such as ultimate tensile strength (UTS), percent elongation at break, Young’s and compressive modulus so as to assess its suitability as a coronary stent. In this study, nanoparticle loading, size, and functionalization were taken into consideration so as to understand its effects on tensile and compressive properties. Tensile tests were conducted on BaSO4/PLLA nanocomposite fibres while BaSO4/PLLA nanocomposite tubes were evaluated with a compression test. Results highlighted that the addition of BaSO4 nanoparticles did raise the mean Young’s Modulus of BaSO4/PLLA fibre by a range of 11.68% to 17.61% and 8.94% to 21.70% for 20nm and 100nm BaSO4/PLLA respectively up till a certain particle percentage weight loading before regression occurs. UTS of BaSO4/PLLA fibre followed a similar trend to Young’s modulus and was increased by 62.23% to 118.10% and 66.48% to 83.03% for 20nm and 100nm BaSO4/PLLA respectively. However, percent elongation at break was found to be lower than pure PLLA fibre across all tested particle loadings. Compressive modulus increased with the addition of BaSO4 nanoparticles by 29.52% to 62.59%. Comparison between different sizes of BaSO4 nanoparticles in PLLA matrix did not yield notable trends or differences in tensile properties due to agglomeration of nanoparticles. Stearic acid (STE) functionalized BaSO4 in PLLA was then assessed to counter aforementioned issues but there was insignificance of Young’s Modulus and UTS increment over unfunctionalized BaSO4/PLLA. However, percent elongation at break did improve comparatively across all tested particle weight loading by 29.07% to 199.24%. In conclusion, with suitable conditions, the introduction of BaSO4 nanoparticles could possibly augment the mechanical properties of a biodegradable polymeric stent. Nevertheless, alternate forms of functionalization or fabrication tools with the ability to distribute nanoparticles uniformly should be explored to maximise the mechanical properties of BaSO4/PLLA nanocomposite material for coronary stent application.
Final Year Project (FYP)
Nanyang Technological University