Opening Pores and Extending the Application Window: Open‐Cell Nanocellular Foams

Abstract

AbstractThe production of open‐cell (OC) nanostructures in polymer foams without non‐foamed solid skins by gas dissolution foaming has been developed in this work. First, several grades of MAM block copolymer (methyl methacrylate‐b‐butyl acrylate‐b‐methyl methacrylate) at high content are employed as heterogeneous phase in poly(methyl methacrylate) for producing OC structures. Atomic force microscopy and extensional rheology are used as methods to understand the main features to obtain OC nanocellular structures. Second, the gas diffusion barrier approach is employed for the first time in polymer blends to avoid the appearance of the solid skins in the borders, which typically appears when the cellular polymer is produced by gas dissolution foaming. The influence of the poly(vinyl alcohol) gas diffusion barrier is analyzed, together with the effect of heterogeneous nucleation provided by MAM copolymer, on the solid skins’ formation. The synergy between both approaches allows obtaining porous nanocellular polymeric films with an OC structure non‐constrained by the presence of outer solid skins.