Improved packaging performance of olive tree-based biochar-loaded poly(lactic acid) films

Petroleum-containing packaging materials have created serious ecological problems for the environment due to their resistance to biological degradation. In this context, the use of biodegradable films as alternative to packaging materials is gaining importance. Among various biopolymers, poly(lactide) (PLA) is an effective and durable material. However, the mechanical strength of PLA polymer is low. In addition, its vapor permeability is high, which limits the use of this material. Biochar (BC) is an additive that can be produced from many wastes and acts as a fertilizer in the soil. Adding it to the PLA material makes the packaging film completely compostable and improves its properties. In this study, biochar was synthesized from olive pruning waste by the slow pyrolysis method. Biochar was added to the PLA films in different ratios (5, 10, 15, 20 wt.%). The packaging properties of the films were investigated. Specific surface area (BET), biochar yield, and ash content, as well as tensile strength, swelling, water vapor permeability, and opacity of the films were determined. Owing to the high lignin rate and low volatile matter in the olive branch, biochar was produced with a yield of 29.75%. When the BC concentrations of the films increased, the water vapor permeability capacity gradually decreased from 4.43% to 1.36%. The maximum tensile strength value was obtained as 14.91 MPa for 5 wt.% biochar-loaded PLA films. © 2024 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria.