Multifunctional Vitrimer-Like Polydimethylsiloxane (PDMS): Recyclable, Self-Healable, and Water-Driven Malleable Covalent Networks Based on Dynamic Imine Bond

Vitrimer is a new class of polymeric materials which can be reprocessed to any shape while being permanently cross-linked. We designed and synthesized a catalyst-free network with poly(dimethylsiloxane)etherimide (PDMS-NH2), terephthalaldehyde (TA), and tri(2-aminoethyl)amine (TREA) through the condensation reaction between amino groups and aldehyde groups. As a result of the exchange reaction of the dynamic imine bond obtained, this PDMS network exhibits the nature of vitrimer-like material, which is examined by solubility and stress-relaxation experiments, and the relaxation time is as short as 64 s at 130 °C. In addition, the vitrimer-like PDMS is malleable and capable of self-healing, and the mechanical properties can be maintained even after three consecutive breaking/mold pressing cycles. Especially, besides heating, this vitrimer-like PDMS can also be recycled and reshaped at ambient temperature due to the exchange reaction of dynamic imine bond when immersed in water, which will potentially lead to green processing of the elastomers.