Stretchable, Ultratough, and Intrinsically Self‐Extinguishing Elastomers with Desirable Recyclability

Abstract

Advanced elastomers are increasingly used in emerging areas, for example, flexible electronics and devices, and these real‐world applications often require elastomers to be stretchable, tough and fire safe. However, to date there are few successes in achieving such a performance portfolio due to their different governing mechanisms. Herein, a stretchable, supertough, and self‐extinguishing polyurethane elastomers by introducing dynamic π–π stacking motifs and phosphorus‐containing moieties are reported. The resultant elastomer shows a large break strain of ≈2260% and a record‐high toughness (ca. 460 MJ m−3), which arises from its dynamic microphase‐separated microstructure resulting in increased entropic elasticity, and strain‐hardening at large strains. The elastomer also exhibits a self‐extinguishing ability thanks to the presence of both phosphorus‐containing units and π–π stacking interactions. Its promising applications as a reliable yet recyclable substrate for strain sensors are demonstrated. The work will help to expedite next‐generation sustainable advanced elastomers for flexible electronics and devices applications.

Poly(vinyl alcohol)/Laponite/Layered Double Hydroxide/Hydroxyapatite Nanocomposite Hydrogels for Stimulus-Responsive Devices

“…Polymer networks in most hydrogels are highly flammable, which makes it unsuitable for them to serve as fire-resistant agents . Recently developed high-performance fire-resistant hydrogels usually contain metallic elements, sulfur, phosphorus, and/or halogen elements, which raise potential environmental pollution issues . Distinctively, our proposed PVA/LHL nanocomposite hydrogel displayed nice fire-resistance properties.…”

Robust Epoxy Vitrimer with Simultaneous Ultrahigh Impact Property, Fire Safety, and Multipath Recyclability via Rigid-Flexible Imine Networks

“…The vanillin-derived siloxane-containing Schiff base epoxy monomer VNTMSi-EP was prepared through a two-step process, as depicted in Scheme c. To avoid oligomerization, glycidylation of vanillin was first carried out with excess epichlorohydrin in the presence of a phase transfer catalyst, followed by the addition of an alkaline aqueous solution of sodium hydroxide, the related reaction mechanisms of which have been extensively studied. − Then, VNTMSi-EP was then prepared through a condensation reaction between VN-EP and BATMSi. Figures S1–S4 confirm the successful synthesis of VN-EP and VNTMSi-EP.…”

Facile Synthesis of Phosphorus-Free Biobased Epoxy Resin with Exceptional Flame Retardancy, Mechanical Properties, and Heat Resistance

“…Second, the in situ-generated Schiff bases can self-cross-link with aryl groups to form a dense carbon layer at high temperatures . The high char yield of PGE/DDS endows it with excellent flame retardancy as it can serve as a protective layer to reduce the flammable gas release and protect the inner substrate from flame erosion. − In order to visually observe the char carbonization capacity, cubic samples of the two resins were conducted to calcinate from room temperature to 600 °C in a N 2 atmosphere and held at 600 °C for 1 h. As shown in Figure b,c, DGEBA/DDS exhibits a hollow and fractured morphology after calcination, indicating the char layer of DGEBA/DDS is mechanically poor. The interior combustion gas breaks through the char layer, exposing the internal epoxy substrate to flame attack.…”