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Multifunctional Vitrimer-Like Polydimethylsiloxane (PDMS): Recyclable, Self-Healable, and Water-Driven Malleable Covalent Networks Based on Dynamic Imine Bond
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posted on 2019-01-10, 21:14 authored by Zhanbin Feng, Bing Yu, Jing Hu, Hongli Zuo, Jianping Li, Haibin Sun, Nanying Ning, Ming Tian, Liqun ZhangVitrimer
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.