Development of 3D Printing Filament from HAp Reinforced PLA/PCL Biocomposites Using Melt-blending Method

Additive manufacturing technology has made prototyping more time and cost efficient, allowing more bold, new ideas to be 3D-printed and tested out. This technology can be applied throughout the medical line, where medical equipment and surgical implants can be 3D-printed. Tissue Engineering (TE) has the potential to significantly improve the recovery rate of the damaged tissues and organs but is currently still in its early developing years, as more research is being conducted in this area. One of the limitations of TE at this stage is finding the right biomaterial and its suitable fabrication method of the scaffold, which is the external support that aids tissue regeneration. A scaffold can be fabricated by various methods, examples include fused deposition modelling (FDM) 3D-printing, solvent casting, selective laser sintering, etc. This project focuses on the 3D-printing aspect. The main challenge of this project is to produce a homogeneously mixed biocomposite material composed of polylactic acid (PLA) as the main matrix, mixed with polycaprolactone (PCL), and reinforced with hydroxyapatite (HAp). PLA is promising as it has good mechanical properties like material strength, but it is very rigid. Adding PCL into the matrix helps to improve the flexibility of the polymer. HAp helps with the biocompatibility of the biocomposite material. The process known as melt blending is reportedly the preferred method for mixing thermoplastic matrix with clay reinforcements to form nanocomposites and has been reported to increase the thermal stability of a polymer. However, these claims about the melt blending processes did not come specifically from the process of mixing PLA/PCL-HAp biocomposite. Therefore, this research would like to use melt blending method to prepare the biocomposite, and to see if this method is able to prepare a homogeneously mixed PLA/PCL-HAp biocomposite. The ingredients will be melt-blended and extruded into a 3D-printing filament using the Brabender internal mixer, which will be able to produce a torque in the pair of mixing screws. As the biocomposite material becomes homogeneous, the torque produced will become consistent as the mixing screws are spinning. Once a homogeneous biocomposite is obtained and extruded, the filament will then undergo differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) tests to investigate the thermal properties of the biocomposite material. The main thermal properties are the degradation temperature and the temperature at which the PLA/PCL-HAp biocomposite is able to flow while maintaining its desired form when it solidifies. A rheology meter will also be used to investigate the rheological properties, mainly the melt flow index of the biocomposite.