Characterization of polylactic acid-based nanocomposite foams with supercritical CO2

[Display omitted] •Poly(lactic acid) matrix nanocomposite foams were prepared with the aid of sc-CO2.•MMT and halloysite nanotubes significantly increased cell nucleating capability.•Excellent dispersion of halloysite nanotubes was achieved.•Both halloysite and CNT increased the specific compressive strength of the foams. In this research, we physically foamed semicrystalline polylactic acid filled with montmorillonite, carbon nanotubes, and halloysite nanoparticles. In the case of polymer foams, their density and compressive strength are important parameters. Although the specific compressive strength calculated as the ratio of the two is a good indicator of the use of polymeric foams, few researchers use this ratio for classification. We have shown that the presence of nanoparticles has a positive effect on this parameter, especially with the use of 3 wt% halloysite, when this value increased from 12.07 ± 7.5 [MPa/(g/cm3)] to 20.89 ± 1.75 [MPa/(g/cm3)], i.e., by more than 70%. In general, the presence of nanoparticles reduced the standard deviation of this ratio. Regardless of the nanoparticles used, the average cell diameter decreased compared to that of the reference material. The results were explained with the cell nucleating ability of halloysite.