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Effects of processing parameters and thermal history on microcellular foaming behaviors of PEEK using supercritical CO 2
Author(s) -
Yang Quan,
Zhang Guangcheng,
Ma Zhonglei,
Li Jiantong,
Fan Xiaolong
Publication year - 2015
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.42576
Subject(s) - peek , materials science , supercritical fluid , crystallinity , crystallization , blowing agent , composite material , foaming agent , chemical engineering , polymer , porosity , polyurethane , thermodynamics , physics , engineering
In this study, we mainly investigate the solid‐state foaming of polyether ether ketone (PEEK) with different crystallinities using supercritical CO 2 as a physical blowing agent. The gaseous mass‐transfer and thermophysical behaviors were studied. By altering the parameters of the foaming process, microcellular foams with different cell morphologies were prepared. The effect of crystallization on the cell morphology was also investigated in detail. The results indicate that the crystallization restricts gas diffusion in the material, and the thermophysical behaviors of the saturated PEEK sample with low crystallinity presents two cold crystallization peaks. The cell density decreases and the cell size increases as the saturation pressure increases. The cell density of the microcellular foams prepared under 20 MPa is 1.23 × 10 10 cells/cm 3 , which is almost 10 times compares to that under 8 MPa. The cell size increases as the foaming time extends or the foaming temperature increases. It is interesting that the cell morphology with a bimodal cell‐size distribution is generated when the samples are foamed at temperatures higher than 320°C for a sufficient time. Additionally, nanocellular foams can be obtained from a highly crystallized PEEK after the decrystallization process. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42576.