Correlation of molecular weight diversity and colloidal disability performance of anionic lignin derived polymer
Bibliographic record
Abstract
• Lignin-polymethacrylic acid polymers were synthesized with similar average molecular weights and charge densities. • Free radical polymerization (FRP) made lignin derived polymers with a wider molecular weight distribution than atom transfer radical polymerization (ATRP). • The flocculation performance of the ATRP polymers was better than that of FRP ones. • Molecular weight distribution of lignin-derived polymer impacts its flocculation performance remarkably. Polymerization is considered one of the valorization techniques of lignin for various applications. Generally, polymerization techniques affect the molecular structure of polymers. In this work, we evaluated a hypothesis that the polymerization strategy and, thus, the molecular weight distribution of lignin-derived polymers would impact their effectiveness as a colloidal disability agent (i.e., flocculant) for a suspension system. To achieve our goal, different lignin-polymethacrylic acid (PMAA) polymers were synthesized via free radical polymerization (FRP) and atom transfer radical polymerization (ATRP) techniques. The experiments were designed such that two sets of polymers with different molecular polydispersities but similar average molecular weights, charge densities, radii of gyration, and hydrodynamic diameters were obtained. Both systems developed colloidal destabilization mainly via bridging phenomenon. The flocculation performance of the ATRP-synthesized samples with narrower molecular weight distribution was notably better than that of FRP-induced samples. The rheological and flocculation analyses under different shear rates confirmed that the ATRP-induced sample promoted the entanglement of particles and had a higher flocculation efficiency. The flocculant prepared using the ATRP technique demonstrated a significantly lower optimal dosage, requiring only 0.4 mg per gram, compared to 25.6 mg per gram for the samples produced using the FRP method. Also, this sample produced stronger flocs with more re-flocculation tendency under different shear rates, while it generated larger flocs under stirring conditions. Such ATRP-derived flocs had an average chord length of approximately 60 μm, and those of FRP-based ones had a 30 μm chord length, while both FRP and ATRP polymers had 500 Da molecular weight. The results of this work confirmed that, while lignin-derived polymers can be an effective flocculant, strategies must be taken into account for generating lignin-derived polymers with a controlled and preferably narrow molecular weight distribution.
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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 | 0.001 |
| 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".