Applications and Challenges of Supercritical Foaming Technology

Abstract

With economic development, environmental problems are becoming more and more prominent, and achieving green chemistry is an urgent task nowadays, which creates an opportunity for the development of supercritical foaming technology. The foaming agents used in supercritical foaming technology are usually supercritical carbon dioxide (ScCO2) and supercritical nitrogen (ScN2), both of which are used without environmental burden. This technology can reduce the environmental impact of polymer foam production. Although supercritical foaming technology is already in production in some fields, it has not been applied on a large scale. Here, we present a detailed analysis of the types of foaming agents currently used in supercritical foaming technology and their applications in various fields, summarizing the technological improvements that have been made to the technology. However, we have found that today’s supercritical technologies still need to address some additional challenges to achieve large-scale production.

Polystyrene carbon composite foam with enhanced insulation and fire retardancy for a sustainable future: Critical review

“…Using supercritical CO 2 blowing agent to produce lightweight microcellular foams is not only environment friendly but can offer a better control in cell nucleation by controlling the process parameters. 81,183,184 In this regard, more research needs to be conducted on the use of supercritical CO 2 to study the exfoliation of the carbon in the polymer matrix. We believe that elucidating the study of compatibility of carbon and polymer matrix could help in understanding its effect on morphology, cell formation and insulation performance.…”

MXenes and Clay Minerals in the Framework of the 2D Organic–Inorganic Hybrid Nanomaterials

“…169 Foams can be also advantageously produced by application of supercritical CO 2 or N 2 technologies which reduce the impact of environmental pollution with respect to alternative methods. 170 XRD patterns indicate that the combination of clays with biopolymers can result in bionanocomposites showing a regular structural organization. This is for example the case of bionanocomposites resulting from the intercalation of chitosan in montmorillonite and other 2D clays 167,171 by relatively regular intercalation with well-defined interlayer separation.…”

“…Procedures of foaming based on the two-step quenching route has been useful for the conformation of biodegradable polymers . Foams can be also advantageously produced by application of supercritical CO 2 or N 2 technologies which reduce the impact of environmental pollution with respect to alternative methods …”

Thermodynamics of the Glassy Polymer State: Equilibrium and Non-Equilibrium Aspects

“…As mentioned above, in terms of mechanical strength, the glass transition is associated with a drop of three orders of magnitude in the elasticity modulus with the change from the relatively strong glassy polymer state to the elastic rubber state. Thus, T g is important for practical applications of the polymer, as well as for its modification into advanced materials, such as microcellular foams or microporous scaffolds for tissue-engineering applications [ 8 , 9 , 10 , 11 ]. In foaming applications, supercritical fluids at moderately high pressures are extensively used as foaming agents.…”