The toughened and heat-resistant composites for additive manufacturing applications: The use of poly(lactic acid)/poly(butylene succinate) blends modified with natural fillers

This paper presents research focused on the preparation of a novel type of poly(lactic acid)/poly(butylene succinate) blend (PLA/PBS) dedicated to additive manufacturing via filament 3D printing, material extrusion method MEX. Standard PLA-based materials are often insufficient for engineering applications due to their low heat resistance (approximately 50 °C) and high brittleness. The main aspect of the novelty of the discussed research is the attempt to combine the concept of using PBS as an important material component, thermal treatment of finished parts, and the use of surface-modified natural fillers. In previous studies, these issues were not addressed within one comprehensive study. The first stage of the study was carried out to optimize the composition of the PLA/PBS system, while the second stage focused on the development of husk filler biocomposites with high shape accuracy and improved thermostability. The PLA/PBS (50/50%) material was used for further modification with buckwheat husk filler (BH), the surface of BH particles was additionally physically modified with ethyl cellulose (EC), cellulose acetate (CA) and poly(vinyl alcohol) (PVOH). The prepared samples were subjected to annealing to increase the thermomechanical performance. The result revealed that the elongation at break for PBS-modified materials reached over 30 %, compared to the initial 3%, while the reduction of tensile strength/modulus values reached only 25 %. The thermal resistance measured by head deflection temperature for annealed samples was close to 100 °C, compared to 60 °C for untreated materials. At the same time, the shape accuracy results did not differ significantly from the reference samples. Surface modification of the filler particles also indicates some favorable behavior; however, these values do not indicate high compatibilization efficiency. The conducted study revealed that the developed PL/PBS-based filament can be successfully used as the viable, tough, and heat-resistant alternative for MEX printing. • PLA/PBS-based blends were successfully used in filament-based 3D printing • The developed blend was used as the matrix for husk particle-based biocomposites • Annealing procedure was involved during the post-treatment • The elongation at break of PLA/PBS/BH materials reached > 30% • PLA/PBS/BH composites achieve an HDT of ≈100°C after annealing