Network Design to Control Polyimine Vitrimer Properties: Physical Versus Chemical Approach

Abstract

A family of biobased polyimine elastomeric vitrimers was synthesized by reactions between di-and trifunctional polyetheramines and a furan-based dialdehyde. By varying the triamine to diamine ratio and the molar mass of the diamine, a set of cross-linked networks with similar chemical structures but different cross-link densities was obtained. All these materials exhibit a vitrimeric behavior because of the dynamic nature of the imine bonds. This fundamental study clearly reveals that the crosslink density has a drastic effect on the relaxation properties of the vitrimers. For instance, the relaxation times and the activation energies reduced when the cross-link density of the vitrimer networks decreased. This shows that the relaxation properties of vitrimers can be controlled by the sole modification of the network physical properties without the introduction of a catalyst, a change in chemical structure, or the introduction of additional chemical groups. In addition, a fast dual relaxation process has been clearly evidenced during stress relaxation experiments, which could potentially lead to double relaxation modes based on supramolecular interactions. The selective solubility of these polyimine networks was also demonstrated, opening interesting possibilities for chemical recycling while still offering robustness against aggressive conditions such as highly basic solutions. Finally, the dynamic properties and the high thermal stability of the designed polyimine networks provide an interesting reprocessability and tunable mechanical properties, showing the versatility of this sustainable family of vitrimer materials.

Molecular control over vitrimer-like mechanics – tuneable dynamic motifs based on the Hammett equation in polyimine materials

“…60,61 Polyimine materials have been studied for a broad variety of applications, like re-resistance, 62,63 3D printing, 64 sensing, 65,66 CO 2 capture, [67][68][69] antibacterial coatings, 70 and in the production of electronic skins. 71 Some attempts in tuning the material properties of polyimines have been documented: for example by tuning the degree of crosslinking, 72,73 sub-chain composition, 36,59,74,75 solvent, 34,76 or metal-coordination. 35,65,77 These attempts have produced a number of interesting results, but focussed more on the composition of the polymer matrix rather than on the dynamics of the imine bond itself.…”

Effect of precise linker length, bond density, and broad temperature window on the rheological properties of ethylene vitrimers

“…The rekindled interest in these networks in the last decade has led to numerous articles on vitrimers for shape memory polymers, [35][36][37] shockwave dissipation, 38 flame retardants, 39 and solid electrolytes. 40 While initial work was focused on stress relaxation times and self-healing as a function of bond chemistry and polymer backbone, recent work has moved to investigating the effects of crosslink density, 41,42 defects 43 and solvent concentration 44 on the rheological properties of vitrimers.…”

Malleable and recyclable imide–imine hybrid thermosets: influence of imide structure on material property

“…Furthermore, all the polymers showed high tensile strength (58-79 MPa) and tensile modulus (1.79-2.49 GPa), which are comparable to many existing polyimides (tensile strength 70-100 MPa, tensile modulus 1.5-3.0 GPa) 29 but superior to many polyimines 25,26,[37][38][39][40] . These results indicate that the hybridization by integrating the imine bond into the polyimide backbone does not adversely lead to reduction in mechanical properties of polyimides.…”