Sustainable polymer foaming using high pressure carbon dioxide: a review on fundamentals, processes and applications

Abstract

In recent years, carbon dioxide (CO 2 ) has proven to be an environmentally friendly foaming agent for the production of polymeric foams. Until now, extrusion is used to scale-up the CO 2 -based foaming process. Once the production of large foamed blocks is also possible using the CO 2 -based foaming process, it has the potential to completely replace the currently used foam production process, thus making the world-wide foam production more sustainable. This review focuses on the polymer-CO 2 -foaming process, by first addressing the principles of the process, followed by an overview of papers on nucleation and cell growth of CO 2 in polymers. The last part will focus on application of the process for various purposes, including bulk polymer foaming, the production of bioscaffolds and polymer blends.

Nanoporous polymeric materials: A new class of materials with enhanced properties

“…This gas is one of the best options for this type of process because of its excellent diffusion characteristics in the supercritical state and the relatively mild conditions to reach this state (31°C and 7.3 MPa). Furthermore, carbon dioxide is a green solvent that can be removed without residue or the production of any pollutant compound [40,41].…”

Structural properties of batch foamed acrylonitrile butadiene styrene/nanoclay nanocomposites

“…Microcellular foams are defined as foams with a cell diameter lower than 10 μm and cell density more than 10 10 cells/ cm 3 (Jacobs et al 2008). The cell radius of microcellular foams is less than the natural critical crack of a polymer; therefore, polymer weight can be reduced without having a negative effect on mechanical properties compared to traditional foams.…”

Biodegradable polylactide/hydroxyapatite nanocomposite foam scaffolds for bone tissue engineering applications

“…However, these approaches typically involve organic solvents, which is a problem for implementation [25], providing a strong driving force for the development of solvent-free processing techniques [11][12][13][14]26], such as supercritical fluid foaming [27,28]. In supercritical fluid foaming, pressure and temperature control is determinant for the growth and stabilization of a cellular morphology and hence the final properties of the material, which may also vary with filler content, crystallinity, and fluid content [27,29].…”