Fabrication of Highly Thermally Resistant and Self‐Healing Polysiloxane Elastomers by Constructing Covalent and Reversible Networks

Abstract

The fabrication of self‐healing elastomers with high thermal stability for use in extreme thermal conditions such as aerospace remains a major challenge. A strategy for preparing self‐healing elastomers with stable covalent bonds and dynamic metal–ligand coordination interactions as crosslinking sites in polydimethylsiloxane (PDMS) is proposed. The added Fe (III) not only serves as the dynamic crosslinking point at room temperature which is crucial for self‐healing performance, but also plays a role as free radical scavenging agent at high temperatures. The results show that the PDMS elastomers possessed an initial thermal degradation temperature over 380 °C and a room temperature self‐healing efficiency as high as 65.7%. Moreover, the char residue at 800 °C of PDMS elastomer reaches 7.19% in nitrogen atmosphere, and up to 14.02% in air atmosphere by doping a small amount (i.e., 0.3 wt%) of Fe (III), which is remarkable for the self‐healing elastomers that contain weak and dynamic bonds with relatively poor thermal stability. This study provides an insight into designing self‐healing PDMS‐based materials that can be targeted for use as high‐temperature thermal protection coatings.

Multidynamic Poly(oxime–carbamate) Elastomers with Rosin Moieties

“…In particular, the Cu-RPOUT elastomer (0.3080 g, 40.0 mm (length) × 10.0 mm (width) × 0.7 mm (thickness)) could successfully lift a weight of 10 kg (Figure S4). Compared with existing elastomers based on metal coordination bonds, the Cu-RPOUT elastomer exhibits excellent mechanical strength (Figure b). − These results suggest that the mechanical properties of the material can be improved after the formation of multicross-linking structures (hydrogen, metal–ligand coordination, and oxime–carbamate bonds) in the material, suggesting that the hydrogen and metal–ligand coordination bonds can be used as dynamic cross-linking points to increase the cross-linking density of the material. , This leads to further energy dissipation, which leads to the strengthening and toughening of the elastomers …”

Kinetics and thermal properties of polydiethylsiloxane initiated by potassium trimethylsilanolate

“…Silicone rubber is a widely used heat‐resistant material 34–36 . The thermal degradation temperature of a material has a great influence on its application and processing.…”

Effect of Coordination Sacrificial Bond Strength on Toughening Properties of Polyesters

“…Inspired by Nature , where spider silks and mussel byssus are strong and tough materials, introducing weak interactions into a polymeric material can greatly improve its mechanical properties. − These weak interactions are defined as sacrificial bonds (SBs) since they are broken preferentially before covalent bonds, following the energy dissipation mechanism and releasing the hidden length of chains. − To now, a variety of weak bonds (interactions), including hydrogen bonds, − metal–ligand coordination bonds, − and ionic interactions, , have been utilized to be incorporated into polymers with good toughening effect. Among them, due to the available abundance of metal ions and ligands, the metal–ligand coordination bonds have attracted great research interests. − For example, by the incorporation of pyridine–Zn 2+ coordination bonds into butadiene–styrene–vinylpyridine vulcanizing rubber, the modulus, strength, and toughness increased several times without sacrificing the extensibility .…”