Gel–Sol Transition of Vanillin-Based Polyimine Vitrimers: Imparting Vitrimers with Extra Welding and Self-Healing Abilities

Abstract

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.

Two luminescent film sensors constructed from new lanthanide coordination polymers for ratiometric detection of Zn2+ and NH3 in water and their white emission properties

“…5a to render a tensile strength of 45.2 MPa, which is better than that documented. 42 Beside the excellent mechanical property, EuL @PMMA and TbL @PMMA with 4.5% mass percentage exhibited high flexibility and transparency, as demonstrated in Fig. 5b and c.…”

Stimuli‐responsive mechanical properties in polymer glasses: challenges and opportunities for defense applications

“…In the past couple of years, others have adapted the original epoxy-alcohol vitrimers to bio-based systems with higher amounts of crosslinks by incorporating multifunctional epoxies with other multifunctional alcohol or anhydride [216][217][218][219] or amine crosslinking groups. [220][221][222][223][224] Overall, these systems resulted in reversible, recyclable, high-T g dynamic polymer networks synthesized from renewable resources with the goal of increasing the operational windows of bio-based systems. 204 Transamination.…”

“…Although similar to transesterification, transamination reactions include transamination of vinylogous urethanes, 225,226 diketoenamines 207,208 and imines. [220][221][222][227][228][229][230] Typically considered an associative dynamic reaction (Scheme 3), free primary amines attack either vinylogous urethane ⊎-carbons, diketoenamines or imine functional groups in a mechanism similar to that of transesterification. A wide range of amine hardeners appear in the literature producing a library similar to traditional epoxyamine systems, where concentration (network density) and chemical composition (energetics of bond exchange and entropy of polymer chains) affect T g and T v .…”

Recyclable, Biobased Photoresins for 3D Printing through Dynamic Imine Exchange

“…A few biobased CANs have been reported, usually consisting of associative bond exchange mechanisms, which are known as vitrimers. [23][24][25][26] Although a minority, there are some reports of 3D printed materials that take advantage of CANs, with direct ink writing (DIW) being the most used technique. 27,28 Nonetheless, a few reports that combine the use of VP and CANs have been documented.…”