LAUSR

We report the preparation of a closed-cell polypropylene (PP) foam material by supercritical carbon dioxide foaming with the assistance of γ-ray radiation crosslinking. Styrene–ethylene–butadiene–styrene (SEBS) copolymer was added to PP to enhance radiation crosslinking and nucleation. Radiation effects on the foaming of the PP/SEBS blend with different ratios were investigated. A significant improvement in the foaming of the crosslinked PP/SEBS blend was achieved as compared to pristine PP. The cell density of the crosslinked PP/SEBS foam greatly increased at a dose of 10 kGy and a high closed-cell ratio was obtained. The tensile strength of the crosslinked PP/SEBS foams (10 kGy) was improved from 14 to 20.7 MPa compared to pristine PP foam (0 kGy). In addition, the crosslinked PP/SEBS blend exhibited a wider foaming temperature window (10 °C) as compared to the non-crosslinked ones (4 °C). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45809.