Self‐Immolative Polycarbamates From 4‐Hydroxybenzaldehyde, Vanillin, and Syringaldehyde
Bibliographic record
Abstract
ABSTRACT There is currently substantial interest in degradable polymers that can be prepared from renewable, bio‐based monomers. Lignin in particular is an attractive source for aromatic building blocks, as it is a waste product from the pulping process, and research is underway to improve processes to isolate molecules such as 4‐hydroxybenzaldehyde, vanillin, and syringaldehyde from lignin. Among the classes of degradable polymers, self‐immolative polymers (SIPs) can offer controlled, end‐to‐end depolymerization, making them attractive for a range of applications. Described here is the incorporation of 4‐hydroxybenzyl alcohol, vanillyl alcohol, and syringyl alcohol into SIPs. After initial attempts to synthesize polycarbonates, our efforts shifted to polycarbamates containing N,N ′‐dimethylethylenediamine spacers. The steric hindrance imparted by the methoxy groups on vanillyl alcohol and syringyl alcohol decreased the reactivity of the adjacent phenol and corresponding activated derivatives in the synthesis of the monomers, but after incorporation of the diamine spacer, the polycarbamate SIPs could be prepared with similar degrees of polymerization. The methoxy substituents slowed the depolymerization of the vanillyl alcohol and syringyl alcohol‐derived SIPs compared to the SIP derived from 4‐hydroxybenzyl alcohol. Meanwhile, the syringyl alcohol‐derived polymer exhibited decreased background degradation in the absence of end‐cap cleavage.
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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".