Abstract
Polystyrene (PS) foams are fabricated using supercritical carbon dioxide (Sc-CO2) as a physical foaming agent in a batch foaming process. It is demonstrated that a bi-modal cell structure (BMCS) is obtained by the synergistic effect of temperature rising and depressurization using a varying-temperature mode (VTM). The formation mechanism for the BMCS is revealed. Cell nucleation occurs in the supercritical CO2-saturated polymer both in temperature rising and depressurizing stages. The nuclei formed in the former stage develop into large cells, whereas the ones formed in the latter stage evolve into small cells. The effects of foaming temperature, saturation temperature, second saturation time and foaming pressure in the VTM on the cellular structure of PS foams were investigated. The results showed that no BMCS is formed when the foaming temperature is only 10°C higher than saturation temperature. By manipulating the foaming parameters, the BMCS PS foams with a wide range of mean diameters (50.0–713.7μm) and densities (2.1×103–3.6×106cells/cm3) for the large cells, and a wide range of foam density (0.09–0.73g/cm3) are obtained.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
