Influence of Branch Side-Chains on the Foaming Properties of Thermoplastic Polyether Ester Elastomers in Supercritical CO2

Abstract

Ester-based polymers are widely used in numerous applications today. However, thermoplastic polyether ester elastomer (TPEE), despite being an ester-based elastomer, is typically unsuitable for lightweight applications due to its limited foamability, caused by low melt strength and a narrow molecular weight distribution. This study performed a series of TPEE modifications using a methyl-branched diol (neopentyl glycol) as the monomer and a tri-block polymer (ENHOL BE-3520) as the soft segment. Adjustments to the methyl-branched diol content notably impacted the thermal properties of the TPEE. All modified samples demonstrated decomposition temperatures exceeding 300°C at 5% weight loss, and melting temperatures ranging from 159°C to 219°C. Tensile strengths varied between 14.66 and 22.96 MPa, while the foam samples achieved expansion rates of 1.50% to 2.45% at temperatures 5°C below the melting point, and 2.19% to 3.88% at 10°C below the melting point. These modifications resulted in TPEE foams with enhanced mechanical properties and stable structures, significantly expanding their potential applications.