A potential problem with the foaming of PLA is that its melt viscosity and melt elasticity may be limited owing to its typically low molar mass.14,15 Moreover, like other polycondensates, PLA is sensitive to hygrothermal degradation during melt processing, which may lead to further decreases in molar mass.16 A chain extender was therefore used to increase the molecular weight by linking the reactive hydroxyl or carboxyl end-groups to form a branched architecture,17,18 and hence improve the foamability of the PLA/MFC.19–21