Manufacturing of high-performance nano/microcellular expanded PLA bead foams

In this study, expanded polylactide (EPLA) bead foams were produced with cellular morphology ranging from nanocellular to microcellular. This was achieved by using bead foaming technology while a double crystal melting peak structure was generated. The high melting peak crystals generated during the gas saturation played an important role on controlling the cell size and expansion ratio of the foamed beads. As the amount of high melting peak crystals increased, the cell sizes were reduced to around 350 nm while the expansion ratio was around 3-fold. In other words, the induced perfected crystals significantly promoted the heterogeneous cell nucleation while hindering the cell growth. On the other hand, with the reduced amount of these perfected crystals, the cell sizes were increased to around 15 μm and the expansion ratio of the foamed beads increased to 30-fold.