Fabricationof Poly(lactic acid)/Graphene Oxide Foamswith Highly Oriented and Elongated Cell Structure via UnidirectionalFoaming Using Supercritical Carbon Dioxide.

Thesignificant influence of graphene oxide (GO) on the unidirectionalfoaming of poly(lactic acid) (PLA) using supercritical CO2as blowing agent was investigated in this study for the first time.Highly oriented and elongated cell structures were obtained from thePLA/GO nanocomposites foams. The thermal, rheological, and CO2absorption properties of the PLA/GO nanocomposites were studiedto investigate the effect of GO on PLA unidirectional foaming. Itwas found that the incorporation of GO improved the storage modulus,loss modulus, and complex viscosity of the PLA/GO nanocomposites significantly.The addition of GO improved the CO2absorption abilityof the nanocomposites, which caused high expansion ratio and increasedaverage cell size during foaming process. The high expansion forceby enhanced CO2absorption, high matrix viscosity of PLA/GOnanocomposites, and restriction of the mold in three directions togethercaused the formation of the highly elongated cell structure duringfoaming. [ABSTRACT FROM AUTHOR]