Investigation of the accelerated thermal aging behavior of polyetherimide and lifetime prediction at elevated temperature
Bibliographic record
Abstract
Abstract Fire‐protective clothing are manufactured using heat and flame resistant fibers that are made of high‐performance polymers. These polymers exhibit a gradual reduction in their performance after long‐term exposure under various aging conditions. This study investigates the thermal aging behavior of a high‐temperature resistance polymer, polyetherimide (PEI), at elevated temperatures in air. Changes in the ultimate tensile strength (UTS), glass transition temperature, and surface properties are observed. In addition, infrared spectroscopy identifies chemical bonds in PEI being consumed because of chain scission. Applying the time–temperature superposition principle to the UTS data gives an activation energy of 112 kJ mol −1 for the effect of thermal aging on the mechanical strength of PEI. This value is similar to what has been reported for fire‐protective clothing fabrics, which opens the possibility to use PEI as a sensing material for the development of end‐of‐life sensors for fire‐protective fabrics.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".