Thermal decomposition behavior of 3D printing filaments made of wood‐filled polylactic acid/starch blend

Dynamic thermogravimetric analysis under nitrogen environment was used to understand the thermal decomposition process of 3D printing filaments made of wood‐filled polylactic acid (PLA)/starch blend. The characteristic temperatures and apparent activation energy (AAE) of the filaments with various starch contents were calculated with well‐known kinetic models by Friedman, Flynn–Wall–Ozawa, Coats–Redfern, and Kissinger. With the increased starch content in the filament, the onset thermal decomposition temperatures of the filaments decreased gradually from 272.4 to 155.1°C. The thermal degradation degree became smaller, and the transitional temperature interval became larger with increased starch proportion. The AAE values of the three types of filaments with different starch ratios varied between 97 and 114 kJ/mol, depending on material composition and method of calculation. The four kinetics methods provide complementary techniques for analyzing thermal stability behavior of composite materials. The improved understanding of thermal decomposition behavior of PLA‐starch‐wood composites can help develop PLA/starch‐based filaments for 3D printing. Apparent activation energy (AAE) is the minimum energy required to change from ordinary molecules to activated molecules when reactants must collide effectively to reach the activation state. In this study, the AAE values calculated from a given kinetic model were generally in a similar range for the three types of PLA‐Wood‐Starch composites with different starch ratios (up to 20%), and they were observed to be mainly in a ‘band’ shape between 97 kJ/mol and 114 kJ/mol.