Strategy for the preparation of lightweight polypropylene/polyethylene‐octene elastomer composite foams with different phase morphologies using supercritical carbon dioxide

Abstract

ABSTRACTPolypropylene (PP)/polyethylene‐octene elastomer (POE) composites with a “sea‐island” structure and a cocontinuous structure were prepared. With the selection of a suitable foaming temperature, the supercritical carbon dioxide foaming of PP/POE composites with different phase morphologies occurred only in the POE phase. The effects of the POE content, foaming temperature, pressure, and number of layers on the cell size, cell density, apparent density, foaming layer density, and foaming ratio under different phase morphologies were investigated by scanning electron microscopy, polarized optical microscopy, differential scanning calorimetry, and dynamic thermomechanical analysis. This article provides a novel approach for foaming PP at a low temperature. For PP/POE‐blended composites with a “sea‐island” structure, the foaming temperature is as low as 80 °C, and for PP/POE alternating multilayered composites with a cocontinuous structure, foaming can occur at 40 °C. Compared with the conventional methods for foaming PP, this method avoids the problems of a high foaming temperature, a narrow range of the foaming temperature, and a low melt strength of the PP. Thus, the PP foaming method was successfully improved, yielding a new technique for the preparation of lightweight PP. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48157.