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Extrusion of poly(ether imide) foams using pressurized CO 2 : Effects of imposition of supercritical conditions and nanosilica modifiers
Author(s) -
Aktas Seda,
Gevgilili Halil,
Kucuk Ilknur,
Sunol Aydin,
Kalyon Dilhan M.
Publication year - 2014
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.23753
Subject(s) - materials science , blowing agent , supercritical fluid , composite material , extrusion , porosity , plastics extrusion , nucleation , foaming agent , viscoelasticity , polyurethane , thermodynamics , physics
Foams of an engineering plastic, poly(ether imide), were extruded using a single screw extruder employing pressurized CO 2 as the blowing agent. The porosity, pore size distributions, and the density of the foams were especially affected by the pressure drop, the pressure loss rate, and temperature at the die. Significant increases in porosity and pore size and corresponding decreases in density were observed when the pressure imposed on CO 2 became greater than the critical pressure values of CO 2 (i.e., the temperature was always greater than the critical temperature of the CO 2 in the extruder and the die). The viscoelastic material functions of the extruded foams depended especially on the density of the foam, with the elastic modulus increasing with density. The incorporation of nanosilica particles in the 0.08–0.6% by weight range increased only the density of the foam and did not provide any benefits in controlling of the nucleation rate and the pore size distribution, presumably due to their poor dispersibility and agglomerated state in the single screw extruder. POLYM. ENG. SCI., 54:2064–2074, 2014. © 2013 Society of Plastics Engineers