Regeneration of nanoporous crystalline syndiotactic polystyrene by supercritical CO2

✍ Scribed by Ernesto Reverchon; Gaetano Guerra; Vincenzo Venditto

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 130 KB
• Volume: 74
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19991121)74:8<2077::aid-app24>3.0.co;2-i

✦ Synopsis

Guest desorption procedures for s-PS clathrate samples, leading to formation and regeneration of the nanoporous ␦ phase, are compared. An extraction procedure, based on supercritical carbon dioxide, allows an easy and fast recovery of the guest molecules operating under relatively mild conditions (90 -200 bar, 40°C) and generates a completely empty ␦ form, also starting from the most stable s-PS clathrate forms. In agreement with a previously proposed crystal structure of the nanoporous ␦ form, X-ray diffraction patterns of ␦ form powders obtained by this procedure do not show the peak, which is reduced but still apparent in samples extracted with previous procedures based on boiling solvents.