Designing a 3D structure and a self‐healing technique for advanced polymer composites with outstanding mechanical properties and healing ability

Abstract We designed three‐dimensional (3D) structures through a combination of glass fiber cloth and in situ formation of nano polyphenylene oxide (PPE) fibers during the fabrication process of thermosetting cyanate ester/bismaleimide composites and developed a self‐stitching technique based on PPE fiber and interpenetrating polymer networks (IPNs) for aiding the crack self‐healing. The building of 3D structure effectively improves the interface interaction between fiber and matrix and suppresses the crack propagation process in composite, leading to significant enhancement in the mechanical properties. When PPE content is 20%, the interlaminar shear strength, flexural strength, impact strength, and tensile strength of the resulting composite are 98%, 74%, 95%, and 101% higher than those of the composite without PPE. The resulting composites possess excellent thermomechanical and lower dielectric properties. Because IPNs within composites can create interspaces and easily deform above glass‐transition temperature, PPE components may penetrate through the interspaces under thermal expansion force, and the contraction stresses of polymers generate strong locking effects in composite after cooling to room temperature, then the crack surfaces of composites can be stitched by PPE fibers, significantly recovering the mechanical properties. The healing efficiency of the composite with 30% PPE after impact and then heating at approximately 280°C can reach 96%. Highlights 3D structures were constructed during the fabrication process of glass‐fiber‐reinforced thermosetting cyanate ester/bismaleimide composite. A self‐stitching technique was developed for aiding the crack self‐healing of composite. 3D structures significantly improved the interface interaction between fiber and matrix in laminated composite. The mechanical properties of the resulting composite could be significantly improved by 3D structures. The healing efficiency of the healed composite could reach 96%.