Synthesis and Characterization of Aliphatic-Aromatic Copolyesters Based on Daidzein
Bibliographic record
Abstract
A novel diol monomer, 7-(2-hydroxyethoxy)-3-(4-(2-hydroxyethoxy)phenyl)-4H-chromen-4-one (M), was synthesized by hydroxyethylation of daidzein, a lignin-derived compound that can be extracted from leguminous plants. A diester monomer, dimethyl 4,4′-((1,4-phenylenebis(methylene))bis(oxy))bis(3-methoxybenzoate) (N), was obtained through a Williamson etherification reaction of methyl vanillate, potentially derived from plants such as Hovenia dulcis . The reaction of the two biobased monomers coupled with aliphatic diols (ethylene glycol, 1,4-butanediol, 1,6-hexanediol, or 1,8-octanediol) in a two-step melt polymerization process yielded a series of novel aliphatic-aromatic copolyesters. Structure–property relationships of these materials were established through Fourier transform infrared spectroscopy, NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis. The weight-average molecular weight ( M w ) of the samples ranged from 62,600 to 69,900 g/mol, and varying the carbon chain length in the aliphatic diol monomers not only induced changes in molecular weights but also synergistically tuned the thermal stability and mechanical properties of the copolymers. Thermal analysis yielded glass transition temperatures ( T g ) of 115–141 °C, melting temperatures ( T m ) of 271–308 °C, and 5% decomposition temperatures ( T d,5% ) of 397–460 °C. The mechanical analysis exhibited high yield strength (50–115 MPa) and elongation at break (235–300%) values. After 32 weeks of degradation in soil, the copolyesters experienced mass losses of up to 4.1%. Ecotoxicity studies showed that the 14-day survival rate of earthworms exposed to the copolyesters was above 80%, suggesting a low toxicity in the environment. Overall, the excellent thermal and mechanical properties, as well as significant biodegradability, of these copolyesters make them suitable to replace petroleum-based commercial polyesters, thereby offering innovative solutions to the problem of environmental pollution.
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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) | 0.000 | 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 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".