Controlling the foam morphology of supercritical CO 2 ‐processed poly(methyl methacrylate) with CO 2 ‐philic hybrid nanoparticles

• Published in: Journal of applied polymer science Vol. 138; no. 33
• Main Authors: Ozkutlu, Merve, Bayram, Goknur, Dilek, Cerag
• Format: Journal Article
• Language: English
• Published: 05.09.2021
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.50814

Abstract Highly CO 2 ‐philic nanoparticles, octatrimethylsiloxy polyhedral oligomeric silsesquioxanes (POSS) are used to increase the affinity of poly(methyl methacrylate) (PMMA) to CO 2 in supercritical carbon dioxide (scCO 2 ) foaming, thus to improve its foaming performance and the foam morphology. PMMA and PMMA‐POSS composite foams were produced based on the two‐factorial design, at the upper and lower experimental conditions of pressure, temperature, processing time, and venting rate. The foams of PMMA‐5% POSS composites exhibited smaller average pore sizes and higher pore densities than neat PMMA and PMMA‐0.5% POSS composites. The smallest average pore diameter (0.3 μm) and the highest pore density (6.33 × 10 12  cm −3 ) were obtained with this composite processed at 35°C, 32 MPa, for 24 h and depressurized with fast‐venting rate (0.4 MPa/s). ScCO 2 processing decreased the density of the polymer by more than 50%.