Terpene-derived polyester-block-polycarbonates using metal-free catalysis
Bibliographic record
Abstract
Sustainable materials are a large research focus due to depleting resources and increasing environmental pollution. Therefore, bio-derived building blocks from renewable feedstocks are being pursued as an alternative to fossil-derivatives for producing polymers. Here, we have prepared a series of polyester and polyester-block-polycarbonate copolymers from a metal-free ring-opening copolymerization (ROCOP) of various terpene-derived cyclic anhydrides, epoxides (cyclohexene oxide (CHO) and propylene oxide (PO)), and carbon dioxide (CO2) under neat (solvent-free) conditions. Cyclic anhydrides were prepared via microwave-assisted Diels Alder reactions between terpenes and maleic anhydride (up to 90% yield). The ROCOP catalyst system consisted of triphenylborane (BPh3) with bis(triphenylphosphine)iminium chloride (PPNCl) and, after complete conversion of anhydride, resulted in polymers with moderate molecular weights (Mn up to 21 kDa), and good dispersities (between 1.05 and 1.75). Thermal analysis resulted in a single glass transition temperature (between 1.5 C and 101 C) indicating amorphic materials. 13C{1H} NMR spectroscopy revealed high stereoregularity with respect to substituent methyl groups and di-ester units and 2D DOSY NMR spectroscopy confirmed a single polymer chain was formed by sequential copolymerizations. Residual olefinic groups in the polymer backbone provides opportunity for post-polymerization functionalization and, therefore, further tailoring of macroscopic properties.
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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 | 0.001 |
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".