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Foam formation from fluorinated polyphosphazenes by liquid CO 2 processing
Author(s) -
Steely Lee B.,
Li Qixiu,
Badding John V.,
Allcock Harry R.
Publication year - 2008
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.20995
Subject(s) - materials science , polymer , solubility , solvent , scanning electron microscope , raman spectroscopy , swelling , chemical engineering , polymer chemistry , fire retardant , composite material , organic chemistry , chemistry , physics , optics , engineering
Three dimensional foams of fluorinated polyphosphazenes were prepared using liquid CO 2 to solvate polymer films, which were then expanded by volatilization of liquid CO 2 within the polymer matrix. The polymers dissolved in CO 2 at 1.5 × 10 7 Pa (2200 psi) and room temperature. Materials were examined using Raman spectroscopy before and during high pressure CO 2 exposure. The solubility in liquid CO 2 is attributed to interactions between the solvent and the fluorine atoms in the polymer side groups. Fluoroalkoxy polyphosphazenes are known for their hydrophobicity and fire retardant properties, and these characteristics are retained in the foams. Scanning electron microscopy, water swelling, and preliminary fire retardance tests were conducted to determine the morphology and properties of the foams. These materials are possible candidates for a number of different engineering applications. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers