Composite sepiolite/chitosan layer-by-layer coated flexible polyurethane foams with superior mechanical properties and energy absorption

• Published in: Composite structures Vol. 322; p. 117419
• Main Authors: Ji, Wenfei, Zhang, Qicheng, Alvarez-Borges, Fernando, Yuan, Guanjie, Van Duijneveldt, Jeroen, Briscoe, Wuge H., Scarpa, Fabrizio
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.10.2023
• Subjects: damping; energy dissipation; layer-by-layer assembly; nanocomposite coatings; Polyurethane foam; stiffness; energy dissipation; nanocomposite coatings; layer-by-layer assembly; damping; stiffness; Polyurethane foam
• ISSN: 0263-8223; 1879-1085
• DOI: 10.1016/j.compstruct.2023.117419

[Display omitted] •Design of polyurethane foam composites with naturally abundant sepiolite nanoclay and biopolymer chitosan via simple and facile layer-by-layer coatings.•The coatings reinforce the foam skeleton, resulting in a 200% improvement of the Young’s and dynamic moduli compared to untreated foams.•Transmitted impact forces are reduced by 50% with six bilayer coatings, demonstrating an improved impact energy dissipation.•Detailed discussions are provided about the deformation mechanisms and enhancement of the quasi-static and dynamic mechanical performance. Flexible polyurethane foam composites with enhanced stiffness and energy dissipation have been prepared via a facile layer-by-layer assembly approach. The composite foams consisted of naturally abundant nanoclay/chitosan multilayers (up to six) deposited onto the foam struts via dip-coating. The nanoclay/chitosan polyurethane foams were characterised using infrared spectroscopy, scanning electron microscopy, elemental mapping and μ-CT scanning. Quasi-static mechanical compression of the foams with 6 bilayers showed a 202% increase in the stiffness and a 33% enhancement in the damping loss factor compared to the uncoated pristine foam. Vibration transmissibility tests showed that the dynamic modulus of the 6-bilayer coated foams was 3 times that of the pristine foam. Remarkably, impact tests registered a 50% decrease in the transmitted impact force of these sepiolite/chitosan layer-by-layer coated open cell polyurethane foams, demonstrating their improved energy dissipation capability compared to other nanocoated foams in open literature.