Nanocomposites foams of poly(ethylene-co-vinyl acetate) with short and long nanocellulose fibers and foaming with supercritical CO₂

Nanotechnology applied to polymer foams is an emerging field, because even at low filler contents, different cellular morphologies can be obtained in the development of foams. Based on these premises, this work addresses the development of poly(ethylene-co-vinyl acetate)—EVA foams reinforced with two types of nanocellulose (a) short fibers (NC), and (b) long fibers (NCF). The foams were expanded in an autoclave with supercritical carbon dioxide (CO₂). Different expansion conditions were evaluated, with variations of temperature and pressure. The main results indicate that the presence of the fibers significantly reduces the size of the cells and increase the number of cells per unit area. However, by increasing the NC content, nanocellulose fibers agglomeration is observed, resulting in the formation of a bimodal cellular structure.