Mechanical Properties and Thermal Degradation Kinetics of a Novel Thermally Stable Thermoplastic Poly(ester-ether) Elastomer Containing N′N-Bis(2-carboxymethyl) Pyromellitimide Unit

Abstract

A novel thermally stable thermoplastic poly(ester-ether) (PEE) elastomer containing imide units was prepared from poly(tetramethylene glycol) (PTMG1000), 1,4-butanediol (BD) and a new imide dicarboxylic acid based on pyromellitic dianhydride (PMDA) and glycine through a traditional chemical two-step method. The structures of the synthesized imide dicarboxylic acid and novel PEE were confirmed by FT-IR spectroscopy. The mechanical properties of the novel PEE were investigated. Thermal stability and thermal degradation kinetics of the novel PEE were investigated by thermogravimetric analysis (TGA) under different heating rates. The kinetic parameters of the degradation process were determined by using Kissinger, Flynn–Wall–Ozawa and Friedman methods. The Coats–Redfern method was also used to discuss the probable degradation mechanism of this PEE. The results showed that introduction of the imide units into the poly(ester-ether) endowed the PEE with excellent thermal stability and good mechanical properties. The activation energy obtained by using the Kissinger method was in agreement with that using the Flynn–Wall–Ozawa method. The reaction order (n) and pre-exponential factor (A) were obtained by using the Friedman method. Analysis of the experimental results suggests that the decomposition reaction mechanism of the PEE was a F₃ type (random nucleation with three nuclei on the individual particle).

Keywords:

• Poly(ester-ether)
• thermoplastic elastomers
• imide
• thermal stability
• degradation kinetics
• mechanical properties

Acknowledgments

The authors wish to express their gratitude to the Chinese National Nature Science Foundation (50973064) for financial support of this research.

Shaojian Lin and Jiaojiao Shang contributed equally to this work as co-first authors.

Contract grant sponsor: Chinese National Nature Science Foundation. Contract grant number: 50973064.