Assessment of innovative PLA biopolymer compositions with plant waste fillers

•Innovative thermoplastics bio-resorbable composite materials based on polylactic acid (PLA) with onion and buckwheat husks were proposed.•Composite materials with addition of 10, 20, 30 wt% of onion or buckwheat husks were prepared by extruding PLA with the filler following by pressing using a hydraulic press with a pressure of 10 kN.•Mechanical and thermo-physical properties of the composite materials were tested, with a particular attention to their degree of crystallinity.•10% of filler addition has a beneficial effect on an increase in elongation and degree of crystallinity of composite material.