Hierarchically Porous Cellulose–Lignin–Chitosan Aerogels Reinforced with APP@SiO₂–MEL Hybrids for High-Performance Flame Retardancy

Hierarchically Porous Cellulose–Lignin–Chitosan Aerogels Reinforced with APP@SiO₂–MEL Hybrids for High-Performance Flame Retardancy | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Hierarchically Porous Cellulose–Lignin–Chitosan Aerogels Reinforced with APP@SiO₂–MEL Hybrids for High-Performance Flame Retardancy Lei Chen, XiaoDong Qian, Haiyan Wang, Congling Shi, Mei Wan, Jingyun Jing, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7580956/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Developing lightweight, eco-friendly, and fire-safe materials is essential for sustainable engineering applications. Here, we report a structurally engineered biomass aerogel constructed from a cellulose–lignin–chitosan skeletal framework reinforced with nanoencapsulated P/N–Si flame-retardant hybrids. Ammonium polyphosphate(APP) was encapsulated within a silica shell and combined with melamine (MEL) to form a multifunctional flame-retardant phase uniformly anchored onto the bio-derived network. The synergistic structural–chemical design yielded a robust, highly porous microarchitecture with enhanced hydrophobicity (water contact angle up to 73.4°), improved thermal stability (T_max increased from 195°C to 234°C), and outstanding flame retardancy (> 74% reduction in peak heat release rate), while maintaining low bulk density. Mechanistic studies reveal that during combustion, APP@SiO₂–MEL promotes phosphorylation–dehydration reactions, triggering early char nucleation and catalytic graphitization in the condensed phase. The resulting P/N-rich, SiO₂-reinforced intumescent char forms a cohesive barrier with an “indirect path” effect, significantly slowing down the transport of heat and flammable volatiles. Simultaneously, released P = O• radicals quench flame-propagating radicals in the gas phase, further suppressing combustion. This dual-phase synergistic mechanism effectively preserves structural integrity under fire exposure. This work provides a scalable, environmentally friendly strategy for producing high-performance, fire-safe biomass aerogels, offering significant potential for applications in thermal insulation, construction safety, and energy storage protection. The combination of renewable bio-based matrices and advanced flame-retardant nanotechnology represents a promising pathway toward next-generation sustainable fire-protection materials. Cellulose lignin chitosan network (CSF) APP@SiO₂ MEL (nanoencapsulated P/N Si flame retardant) Low thermal conductivity Indirect path effect Eco-friendly aerogel Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7580956","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":541190557,"identity":"fcd702bd-3d08-4999-af3a-c8650aff0a1d","order_by":0,"name":"Lei Chen","email":"","orcid":"","institution":"China University of Mining \u0026 Technology (Beijing)","correspondingAuthor":false,"prefix":"","firstName":"Lei","middleName":"","lastName":"Chen","suffix":""},{"id":541190558,"identity":"fa206ef2-7618-4a2b-9742-cc52fd27e937","order_by":1,"name":"XiaoDong 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Here, we report a structurally engineered biomass aerogel constructed from a cellulose\u0026ndash;lignin\u0026ndash;chitosan skeletal framework reinforced with nanoencapsulated P/N\u0026ndash;Si flame-retardant hybrids. Ammonium polyphosphate(APP) was encapsulated within a silica shell and combined with melamine (MEL) to form a multifunctional flame-retardant phase uniformly anchored onto the bio-derived network. The synergistic structural\u0026ndash;chemical design yielded a robust, highly porous microarchitecture with enhanced hydrophobicity (water contact angle up to 73.4\u0026deg;), improved thermal stability (T_max increased from 195\u0026deg;C to 234\u0026deg;C), and outstanding flame retardancy (\u0026gt;\u0026thinsp;74% reduction in peak heat release rate), while maintaining low bulk density. Mechanistic studies reveal that during combustion, APP@SiO₂\u0026ndash;MEL promotes phosphorylation\u0026ndash;dehydration reactions, triggering early char nucleation and catalytic graphitization in the condensed phase. The resulting P/N-rich, SiO₂-reinforced intumescent char forms a cohesive barrier with an \u0026ldquo;indirect path\u0026rdquo; effect, significantly slowing down the transport of heat and flammable volatiles. Simultaneously, released P\u0026thinsp;=\u0026thinsp;O\u0026bull; radicals quench flame-propagating radicals in the gas phase, further suppressing combustion. This dual-phase synergistic mechanism effectively preserves structural integrity under fire exposure. This work provides a scalable, environmentally friendly strategy for producing high-performance, fire-safe biomass aerogels, offering significant potential for applications in thermal insulation, construction safety, and energy storage protection. 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