Anethole, a naturally occurring aromatic compound which can be extracted abundantly from plants like star anise, fennel and basil, has been conveniently transformed to a functional monomer in an overall yield of 81% via a two-step procedure.

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.

Vanillin has recently been prepared on a large scale from lignin, which becomes the second largest renewable resource. Because it has a naturally aromatic ring and an easily modified functional group, vanillin is considered as one of the ideal feedstocks for the synthesis of high-performance polymers. Based on this, there are a few investigations on low dielectric polymers derived from vanillin, and we have designed and synthesized a monomer containing cross-linkable vinyl and benzocyclobutene units starting from vanillin. This monomer can be easily thermally polymerized into a cross-linked network, which displays good thermostability with a 5% weight loss temperature (T 5d ) of up to 436 °C and a coefficient of thermal expansion (CTE) of 60.9 ppm/ °C. Moreover, no obvious glass-transition temperature (T g ) of the cross-linked network is observed from room temperature to 400 °C during the dynamic mechanical analysis (DMA). In addition, the DMA test indicates that the cross-linked network exhibits good mechanical properties with a storage modulus of up to 3.89 GPa at room temperature. Furthermore, the cross-linked network displays good dielectric properties with a dielectric constant (D k ) of less than 2.84 and a dissipation factor (D f ) of below 4.9 × 10 −3 for frequencies ranging from 0.15 to 20 MHz. At a high frequency of 5 GHz, the cross-linked network exhibits a D k of 2.81 and a D f of 6.79 × 10 −3 , respectively. When the cross-linked polymer is immersed in water at room temperature for 96 h, it shows a low water uptake of 0.44%. These results indicate that the new biobased thermosetting resin has potential applications as a matrix resin or an encapsulation material in the microelectronic industry.