A lightweight porous shear stiffening composite foam with excellent mechanical–thermal coupling protection performance

Abstract

The safeguarding performance against complex stimuli such as thermal shock is very critical for the welfare of humans and equipment. Constructing multifunctional mechanical–thermal coupling protective composites through structural design remains a formidable challenge. In this work, a SSE-EVA foam (SEF) was synthesized by integrating a shear stiffening elastomer (SSE) with an ethylene-vinyl acetate (EVA) copolymer through a foaming process. Characterized by its low density (0.38 g cm⁻³) and reduced thermal conductivity (0.121 W m⁻¹ K⁻¹), SEF exhibited excellent thermal protection and provided effective insulation across a broad temperature spectrum, ranging from −5 to 150 °C. Additionally, its outstanding mechanical properties conferred upon SEF a high compression resilience (95.2%) and robust stability, as evidenced by its ability to withstand 1000 compression cycles and extended exposure to air for up to 18 weeks. More importantly, SEF could dissipate 3.17 kN impact force without structural damage under cyclic shock stimulations, showing grand impact resistance. In a further enhancement, paraffin wax (PW) was incorporated into SEF, bestowing the resultant composite (SEFP) with heat storage capabilities and exceptional thermal management performance. The versatile and lightweight SEF emerges as a promising candidate for applications in fire protection, shock resistance, and thermal camouflage.