Curing Kinetics of Ultrahigh-Temperature Thermosetting Polyimides Based on Phenylethynyl-Terminated Imide Oligomers with Different Backbone Conformations

Minju Kim, Seongjun Khim, Joon Hyuk Lee, Eunkyung Jeon, Jungkun Song, Jaeho Choi, Hyeonuk Yeo, Ki Ho Nam

Research output: Contribution to journalArticlepeer-review

Abstract

A series of phenylethynyl-terminated imide (PETI) oligomers with varying chemical backbones and calculated number-average molecular weights were successfully synthesized via chemical imidization. These PETI oligomers exhibited exceptional solubility (>50 wt %) in both the high-boiling-point solvent N-methyl-2-pyrrolidinone (NMP) and low-boiling-point solvents tetrahydrofuran (THF) and 1,4-dioxane (dioxane). The curing reactivities of the PETI oligomers were assessed based on the dianhydride structure using a nonisothermal differential scanning calorimetry (DSC) method. Kinetic parameters, including the preexponential factor (A), activation energy (Ea), reaction order (n), and reaction rate constant (k), were determined using Kissinger, Ozawa, Crane, and Arrhenius equations. All PETI oligomers followed a first-order kinetic reaction model below 90% conversion. The curing process was characterized by two distinct stages: initiation and propagation. PETI oligomers containing electron-donating linkages (−O−) exhibited the lowest curing reactivity. In contrast, despite its slower initiation, the PETI oligomer containing electron-withdrawing groups (−CF3) exhibited the highest curing reactivity. Thermally cured resin derived from 2,3,3′,4′-biphenyltetracarboxylic dianhydride and 2,2′-bis(trifluoromethyl)benzidine is expected to exhibit excellent processability and thermal stability due to their high solubility, relatively low Tm (237.4-263.1 °C), and remarkable Td5% of 595.3 °C. This study provides a comprehensive understanding of the properties of PETI oligomers, enabling informed material selection for high-performance resin-based composite applications.

Original languageEnglish
Pages (from-to)13401-13412
Number of pages12
JournalACS Applied Polymer Materials
Volume6
Issue number21
DOIs
StatePublished - 8 Nov 2024

Keywords

  • curing kinetics
  • fiber-reinforced plastic
  • phenylethynyl-terminated imide
  • processability
  • structure parameters
  • thermal durability
  • thermosetting polyimides

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