Action of water in the degradation of low-density polyethylene studied by X-ray photoelectron spectroscopy
Bibliographic record
Abstract
Industrial low-density polyethylene (LDPE) was aged in stagnant distilled water during one year.Two types of this material were studied.The first one was without additives and the second type was doped with 4% of hindered-amine light stabilizers (HALS).Using X-ray photoelectron spectroscopy (XPS), the evidence that an oxidation occurs was demonstrated for the two types of LDPE (with and without HALS).One objective was to observe the chemical groups resulting of the ageing and to propose a mechanism of hydrolytic degradation for LDPE.The analysis of C1s spectra shows that the main oxidation products are C-O and C=O groups.Unlike the hydrolytic degradation of polypropylene, there is no presence of O=C-O groups, which suggests that there is no oxidative chain scission during hydrolytic ageing of the LDPE.The other objective of the study was to observe if the HALS can have an influence in the hydrolytic ageing of the LDPE.The values of the atomic concentration of the oxygen for the two types of samples show that the HALS could slightly slow down the oxidation of the LDPE.
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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".