Structural, thermal and mechanical changes in poly(l-lactide)/hydroxyapatite composite extruded foils modified by CO2 laser irradiation

[Display omitted] •PLLA/hydroxyapatite foil was obtained using extrusion and film casting processes.•The composite was modified using CO2 laser infrared radiation.•CO2 laser radiation causes polymer crystallinity and molecular weight reduction.•The process can be used for selective modification of bioresorbable bone implants. The subject of the work is CO2 laser modification of poly(l-lactide)/hydroxyapatite (PLLA/HAp) composite for potential application in bone reconstruction. In the research we prepared composite foil based on PLLA with 10 wt% of HAp using twin-screw extrusion and film casting processes. The composite was modified using CO2 laser (λ = 10.6 µm) with the fluences of 79, 94, 110, 118, 141 J/cm2 (below the ablation threshold) and 164 J/cm2 (around the ablation threshold). The material was examined for changes in thermal (DSC) and structural properties (WAXS, ATR), molecular weight distribution (GPC), surface wettability and changes in tensile properties. Under the influence of CO2 laser modification, the degree of PLLA crystallinity was reduced, the molecular weight was lowered and the mechanical parameters decreased in proportion to the increase in applied fluence. The CO2 laser modification with the fluences higher than 94 J/cm2 influence on cold crystallization behaviour and the kinetics of α′-α transformation of PLLA during subsequent heating of modified composites.