Fabrication of Polyimide Aerogels Cross-Linked by a Cost-Effective Amine-Functionalized Hyperbranched Polysiloxane (NH<sub>2</sub>–HBPSi)
Bibliographic record
Abstract
Polyimide (PI) aerogels were prepared from anhydride end-capped polyamic acid oligomers cross-linked by a low-cost lab-made amine-functionalized hyperbranched polysiloxane macromer (NH 2 –HBPSi). NH 2 –HBPSi was synthesized via the hydrolysis–condensation reaction between phenyltrimethoxysilane, tetraethoxysilane, and γ-aminopropylmethyldiethoxysilane, which are all cheap commercially available silane-coupling agents. To determine the effects of the NH 2 –HBPSi cross-linker on the formation and properties of aerogels, two different PI oligomers, synthesized from relatively flexible 4,4′-oxidianiline and rigid-rod 2,2′-dimethylbenzidine, were investigated. The resulting PI aerogels showed comparable properties with the triamine cross-linked PI aerogels, such as low densities (0.12 to 0.20 g cm –3 ), high BET specific surface areas (279 to 460 m 2 g –1 ), low thermal conductivities (29–32 mW m –1 K –1 ), and excellent mechanical and thermal properties across the range of NH 2 –HBPSi cross-linker concentrations used (2.5 to 12.5 wt %). Moreover, the thermal insulation, dielectric, and CO 2 uptake performances were also investigated, demonstrating the broad range of potential applications for these multifunctional cross-linked PI aerogels. Considering the low-cost and facile synthesis for this NH 2 –HBPSi macromer cross-linking agent, we anticipate that this work can overcome the drawbacks of expensive conventional PI cross-linkers and offer a simple approach to produce low-cost PI aerogels at scale.
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 | 0.000 |
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".