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Investigation of the nanocellular foaming of polystyrene in supercritical CO 2 by adding a CO 2 ‐philic perfluorinated block copolymer
Author(s) -
Ruiz Jose Antonio Reglero,
Cloutet Eric,
Dumon Michel
Publication year - 2012
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.36455
Subject(s) - copolymer , polystyrene , materials science , supercritical fluid , extrusion , polymer , chemical engineering , polymer chemistry , polymerization , blowing agent , composite material , chemistry , organic chemistry , polyurethane , engineering
Nanocellular foaming of polystyrene (PS) and a polystyrene copolymer (PS‐ b‐ PFDA) with fluorinated block (1,1,2,2‐tetrahydroperfluorodecyl acrylate block, PFDA) was studied in supercritical CO 2 (scCO 2 ) via a one‐step foaming batch process. Atom Transfer Radical Polymerization (ATRP) was used to synthesize all the polymers. Neat PS and PS‐ b‐ PFDA copolymer samples were produced by extrusion and solid thick plaques were shaped in a hot‐press, and then subsequently foamed in a single‐step foaming process using scCO 2 to analyze the effect of the addition of the fluorinated block copolymer in the foaming behaviour of neat PS. Samples were saturated under high pressures of CO 2 (30 MPa) at low temperatures (e.g., 0°C) followed by a depressurization at a rate of 5 MPa/min. Foamed materials of neat PS and PS‐ b‐ PFDA copolymer were produced in the same conditions showing that the presence of high CO 2 ‐philic perfluoro blocks, in the form of submicrometric separated domains in the PS matrix, acts as nucleating agents during the foaming process. The preponderance of the fluorinated blocks in the foaming behavior is evidenced, leading to PS‐ b‐ PFDA nanocellular foams with cell sizes in the order of 100 nm, and bulk densities about 0.7 g/cm 3 . The use of fluorinated blocks improve drastically the foam morphology, leading to ultramicro cellular and possibly nanocellular foams with a great homogeneity of the porous structure directly related to the dispersion of highly CO 2 ‐philic fluorinated blocks in the PS matrix. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012