Physical ageing studies in polyetherimide ULTEM 1000

Belana, J.; Cañadas, J. C.; Diego, J. M.; Mudarra, M.; Dı́az, Raúl; Friederichs, S.; Jaime's, Catherine; Sanchı́s, M. J.

doi:10.1002/(sici)1097-0126(199805)46:1<29::aid-pi947>3.0.co;2-c

Cited by 36 publications

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“…To verify the assumption of increased free volume in the PDZ, and whether changes to the molecular weight also affect the local strength in the PTMAZ, a replicate of the high-energy-input joint from Figure 9 was subsequently annealed for 24 h at 200 • C (Tg-15 • C). The time and temperature of annealing were based on the maximized physical aging of PEI as reported by Belana et al [43]. Annealing of amorphous polymers promotes accelerated physical aging.…”

Section: Physical-chemical Changes In the Microstructural Zones Of F-mentioning

confidence: 99%

Process-Related Changes in Polyetherimide Joined by Friction-Based Injection Clinching Joining (F-ICJ)

et al. 2020

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This work presents a comprehensive study on the effects of the Friction-based Injection Clinching Joining (F-ICJ) process on the microstructure and local properties of the stake head. The manuscript evaluates the consequences on the quasi-static mechanical performance of hybrid joints of amorphous polyetherimide (PEI) with aluminium AA6082. Through an overlay of microhardness map on a cross-polarized transmitted-light optical microscopy (CP-TLOM) image, two lower-strength microstructural zones in the PEI stake head were observed: a plastically-deformed zone (PDZ) and a thermo-mechanically-affected zone (PTMAZ). When compared to the base material, PDZ and PTMAZ have a reduction of 12%–16% and 8%–12%, respectively, in local mechanical properties. The reduced local strength was associated with distinct volumes of loosely packed PEI chains with unsteady chain conformation and thus larger free volume in the affected regions. The mechanical strength reduction is reversible through physical aging by thermal annealing the joints, which additionally shows that process-induced thermomechanical degradation of PEI by chain scission, as evidenced by size exclusion chromatography (SEC) analysis, does not appear to affect local mechanical strength. An evaluation of typical loading regimes of staked joints in lap shear (average ultimate force of 1419 ± 43 N) and cross tensile (average ultimate force of 430 ± 44 N) testing indicates that the process-induced changes of PEI do not compromise the global mechanical performance of such a structure. These findings provide a better understanding of the relationships between processing, microstructure, and properties for further F-ICJ process optimization.

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Section: Physical-chemical Changes In the Microstructural Zones Of F-mentioning

confidence: 99%

Process-Related Changes in Polyetherimide Joined by Friction-Based Injection Clinching Joining (F-ICJ)

et al. 2020

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“…4 the inset illustrates the cross-over region and the α-relaxation to indicate differences in the expressions used in the data analysis. No care was given here to separate α and β relaxations as in previous studies [10,[52][53][54][55][56].…”

Section: Relaxation Mapmentioning

confidence: 99%

Electrical properties of polyetherimide thin films: Non-parametric dielectric response analysis with distribution of relaxation times

Tuncer

2017

Eur. Phys. J. E

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High temperature polymeric materials for electrical insulation and energy storage are needed for transformational power applications such as pulsed-power and hybrid electrical vehicles. One of the candidate materials has been polyetherimide, an amorphous thermoplastic with a glass transition over 200 C. Here, the dielectric studies on the material are reported by taking into account the polarization and conduction processes in the polyetherimide. The dielectric data were analyzed with the distribution of relaxation times approach with Debye expression as the kernel in the inversion algorithm, the results then created the relaxation map for polyetherimide. The method satisfies the Kramers-Kronig relationships, so the ohmic conductivity and permittivity at high frequencies could be estimated from the experimental data even if there exists significant measurement error. The data were compared to the published results on polyetherimide in the literature. The materials is a low loss polymer with negligible ohmic losses below 200C. The estimated fragility of the polyetherimide was high about 284 from the resolved relaxation map using the Vogel-Fulcher-Tammann-Hesse expression. Polyetherimide is a good dielectric for advanced energy storage and electrical insulation technologies up to 200 C.

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“…Scanning Calorimetry (DSC) is used to investigate the thermal transitions in the polymer, for instance, it allows to determine the glass transition temperature. Moreover, the enthalpy relaxation due to physical ageing can be determined from DSC measurements [8] .…”

Section: Differential Scanning Calorimetry: Differentialmentioning

confidence: 99%

“…Studies on the effects of these parameters could give information on material reliability. Numerous investigations on PEI properties have been made by researchers [1][2][3][4][5][6][7][8][9] . The relaxational behaviour of this material is one of the researched topics.…”

Section: Introductionmentioning

confidence: 99%

Heating Effects on Structural and Electrical Properties of Polyetherimide

Guermazi¹

2009

American J. of Engineering and Applied Sciences

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Problem statement: Polyetherimide (PEI) has several uses such as electrical insulation. It can undergo different constraints like heat or high voltage which influence its performances as insulator. In this study, the effects of heating on structural and electrical properties of polyetherimide (Ultem 1000) are studied. Approach: PEI samples were heated at different temperatures below the glass transition temperature (175, 190 and 205°C). Different complementary techniques were used to investigate structural alterations and dielectric relaxations. These are infrared (IR) spectroscopy, Differential Scanning Calorimetry (DSC), Thermally Stimulated Depolarisation Current (TSDC) technique and Dielectric Spectroscopy (DS). Results: Physical ageing was revealed in heated samples by DSC analysis. DS and TSDC results have shown that dipolar relaxations are affected by heating. The amount of relaxing dipoles decreases when the material is heated at 190°C. Conclusion/Recommendations: The heating of polyetherimide at 190°C leads to a stabilisation of charges in deeper energetic levels which influences the insulating character of the material.

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Physical ageing studies in polyetherimide ULTEM 1000

Cited by 36 publications

References 0 publications

Process-Related Changes in Polyetherimide Joined by Friction-Based Injection Clinching Joining (F-ICJ)

Process-Related Changes in Polyetherimide Joined by Friction-Based Injection Clinching Joining (F-ICJ)

Electrical properties of polyetherimide thin films: Non-parametric dielectric response analysis with distribution of relaxation times

Heating Effects on Structural and Electrical Properties of Polyetherimide

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