Self‐Healing Polybutadienes Formed through Sigmatropic Rearrangement and Stratified H‐Bonding for Use in Polymer‐Bonded Explosives

Abstract

The accomplishment of self‐healing polybutadienes (PB) is decisive for multitude of aerospace applications. We here present the first‐time report on a self‐healing PB derived from a blend of allyloxy end functionalized PB elicited through intramolecular thermally activated sigmatropic Claisen rearrangement coupled with stratified hydrogen bonding for use in polymer bonded explosives (PBX). Heteronuclear Single Quantum Correlation (HSQC), Heteronuclear Multiple Bond Coherence (HMBC), Total Correlation Spectroscopy (TOCSY) and Fourier Transform Infrared spectroscopy (FTIR) Spectroscopy were utilized to confirm the mechanistic aspects of the rearrangement for the proposed application. The mechanism of self‐healing is further elucidated using density functional theory (DFT) computations and confirmed through Raman spectroscopy. The biphasic polymer network architecture is disclosed through two glass transitions at −54 °C and 15–25 °C, as confirmed by Dynamic Mechanical Analysis (DMA) and Atomic Force Microscopy (AFM). The polymer exhibited healing efficiency of 85 % suitable for adhesive or coating applications. Self‐healing in bonding formulations of insensitive polymer bonded explosives was also expedited which exhibited a healing efficiency of 49–54 %.