Effects of thermal annealing as polymer processing step on poly(lactic acid)

Thermal annealing as an additional polymer processing step or post-treatment processing step enables the structural changes of amorphous parts into crystalline parts. This paper investigates the feasibility of thermal annealing at 100 degrees C up to 90min used as an additional processing step to modify the crystalline structure and the thermo-mechanical stability of poly(lactic acid) (PLA). Moreover, the crystallization ability of PLA has been amended by the addition of 3wt% of wood flour and kaolin. The values of the degree of crystallinity and lamellar thickness determined by wide-angle-X-ray scattering showed that the thermal annealing of PLA samples modified with nucleating agents was an efficient processing step to increase the final crystallinity of PLA. Moreover, altered crystalline structure helped to improve the thermomechanical stability of PLA.