Degradation kinetics and volatile identification in poly(lactic acid), aloe vera, and polyester polyol biocomposites

Abstract

Polymers derived from renewable sources and sustainable processes have been investigated as alternatives to petrochemicals, aiming to improve performance and avoid environmental damage. In this context, poly(lactic acid) (PLA) is a renewable thermoplastic source, used in biocomposite matrices. This study investigated the thermal and mechanical properties, kinetics, and degradation mechanisms of PLA‐based biocomposites with addition of aloe vera (AV) extract and Priplast™ (Pr). PLA/AV/Pr biocomposites exhibited hardness and heat‐deflection temperature (HDT) similar to PLA. Thermogravimetry (TG) and TG coupled to Fourier transform infrared spectroscopy (TG‐FTIR) measurements showed that PLA/AV/Pr compounds presented higher thermal stability than PLA. Kinetic study, using the isoconversional models of Friedman, Kissinger‐Akahira‐Sunose (KAS), and Ozawa‐Flynn‐Wall (OFW), demonstrated that PLA/AV/Pr compounds have higher degradation activation energies than PLA, with R2 and R3 mechanisms acting competitively. Gases released during degradation were identified as H2O, CH4, CO2, CO, lactide, and acetaldehyde. The PLA/AV/Pr biocomposites exhibited superior mechanical properties and thermal stability compared to neat PLA.