Carboxyl functionalised MWCNT/polymethyl methacrylate bone cement for orthopaedic applications

Area of Science:

• Biomaterials Engineering
• Nanotechnology in Medicine
• Orthopaedic Materials Science

Background:

• Orthopaedic bone cements are crucial for implant fixation.
• Enhancing mechanical and thermal properties of bone cements is an ongoing challenge.
• Multi-walled carbon nanotubes (MWCNTs) offer potential for material reinforcement.

Purpose of the Study:

• To investigate the effects of incorporating carboxyl functionalised MWCNTs (MWCNT-COOH) into Simplex P™ bone cement.
• To evaluate the impact on static and fatigue mechanical properties.
• To assess changes in thermal and polymerization characteristics.

Main Methods:

• Incorporation of MWCNT-COOH at 0.1 wt% into Simplex P™ bone cement.
• Testing of static mechanical properties (bending strength, modulus, fracture toughness).
• Fatigue testing to determine cycles to failure and fatigue performance index.
• Thermal analysis to assess necrosis index.
• Polymerization property analysis (onset, duration, energy, area).
• Raman spectroscopy for chemical interaction and strain analysis.
• Raman mapping for dispersion assessment.

Main Results:

• Significant improvements in bending strength (42%), modulus (55%), and fracture toughness (22%).
• Enhanced fatigue properties, with a 64% increase in cycles to failure and 52% in fatigue performance index.
• Reduced thermal necrosis index values (28-27%) at critical temperatures.
• Modified polymerization kinetics: delayed onset (58%), increased duration (52%), higher peak energy (672%), and increased peak area (116%).
• Raman spectroscopy confirmed chemical interaction and increased compressive strain on MWCNT-COOH.
• Homogenous dispersion of MWCNT-COOH was observed.

Conclusions:

• MWCNT-COOH incorporation significantly enhances mechanical and fatigue performance of Simplex P™ bone cement.
• The addition of MWCNT-COOH positively influences thermal properties and polymerization kinetics.
• Evidence of chemical interactivity between MWCNT-COOH and the cement matrix suggests improved load transfer mechanisms.
• These findings indicate MWCNT-COOH as a promising additive for advanced orthopaedic bone cements.