Extrusion Foaming of PLA-Based Nanocomposites: Effects of Different Nanofillers and Chemical Reagents on Foam Morphology

Poly(lactic acid) (PLA) foams have great potential for replacing synthetic polymer foams owing to their special properties such as biodegradability, biocompatibility and good mechanical performance. However, PLA has some drawbacks in common foaming processes to gain marketability. In this work, the PLA melt strength in extrusion foaming process was improved by adding different nanofillers, i.e. nanosilica, expanded graphite, pristine nanoclay and organoclay as well as chemicals including benzoyl peroxide and maleic anhydride grafted polyethylene. The morphological results and void content measurements show that the incorporation of the chemicals into PLA matrix comparatively causes better foam structural characteristics than nanofillers.