Hydroxyethylresorcinol- and hydroxyethylhydroquinone-containing poly(ethylene terephthalate) copolymers

Ryan J. Mondschein, Jon Hostetler, Clay B. Arrington, Timothy E. Long

Research output: Contribution to journalArticlepeer-review

Abstract

Melt polycondensation incorporating meta-substituted hydroxyethylresorcinol (HER) or para-substituted hydroxyethylhydroquinone (HEH) regioisomers enabled the synthesis of poly(ethylene terephthalate) (PET)-based (co)polyesters with targeted comonomer mol %. Incorporation of either HER or HEH lowered the glass transition temperature (Tg) relative to PET, but the 5% weight loss temperature (Td,5%) remained unchanged. Similarly, the semi-crystalline morphology varied as a function of comonomer selection and mol % comonomer. Dynamic mechanical analysis confirmed decreasing β-relaxation intensities upon HER and HEH incorporation, while HER impacted β-relaxation intensity more substantially at similar mol %. HER incorporation also shifted the β-relaxation temperature (Tβ) to lower temperatures considerably more than HEH. Time-temperature-superposition (TTS) and Williams-Landel-Ferry (WLF) analysis of melt rheology probed various physical polymer properties including melt flow activation energy (Ea), fractional free volume at Tg (fg), and molecular weight of entanglement (Me). HER-based (co)polyesters exhibited lower Ea compared to HEH. Likewise, HER incorporation lowered fg while HEH incorporation increased fg. HER-based (co)polyesters possessed a higher Me compared to HEH-based (co)polyesters, although both copolymers resulted in higher Me compared to PET. Tensile testing revealed HER/HEH-based (co)polyesters ultimate mechanical performance compared to amorphous PET. Both HER and HEH incorporation increased Young's moduli and yield strengths, although comonomer incorporation above 25–30 mol % yielded minimal change. Establishing structure-property relationships provided insight into the role of regioisomeric variation at various comonomer levels on thermal, rheological, and mechanical performance for PET-based copolymers.

Original languageEnglish (US)
Article number123890
JournalPolymer
Volume228
DOIs
StatePublished - Jul 16 2021
Externally publishedYes

Keywords

  • HER
  • Hydroxyethylhydroquinone
  • Hydroxyethylresorcinol
  • PET
  • Polyester

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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