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Polymeric materials formed by precipitation with a compressed fluid antisolvent
Author(s) -
Dixon David J.,
Johnston Keith P.,
Bodmeier Roland A.
Publication year - 1993
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690390113
Subject(s) - materials science , polystyrene , polymer , porosity , precipitation , chemical engineering , nozzle , jet (fluid) , phase (matter) , glass transition , composite material , chemistry , thermodynamics , organic chemistry , physics , meteorology , engineering
Abstract Polymer microspheres and fibers are formed with a versatile new process, precipitation with a compressed fluid antisolvent. By spraying a 1 wt. % polystyrene in toluene solution into CO 2 through a 100‐μm nozzle, microspheres are formed with diameters from 0.1 to 20 μm as the CO 2 density decreases from 0.86 to 0.13 g/cm 3 . The uniform submicron spheres produced at high CO 2 density are due in part to the rapid atomization produced by the large intertial and low interfacial forces. Fibers, with and without microporosity, are obtained at higher polymer concentrations where viscous forces stabilize the jet. The effect of CO 2 density and temperature on the size, morphology and porosity of the resulting polymeric materials is explained in terms of the phase behavior, spray characteristics, and the depression in the glass transition temperature.