Thermal Polymerization of Softwood Kraft Lignin: Enhanced Adhesion of Lignin-Phenol-Formaldehyde Blends
Bibliographic record
Abstract
High Resolution Image Download MS PowerPoint Slide Thermal polymerization improved the adhesion properties of softwood kraft lignin, making polymerized softwood kraft lignin a viable and sustainable partial substitute for phenol-formaldehyde resins used in engineered wood panels. This was confirmed by the increased shear strengths observed after pressing hardwood veneers with either alkaline aqueous lignin solutions or their blends with commercial phenol-formaldehyde resins. Plywood panels bonded with blends of polymerized kraft lignin and phenol-formaldehyde resins exhibited higher wood failure values compared with those bonded with phenol-formaldehyde resins alone. Extensive polymerization was achieved solely via nonoxidative thermal treatments. The impact of temperature and time on average molar mass, dispersity, and intrinsic viscosity was investigated by size-exclusion chromatography, revealing that the average molar mass of kraft lignin can be increased by more than 40 times its original value. Other critical parameters affecting the polymerization process such as pH and water content were identified, and their influence quantified. Hydroxyl content measured by 31 P NMR before and after polymerization suggests that the formation of ethers between phenols and benzylic hydroxyl groups is mainly responsible for the observed increase in molar mass.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 teacher head, 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".