Synthesis, Characterization and Thermal Properties of Intrinsic Self‐Healing Polyurethane Nanocomposites

Abstract

A hybrid thermo-reversible crosslinking polyurethane nanocomposite containing 0.5, 1, and 2 wt.% of nano-silica was prepared with three intrinsic self-healing bonds (reversible covalent bonds supported by intrinsic hydrogen bonds and dangling chains). Owing to the introduction of pseudo-tannin and polyester diol that could form phenol-urethane networks and using nano-silica that causes dangling chains and hydrogen bonds, the prepared polyurethanes are capable of being reversed at 110 °C and rejoin at low temperatures. Thermoset self-healing polyurethane nanocomposites are prepared from pseudo-tannin, nano-silica, and a urethane-based prepolymer. The investigations of chemical structure, self-healing behavior, and cross-link network are carried out by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) technique, and swelling test. dissociation of phenolic urethane at 110 °C was confirmed by temperature variable FTIR. By swelling test, it was found that the self-healing polyurethane nanocomposites with 0.5 wt.% of nano-silica have the most hard-domain, gel content, and crosslink density in the samples. DSC technique shows that polyurethane samples have two heat transfer transitions (dangling chains and self-healing). Thermogravimetric analysis (TGA) findings show that nanocomposites decompose at elevated temperatures than neat PU, and the rate of degradation diminishes as silica content increases.

Polysulfide polyurethane–urea-based dielectric composites with CeO2-loaded MXene exhibiting high self-healing efficiency

“…1b. Apparently, the peak at 3334 cm À1 is attributed to the stretching vibration of N-H, 27 2914 cm À1 and 2867 cm À1 belonging to the -CH 2 -stretching vibration, 28 and the two absorption peaks at 1660 cm À1 and 1586 cm À1 correspond to the amide I band (CQO bond stretching vibration) and the amide II band (N-H bond stretching vibration), respectively. 29 Furthermore, the peaks at 1540 cm À1 , 1461 cm À1 , and 1019 cm À1 belong to the bending vibration of -CO-NH-, the bending vibration of the C-N bond, and the absorption peak of the stretching vibration of the ether bond (C-O-C) in LP-55, respectively.…”