Technology for Processing Composite Materials Based on Polylactide Using 3D Printing: Properties and Structure

Polylactide (PLA) is one of the promising polymer materials for use in various medical fields due to its properties such as biocompatibility and biodegradability, and PLA is also the most used material for 3D printing. The creation of various medical products with complex geometric shapes is possible due to the use of additive technologies. PLA is modified by biocompatible fillers such as calcium hydroxyapatite (CaHA) to improve compatibility with bone tissue. CaHA is one of the sought-after mineral components for the creation of materials intended for the reconstruction of bone defects. In this paper, the technology of processing of polymer composite materials based on polylactide and calcium hydroxyapatite (CaHA) as a filler to create filaments used in 3D printing is examined. It is shown that the addition of CaHA leads to an increase in the elastic modulus by 47% and in the compressive strength at 25% relative strain by 27% compared to the original polymer. PLA samples obtained by extrusion and 3D printing are studied to select the optimal method for producing composites based on PLA and CaHA. It is shown that the improvement of the physical and mechanical properties of the material with low porosity is achieved using the 3D printing method with a filling degree of 80%. The peaks at 565 and 601 cm^–1 related to CaHA of the PLA-based composite containing 20 wt % CaHA are recorded using IR spectroscopy methods, but they are not confirmation of chemical interaction between PLA and CaHA. The SEM method shows that the fillers are poorly wetted by polylactide and therefore CaHA particles are located in PLA bubbles. In addition, agglomeration of the filler powder is visible, which leads to a decrease in the tensile strength of the material.