Wide-temperature-range self-healing polymer based on supramolecular coordination for improving key mechanical properties of propellants

Abstract

Composite solid propellants still face critical issues such as matrix strength degradation, grain structure failure, and interfacial debonding, which severely compromise their reliability and operational safety. Developing polymers with superior self-healing capabilities across a wide temperature range and enhanced mechanical properties as propellant matrices, as well as synthesizing self-healing propellants, holds significant promise for addressing these challenges. In this work, by precisely controlling the quantity and spatial arrangement of ligands through analysis of the bond strength and reactivity of dynamic coordination bonds, we successfully fabricated a mechanically reinforced self-healing polymer with broad temperature adaptability. This polymer exhibits a self-healing efficiency exceeding 80 % over a wide temperature range. Concurrently, its mechanical strength is markedly improved, achieving a fracture elongation of over 1600 %. When formulated into propellant samples, the propellant demonstrates exceptional mechanical performance, without interfacial debonding problem during tensile testing. Furthermore, the incorporation of self-healing functionality shows no adverse effects on other critical properties of propellant. This work also elucidates the healing mechanisms of the polymer and propellant system, as well as the principles underlying their mechanical reinforcement. The developed polymer exhibits high feasibility for propellant applications, offering a novel strategy for advancing research on self-healing composite solid propellants.