Heating Effects on Structural and Electrical Properties of Polyetherimide

This work presents a detailed study, by thermostimulated depolarization currents, of the molecular mobility of poly (ether imide) in a broad temperature range covering the amorphous solid state, the glass transition, and the rubber state. Taking advantage of the very wide distribution of motional modes of the PEI glass transition (the broadest of all known glass formers), we carried out an in-depth study of physical aging involving different modes, which provided a more comprehensive view of the aging process. We also analyzed in detail the mobility below T g where, in addition to the fast secondary relaxation, we identified a Johari-Goldstein. In the rubber state, on the other hand, we detected a mobility but showed that it corresponds to space charge motions rather to dipolar reorientations.

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Low Dielectric Constant and Anisotropic Mechanical Properties of Dispenser‐Printed Polyetherimide Films Using Two‐Step Thermal Treatment

Kim

Hwang

Chung

et al. 2022

Macro Materials & Eng

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Although polyetherimide (PEI) has attracted attention owing to its good dielectric properties, superior mechanical properties, and thermal/chemical stabilities, there is still a lack of methodology to fabricate PEI films in desired shapes directly on devices. In this study, a dispenser printing method to fabricate sophisticated 2D PEI structures is introduced. As dispenser printing is a solution-based process, PEI ink is prepared by dissolving PEI in N-methyl pyrrolidone (NMP). The printing conditions are controlled by optimizing the pneumatic pressure and viscosity of the inks with various ratios of PEI and NMP, followed by a two-step heat treatment to develop fine PEI films. The dielectric constant of the PEI film increases from 2.28 to 2.61 with the corresponding secondary heating time of 1-5 h, which is much lower than the theoretical value owing to the free volume and loosely entangled polymer chains generated from the shear forces in printing and solvent evaporation. Furthermore, the film exhibits anisotropic mechanical properties in different printing directions, stemming from the alignment effect of the polymer molecules. It is believed that the developed PEI films and the facile methodology can be diversely tuned to provide new insights into material utilization, further extending the application fields.

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Heating Effects on Structural and Electrical Properties of Polyetherimide

Cited by 12 publications

References 20 publications

Polyetherimide

Polyetherimide

Dielectric relaxation study of poly (ether imide) by thermally stimulated depolarization currents

Low Dielectric Constant and Anisotropic Mechanical Properties of Dispenser‐Printed Polyetherimide Films Using Two‐Step Thermal Treatment

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