Synthesis, Bromination and Cure of Isobutylene/Isoprene/P-Methylstyrene and Isobutylene/Isoprene/Styrene Terpolymers
Bibliographic record
Abstract
Abstract High molecular weight isobutylene/isoprene/p-methylstyrene and isobutylene/isoprene/styrene terpolymers containing up to 10.6 mol% p-methylstyrene and 3.6 mol% styrene were synthesized using “H2O”/AlCl3 as an initiator/coinitiator system in methylchloride at -95 °C. p-Methylstyrene was found to be uniformly distributed in the chains due to its similar reactivity to isobutylene. In contrast, styrene had a lower reactivity than isobutylene or even isoprene, resulting in low conversion of the styrene monomer. The reactivity ratios obtained were in good agreement with the published values. Up to about 3 mol% styrenic monomer content, the Tg of the terpolymers showed no significant increase. The isoprene units of the terpolymers were brominated by the conventional bromination technique. During bromination, some of the aromatic rings also underwent bromination. The extent of this reaction was found to be much lower in the case of p-methylstyrene than in the case of styrene. The brominated terpolymers were cured using ZnO. The brominated terpolymers displayed much faster cure, higher maximum torque and modulus at the same brominated isoprene concentration than brominated copolymers of isobutylene and isoprene, indicating that the aromatic rings participate in the cure. The brominated terpolymers showed an increased resistance to hot air aging, compared to brominated polymers containing no styrenic termonomer.
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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 | 0.001 |
| 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".