排序方式: 共有2条查询结果,搜索用时 3 毫秒
1
1.
Dr. Douriya Z. Khedaioui Camille Tribout Julie Bratasanu Dr. Franck D'Agosto Dr. Christophe Boisson Dr. Damien Montarnal 《Angewandte Chemie (International ed. in English)》2023,62(12):e202300225
The activity of various additives promoting siloxane equilibration reactions is examined and quantified on model compounds. We found in particular that the “superbase” phosphazene derivative P4-tBu can promote very fast exchanges (a few seconds at 90 °C) even at low concentration (<0.1 wt %). We demonstrate that permanent silicone networks can be transformed into reprocessable and recyclable dynamic networks by mere introduction of such additives. Annealing at high temperature degrades the additives and deactivates the dynamic features of the silicone networks, reverting them back into permanent networks. A simple rheological experiment and the corresponding model allow to extract the critical kinetic parameters to predict and control such deactivations. 相似文献
2.
Douriya Khedaioui Christophe Boisson Franck D'Agosto Damien Montarnal 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(44):16030-16036
While the introduction of polymers into aerogels strongly enhances their toughness, truly elastic monolithic aerogels which restore their dimensions upon extensive compression are still challenging to synthesize. In this context hydrophobic semi‐crystalline polymers with low glass transition temperatures, and combined stiffness and flexibility, have only recently attracted attention. Shown here is that polyethylene aerogels with a low density, and combined chemical crosslinking and high crystallinity, display high moduli and excellent mechanical resilience. To maximize the crystallinity of these aerogels while maintaining a high crosslinking density, polyethylene networks with well‐defined segments were synthesized by hydrosilylation crosslinking of telechelic, vinyl‐functionalized oligomers obtained from catalyzed chain‐growth polymerization. Recoverable deformations both above and below the melting temperature of polyethylene affords remarkable shape‐memory properties. 相似文献
1