Vitrimers are cross-linked networks through reversible dynamic covalent bonds. Usually, self-healing of vitrimers are realized by rearrangement of the networks under high temperature (>150 °C) and high pressure. The vitrimers that can be recovered under milder conditions have rarely been reported. In this work, interesting solvent-induced recyclable polyimine vitrimers derived from vanillin were first developed. Their recovery processes can be carried out through an unexpectedly fast and unusual gel–sol transition (less than 30 min) with the help of a few solvents. Thanks to this special ability, the polyimine vitrimers not only can be reprocessed by traditional hot-press and degradation, but also exhibit solvent-induced welding and self-healing abilities at room temperature. Moreover, aldehyde monomers can be recycled through chemical degradation without further separation in the mixture of recycled monomers, and the effects of aldehyde monomers on the properties of as-prepared polyimine vitrimers were first studied in detail.

Biomass-derived high-performance polymers have recently received much attention because they are easily available and renewable. More recently, researchers have been interested in low-dielectric polymers derived from biomass feedstock. These polymers display good dielectric properties and high thermostability, as well as good mechanical properties, implying that they have potential application in microelectronic industry, especially in fifth-generation communication (5G). This review summarizes recent progress in low dielectric polymers based on the biomass, including the synthesis and properties of different types of biomass resins such as epoxy resins, benzoxazine resins, benzocyclobutene resins, perfluorocyclobutane resins, cyanate eaters, polyester resins, phthalonitrile resins, and a functional maleimide.

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