In this study, starch foams are obtained bymelt extrusion
in which water is used as blowing agent as it turns into steam
under temperature and pressure conditions of the extrusion.
To enhance the number of cells and to homogenise the
cellular microstructure, additives such as nucleating agents,
that is, talc, are used. PLA foams are obtained by melt
extrusion using a chemical blowing agent (called CBA) which
decomposes at the PLA melting temperature.