Reactive Polyanions Based on Poly(4,4-dimethyl-2-vinyl-2-oxazoline-5-one-<i>co</i>-methacrylic acid)
Bibliographic record
Abstract
The formation of reactive polyanions by semibatch copolymerization of 4,4-dimethyl-2-vinyl-2-oxazoline-5-one (VDMA) and methacrylic acid (MAA) by both free radical and photoinduced radical polymerization is described. The reactivity ratios of these two monomers were determined to be 1.36 and 0.41 for r 1 (VDMA) and r 2 (MAA), respectively, using 1 H NMR spectroscopy. During the free radical copolymerization of a 50:50 VDMA:MAA copolymer (PMV 50 ) in anhydrous DMSO or THF at 60 °C, up to 40% of the azlactone groups in the copolymer are hydrolyzed by water formed largely by conversion of methacrylic acid diads into cyclic anhydride. Storage in organic solutions leads to further transhydration, while solid PMV 50 is stable for at least 6 months at room temperature. Increasing the VDMA comonomer content reduces this transhydration, likely through decreasing the incidence of methacrylic acid diads in the backbone. Alternatively, conducting the copolymerization at 20 °C using photoinitiation is also effective at suppressing this transhydration. The resulting reactive polyanions bind under physiological conditions to poly- l -lysine-coated calcium alginate hydrogel beads and spontaneously cross-link with the polyamine to form covalent networks of interest for long-term therapeutic cell encapsulation. This represents the first such use of a VDMA-containing polyanion in aqueous environments. The copolymers were characterized by 1 H NMR, quantitative 13 C NMR, 13 C DEPT-135 NMR, and FT-IR spectroscopies as well as by elemental analysis.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 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".