Homogeneous Hydrogenation Art of Nitrile Butadiene Rubber: A Review
Bibliographic record
Abstract
Hydrogenation of nitrile butadiene rubber (NBR) is an important research topic in the field of chemical modification of unsaturated polymers. This review provides an overview of the fundamental data, challenges, and recent advances in the research area of homogeneous hydrogenation of NBR. Besides NBR and its hydrogenation product HNBR, some other important elastomers such as styrene butadiene rubber (SBR), polybutadiene rubber (BR), polystyrene-b-polybutadiene-b-polystyrene (SBS block copolymer), and natural rubber (NR) were also involved for the related hydrogenation reactions and characterization. A brief comparison of hydrogenation catalysts including the heterogeneous and homogeneous catalysts was first conducted and the importance of rhodium (Rh) complex catalysts for homogeneous hydrogenation of elastomers was addressed. This article continued to discuss the reaction pathways for realization of the homogeneous hydrogenation of NBR. This was followed by an examination of the microstructures and characterization techniques of NBR and HNBR. After that the recovery/recycle of precious metal catalysts from the reaction substrate, which have been drawing much attention from industrial manufacturers, was reviewed and highlighted in this article. The applications of HNBR were then summarized. In the end, future research directions were suggested.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".