Effect of Molecular Weight on the Surface Tension of Polystyrene Melt in Supercritical Nitrogen
Bibliographic record
Abstract
This paper presents experimental results on the effect of molecular weight on the surface tension of polystyrene melt in supercritical nitrogen. The surface tension was determined by the axisymmetric drop shape analysis-profile (ADSA-P) method, for which a high-pressure and high-temperature cell was used to form pendant drops of the polystyrene melt. For two monodisperse polystyrenes of M w ∼ 100 000 and 400 000 and one polydisperse polystyrene, a linear relationship was found between surface tension and temperature and between surface tension and pressure within a temperature range of 170−210 °C and a pressure range of 500−2000 psi. With an increase in pressure or temperature, the surface tension of all three polystyrenes decreases. Monodisperse polystyrene of a higher molecular weight has a higher surface tension by 6−9 mJ/m 2 under all experimental conditions. The surface tension dependence on temperature and on pressure is more significant for the higher molecular weight polystyrene. For the polydisperse polystyrene, high surface tension values seem to be related predominantly to its high molecular weight portion of polystyrene molecules. An empirical equation, the Mecleod relation, was used to relate surface tension with the density difference between the polymer and supercritical nitrogen satisfactorily.
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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 | 0.004 | 0.001 |
| 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 | 0.001 |
| 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".