Molecularly engineered dual-crosslinked elastomer vitrimers with superior strength, improved creep resistance, and retained malleability

Abstract

It’s very challenging to fabricate elastomer vitrimers that are both robust and dimensionally stable in service. Toward this issue, we initiate a multi-phase design of elastomer vitrimers by incorporating quadruple...

Preparation of Styrene–Butadiene Rubber Vitrimers with High Strength and Toughness through Imine and Hydrogen Bonds

“…Compared with eSBR-HA 0.2 , new characteristic peaks appeared at 3307 and 1667 cm −1 in the spectra of ACM-modified SBR vitrimers, which was attributed to the stretching vibrations of N−H and C�O in amide groups, respectively (Figure 3a). 28,42 The signal intensity at 1667 cm −1 was significantly enhanced with the increasing ACM content. The formation of hydrogen bonding was further confirmed by variable temperature FT-IR.…”

“…The strengthening and toughening mechanism of hydrogen bonding is described in Figure . During stretching, hydrogen bonds can dissipate large amounts of energy and diminish the stress concentration through prior rupture and reversible dissociation and reassociation, contributing an interesting combination of high strength and toughness. ,,, The physical cross-linking of hydrogen bonding can increase the modulus of elastomers. To further evaluate the energy dissipation during stretching, cyclic tensile experiments were performed (Figure ).…”

“…However, unreinforced elastomers often present weak mechanical strength, and the dynamics of network reshuffling would lead to undesirable mechanical properties . Inspired by the structure of robust natural materials, introducing the supramolecular interactions into dynamic covalently cross-linked networks appears to be an attractive strategy to strengthen elastomer vitrimers without the expense of malleability. − Neal et al demonstrated that incorporating sacrificial hydrogen bonds could improve the mechanical properties of olefin-containing networks.…”

Phase separation in supramolecular and covalent adaptable networks

“…12(A) ). 168 SAXS confirmed that only when the hydrogen bonding motifs were installed, phase separation was observed ( Fig. 12(B) ).…”

“…Phase separation induced by other hydrogen-bonding moieties are seen more often in CANs. 168,169 Some specific dynamic covalent groups are also known to form hydrogen bonds themselves. Dynamic covalent pyrazole-urea groups are, for example, known for their reversible BERs, but also for their potential to form intermolecular hydrogen bonds.…”