Solvent-Free Generation of Foamed Microcapillary Films with a Dual Network of Interconnected Pores and Internal Channels

A dual-pore network is favored in applications such as tissue engineering scaffolds. In this paper, foamed microcapillary films (FMCFs) are prepared based on a poly(lactic acid)/poly(butylene succinate) blend using melt extrusion and batch foaming with supercritical carbon dioxide. Such films are characterized by multiple hollow microcapillaries (diameter of 100-360 mu m) connected with cells (size of 3-194 mu m, open-cell content of over 80%) within the scaffold. By plugging the ends of the MCF before foaming, the formation of a solid skin layer is successfully avoided. Furthermore, the diameter of the microcapillaries of an FMCF can be adjusted using the designed foaming strategy. The effects of the foaming condition on the FMCF foaming behavior are also investigated. When other conditions are fixed, the foaming behavior changes dramatically when the foaming temperature changes within the range of 120-123 degrees C.