Making Insoluble Polymer Networks Malleable via Olefin Metathesis

Abstract

Covalently cross-linked polymers have many technological applications for their excellent properties, but they suffer from the lack of processability and adaptive properties. We report a simple, efficient method of generating adaptive cross-linked polymers via olefin metathesis. By introducing a very low level of the Grubbs' second-generation Ru metathesis catalyst, a chemically cross-linked polybutadiene network becomes malleable at room temperature while retaining its insolubility. The stress relaxation capability increases with increasing level of catalyst loading. In sharp contrast, catalyst-free control samples with identical network topology and cross-linking density do not show any adaptive properties. This chemistry should offer a possibility to combine the dimensional stability and solvent resistance of cross-linked polymers and the processability/adaptibility of thermoplastics.

Enhancing Mechanical Performance of a Covalent Self-Healing Material by Sacrificial Noncovalent Bonds

“…32,36,37 We chose to copolymerize 3 with CO to control the amide mole fraction in ACON (Scheme 1b). Following our reported protocol, 38 the ACON polymer was cross-linked by radical reaction and G2 was incorporated by swelling ( Table 1. The molecular weights for the hydrogen bonding and control polymers are very close.…”

Vitrimers: permanent organic networks with glass-like fluidity

“…8). 40,41 This catalyst was used because of its superior stability towards air and moisture and its good functional group compatibility, as compared to more classical metathesis catalysts. 42 Networks were first prepared through free radical cross-linking of polybutadiene initiated by benzoyl peroxide.…”

Chemical control of the viscoelastic properties of vinylogous urethane vitrimers

“…Currently, as recently reviewed by our group9, only a limited number of associative exchange chemistries101112131415161718192021222324 have been explored in the context of vitrimers, and one of the main challenges is the precise control of the exchange kinetics. Although Leibler and co-workers demonstrated that epoxy-based transesterification vitrimers can be controlled by changing catalysts8, the exchange reaction remains slow and high catalyst loadings and temperatures are required to enable processing in a reasonable timeframe678.…”