Influence of Structure on Chemical and Thermal Stability of Aliphatic Diesters
Bibliographic record
Abstract
Ester group interactions with each other and with the atoms between them were investigated in order to determine dependence of chemical and thermal stabilities of aliphatic diesters on structure. Novel glycol-derived diesters with chemical formula (C17H33COO)2C(n)H(2n) were used as model systems. Chemical stability was determined using (1)H NMR and FTIR, and thermal stability and weight-loss kinetics were examined using nonisothermal TGA. Chemical stability increased with the number of methylene units (n, carbon) between the ester groups until n = 6, and no significant improvement was observed past n > 6. It is argued that other ester-dense materials, including polyesters, would behave similarly. Evidence of a strong dependence of thermal stability on chemical stability is also provided. This work shows that the chemical and thermal stabilities of ester-dense functional materials such as diesters, oligo-esters, and polyesters can be manipulated by varying the distance between the ester groups, and hence the interactions of the electron-withdrawing ester groups with its neighbors.
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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".