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Extrusion foaming of thermoplastic cellulose acetate sheets with HFO‐1234ze and co‐blowing agents
Author(s) -
Hendriks Sven,
Hopmann Christian,
Zepnik Stefan
Publication year - 2018
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.24850
Subject(s) - blowing agent , extrusion , materials science , foaming agent , methyl cellulose , composite material , cellulose , cellulose acetate , thermoplastic , viscosity , chemical engineering , polyurethane , porosity , engineering
Cellulose acetate is a bio‐based plastic which can be used to produce foam sheets through the extrusion process. In this study, different co‐blowing agents (BAs) were added to the foaming process in order to improve the extrusion foaming behavior and cell density of sheets foamed with HFO‐1234ze. The effect of co‐BAs on the melt viscosity was investigated with an inline extrusion rheometer. Furthermore, the resulting cell morphology of foam sheets was studied. While the plasticizing effect of the co‐BA is similar to HFO‐1234ze, the cell density of the foam sheets could be improved by adding co‐BAs in concentrations between 0.04 and 0.16 mol/kg. Adding 0.06 mol/kg of ethanol increased the cell density from approximately 1 to 12 × 10 5 1/cm³ at an invariant density of ∼130 kg/m³. The density reduction of the foam sheets can be calculated in good agreement from the molar concentration of the BAs. However, high amounts of co‐BA slightly reduce the BA yield. POLYM. ENG. SCI., 58:E182–E188, 2018. © 2018 Society of Plastics Engineers