CO2 nano-foaming of nanostructured PMMA

Abstract PMMA-based nano-cellular materials were produced using a gaseous CO 2 foaming process. PMMA has been investigated because of its CO 2 -philic behaviour, which allows high CO 2 uptake during the foaming process and facilitates the nucleation phenomenon. Nevertheless, one way to further increase the nucleation rate during the foaming process is to create a heterogeneous nucleation inside a polymer/nucleating agents system, while controlling the foaming process parameters. The addition of acrylate-based copolymers as potential nucleating agents to PMMA is the method chosen here to increase the nucleation rate. This study focuses on the foaming of blends of PMMA and acrylate-based copolymers with a batch process using gaseous CO 2 and presents the influence of the initial microstructure of the blends on their final foam structures. Under certain conditions, nano-cellular materials with an average cell size lower than 100 nm were obtained, a hundred times lower compared with PMMA foam.