Thermodynamics and Kinetic Processes of Polymer Blends and Block Copolymers in the Presence of Pressurized Carbon Dioxide

Abstract

Environmentally‐responsible materials processing is becoming an important global consideration in a wide variety of technologies, especially those wherein volatile and/or residual organic solvents cannot be tolerated. In this context, polymer processing has benefited tremendously from advances achieved using high‐pressure CO2 as a viscosity modifier, plasticizing agent, foaming agent, and reaction medium. Pressurized CO2 is environmentally benign, inexpensive, sustainable, and versatile owing to its gas‐like viscosity and liquid‐like solubility, which can be tuned through judicious choice of temperature and pressure. The addition of high‐pressure CO2 to homopolymer blends and block copolymers can have a profound impact on polymer thermodynamics and kinetic processes since the number of interacting species increases. As a result, the compressibility as well as plasticization and intermolecular screening effects become non‐negligible. In this work, we review how these factors influence such polymeric systems, and discuss commercial polymer processes and applications that benefit from the use of high‐pressure CO2.

Polymer nano-foams for insulating applications prepared from CO2 foaming

“…The latter is the slower one and therefore the more kinetically determining. These phenomena have been widely investigated for polymer/CO 2 systems because of the significant development of polymer blending and processing withpressurized CO 2 [32].…”

Swelling measurement of polymers in high pressure carbon dioxide using a spectroscopic reflectometer

“…For processes involving polymers, CO 2 has been used as a plasticizer [3][4][5], a micro-or nano-foaming agent [6][7][8], a compatibilizer of polymer blends [9], and an additive to tune block copolymer morphologies [10][11][12][13][14]. Most polymers do not dissolve, but rather swell in CO 2 depending on the temperature and pressure.…”

New challenges in polymer foaming: A review of extrusion processes assisted by supercritical carbon dioxide

“…In an extrusion process, sc-CO 2 will change the rheological properties of the material inside the extruder and will play the role of an expansion agent [22][23][24]. The diminution of viscosity will result in the limitation of mechanical Fig.…”