Blends of poly(L-lactide) and poly(L-lactide-co-trimethylene carbonate) as promising materials for bone and cartilage tissue engineering

The aim of this work was to evaluate the properties of polymer blends of poly(L-lactide) and poly(L-lactide-co-trimethylene carbonate) 15/85 and to select two compositions to be used to prepare the materials for bone and cartilage tissue engineering. PLLA and PLLATMC as the polymers with significantly different mechanical properties could be used to prepare a wide range of polymer blends. They were investigated by ultimate tensile strength and Young modulus measurements. Considering similar mechanical properties to these types of human tissues PLLA:PLLATMC 80:20 and 30:70 blends have been chosen as appropriate materials for bone and cartilage engineering, respectively. The materials were examined by thermal analysis (thermogravimetry and differential scanning calorimetry), ATR-FTIR spectroscopy and surface analysis (roughness and contact angle measurements). Miscibility of two polymers was discussed. High thermal stability of the blends allow to process them by fused deposition modelling which is one of the most promising methods for the manufacturing of computationally designed scaffolds. Based on the results of thermal analysis at least partial miscibility of PLLA and PLLATMC in the examined blends is indicated. Detailed interpretation of ATR-FTIR spectra let to distinguish the polymers despite their structural similarities. Surface properties of the materials depend on the preparation method and on their form.