The self‐healing mechanism of an industrial acrylic elastomer

Abstract

The self-healing materials attract a lot of attention as self-healing ability considerably improves reliability of service and extends the life time of materials. However, the present self-healing materials lack the mechanical strength and thus cannot be used in practical applications. The industrial elastomer (VHB 4910) is a strong polymer, which has been used as dielectric actuator. Surprisingly, we observed that VHB 4910 has autonomic self-healing ability. As this is an acrylic polymer, we analyzed the hydrogen bonding between carbonyl and hydroxyl groups and demonstrated that this bonding and the molecular chain entanglement contributes to its self-healing ability. The tensile test, X-ray diffraction (XRD), Raman, and Fourier transform infrared (FTIR) spectroscopy were employed to analyze the self-healing processes. This study provides an insight into the mechanism of self-healing behavior and ability of VHB 4910 to recover its strength.

Thermally assisted self‐healing polyurethane containing carboxyl groups

“…From the DSC results, we deduced that hydrogen bonding between PEG and carboxyl groups hinders the crystallization of PEG chains, so the mobility of the PEG chains increased. Flory's theory indicates that the mobility of molecular chains increases with the temperature . We noticed that the self‐healing property of this polymer should be assisted with heating, and the healing efficiency increased as the temperature increased [as shown in Figure (c)].…”

“…After cutting into two pieces, the cut faces of the sample will approach a new equilibrium state, which may cause the polymer to lose the ability to self‐heal. Furthermore, we tested the influence of waiting time on the self‐healing ability . We found that the polymer PEG6000‐20%‐MDI‐DMPA still demonstrated an excellent self‐healing ability even when the healing was conducted 72 h after cutting.…”

“…The noncovalent transient bonds include hydrogen bonds, metal bonds, ionomers, and π‐π interactions . Hydrogen bonds are widely used to design supramolecular materials, and the reversible and dynamic nature of the hydrogen‐bonding interaction endows materials with repeatable healing properties . Chen et al .…”

“…28 Hydrogen bonds are widely used to design supramolecular materials, and the reversible and dynamic nature of the hydrogen-bonding interaction endows materials with repeatable healing properties. [29][30][31][32][33] Chen et al 29 designed a hydrogenbonding brush polymer that self-assembles into a hard-soft microphase-separated system, showing spontaneous self-healing properties under ambient conditions. Cordier et al 31 created a rubber by hydrogen-bonding interaction between fatty acids and urea, which can be cut and repaired repeatedly at room temperature.…”

Do You Get What You See? Understanding Molecular Self‐Healing

“…Intrinsic self-healing polymers often rely on reversible chemical reactions allowing the material to transport matter into the damaged site enabling healing by subsequentc rosslinking the transported matter to the undamaged material. In this context,v ibrationals pectroscopy like, for example, IR-absorption [17,18] or linear Raman [19,20] spectroscopy are very powerful tools to characterize self-healing materials on am olecular level. Molecular interactions and reactions utilized for the crosslinking process in intrinsic self-healing polymers [2,6] include but are not limited to hydrogen bonds, [7] metal-ligand interactions, [8] halogen bonds, [9] Diels-Alder reactions [10,11] as well as thiol-ener eactions.…”