Role of chain extension in the rheological properties, crystallization behaviors, and microcellular foaming performances of poly (butylene adipate‐co‐terephthalate)

Abstract

ABSTRACT Currently, the fabrication of microcellular semicrystalline polymer foam using supercritical CO 2 as a blowing agent constitutes a worldwide interest. In this work, a facile approach of chain extension and batch foaming was proposed to prepare microcellular semicrystalline poly (butylene adipate‐co‐terephthalate) (PBAT) foam using CO 2 as a physical blowing agent. With the introduction of chain extender (CE), the weight‐average molecular weight and gel fraction of PBAT samples increased; their crystallization temperature increased from 74.2 to 86.9 °C and their viscoelasticity was improved greatly. Microcellular PBAT foams with the cell size <4 μm and the cell density more than 10 10 cells cm −3 were fabricated successfully. With increasing concentration of CE, the cell density and volume expansion ratio (VER) of various PBAT foams increased from 3.4 × 10 10 to 8.7 × 10 10 cells cm −3 and from 1.5 to 2.0 times, respectively. With increasing foaming temperature, the cell size and VER increased and the cell density decreased. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47322.