A robust self-healing polyurethane elastomer: From H-bonds and stacking interactions to well-defined microphase morphology

Abstract

Self-healing materials have attracted considerable attention because of their improved safety, lifetime, energy efficiency and environmental impact. Supramolecular interactions have been extensively considered in the field of self-healing materials due to their excellent reversibility and sensitive responsiveness to environmental stimuli. However, development of a polymeric material with good mechanical performance as well as self-healing capacity is very challenging. In this study, we report a robust self-healing polyurethane (PU) elastomer polypropylene glycol-2-amino-5-(2hydroxyethyl)-6-methylpyrimidin-4-ol (PPG-mUPy) by integrating ureidopyrimidone (UPy) motifs with a PPG segment with a well-defined architecture and microphase morphology. To balance the self-healing capacity and mechanical performance, a thermal-triggered switch of H-bonding is introduced. The quadruple H-bonded UPy dimeric moieties in the backbone induce phase separation to form a hard domain as well as enable further aggregation into microcrystals by virtue of the stacking interactions, which are stable in ambient temperature. This feature endows the PU with high mechanical strength. Meanwhile, a high healing efficiency can be realized, when the reversibility of the H-bond was unlocked from the stacking at higher temperature. An optimized sample PPG 1000-mUPy 50% with a good balance of mechanical performance (20.62 MPa of tensile strength) and healing efficiency (93% in tensile strength) was achieved. This strategy will provide a new idea for developing robust self-healing polymers.

A Robust and High Self‐Healing Efficiency Poly(Urea‐Urethane) Based on Disulfide Bonds with Cost‐Effective Strategy

“…Moreover, SPU showed a slow decline of storage modulus and a slight transition of tan δ corresponding to the T g of the soft segments, which means the existence of microphase separation in the SPU sample. It is worth mentioning that when the temperature was increased above 120 °C, the tan δ of SPU began to rise rapidly, which implied that the quadruple hydrogen bondings were rapidly dissociated …”

Star-Shaped Crosslinker for Multifunctional Shape Memory Polyurethane

“…As shown in Figure 1, PPG was selected because of excellent chain mobility and solubility [23]. The polymer synthesized by using tris(2-aminoethyl) amine as crosslinker exhibited better thermal stability and mechanical adjustability [24], so it was employed in synthesizing neat PU for comparison in this work.…”

“…Furthermore, cyclic triphosphazene derivatives with different substituents allow us to easily obtain multifunctional crosslinker to enhance the shape memory property of the resulting PU. It has been reported that chemical crosslinking of polymers leads to SMPs with robust shape memory, high thermal stability and chemical stability [22,23]. Here we successfully synthesized amine-terminated cyclophosphazene (ACP) by nucleophilic substitution on the phosphorus atom.…”

Synthesis and Characterization of Linear Polyisoprene Supramolecular Elastomers Based on Quadruple Hydrogen Bonding

“…This may be due to the fact that PI-UPy melted at high temperatures, and the crack was filled by a mobile phase. In addition, after cooling, it became a solid state, and hydrogen bonds were gradually formed to achieve the self-healing process [37]. To further reveal the hydrogen bonds in PI-UPy, the temperature-dependent FTIR spectra are presented in Figure 10.…”