Polymer ferroelectret based on polypropylene foam: Piezoelectric properties improvement using post‐processing thermomechanical treatment
Bibliographic record
Abstract
ABSTRACT In this work, the effect of post‐processing parameters (time, temperature, and pressure) on the morphology as well as mechanical and piezoelectric properties of foamed polypropylene (PP) films were studied. Two different post‐processing methods, based on the saturation of a foamed film with supercritical nitrogen (N 2 ), were used to obtain an optimized eye‐like cellular structure with a high cell aspect ratio ( AR ). The results showed that, when the PP‐foamed films were exposed to a gradual temperature and pressure increase, an appropriate cellular structure with high AR value (about 6.6) was obtained. This structure led to a high quasi‐static piezoelectric d 33 coefficient of 800 pC/N (45% higher than for untreated ones) indicating the importance of the post‐processing treatment on the piezoelectric behavior of these films. On the other hand, when the treatment was performed in steps, cell morphology changed from an eye‐like to a less elongated shape, resulting in lower d 33 values. The tensile characterization showed that higher cell aspect ratio led to lower Young's modulus, which is suitable to achieve higher piezoelectric properties. Finally, dynamic mechanical analysis (DMA) was used as a simple method to correlate mechanical and piezoelectric properties of cellular PP. This was done via the ratio of the storage moduli in the longitudinal and transverse directions, which is directly related to film anisotropy ( AR value) and thus to the piezoelectric behavior. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44577.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".