Properties of polylactic acid and biochar-based composites for environment-friendly plant containers

Traditional, petroleum-based plastics are known to linger in the environment for years due to their non-biodegradability and non-sustainability, eventually fragmenting into microplastics and contaminating waterways and agricultural systems. Therefore, many researchers have focused on bio-based and biodegradable polymers, such as polylactic acid (PLA). Biochar, a byproduct of the bio-fuel production process, has been investigated as a filler to reduce the amount of PLA used and improve mechanical properties. This research focuses on effect of biochar amount on PLA composites and the impact of individual additives consisting of polyethylene glycol, STRUKTOL® (a plasticizer), and cork particles. It was found that the cork-based composites (51-54 MPa) improved tensile strength more than both of the plasticizer-based composites (41-46 MPa). While the scanning electron microscopy images showed some aggregation in the 10 wt.% biochar composite, the cork composites (1 and 3 wt.%) showed slightly less aggregation than other composites. Additionally, analysis revealed high carbon (81%) and fixed carbon (74%) concentrations, respectively, in the hardwood-derived biochar, indicating potential for carbon sequestration. • High biochar carbon content for better carbon sequestration • Cork composites produced comparable tensile strength to 10 wt.% biochar composites • Smoother tensile breakage for additive-based composites compared to biochar-based • No significant degradation seen within processing temperatures for all composites • Biochar and cork additives discouraged crystal nucleation