We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Self-Extinguishing Alginate-Based Xerogel Foams for Thermal Insulation
Summary
Scientists created a new insulation foam made from seaweed-based material (alginate), crushed volcanic rock, and chitosan (a substance derived from shellfish shells) as a plant- and ocean-based alternative to plastic foam insulation used in buildings. This foam insulates just as well as conventional versions, resists catching fire, and is sturdy enough to hold its shape — all while being made from renewable materials instead of petroleum. For consumers, this matters because it points toward safer, less toxic building materials that could reduce reliance on fossil-fuel-based plastics, which shed microplastics and can release harmful fum
Biopolymer-based porous materials are attracting increasing interest as sustainable alternatives to conventional thermal insulation foams; however, achieving low thermal conductivity together with adequate mechanical performance and fire response remains challenging. Building on previous formulation screening, this study investigates alginate-expanded perlite xerogel foams modified with chitosan and glycerol for thermal insulation applications. Foams were prepared via in situ CO2 foaming and Ca2+ crosslinking, followed by mild oven drying. The effects of expanded perlite (9–12%), glycerol (0–10%), and chitosan (0–1%) were systematically investigated. All formulations exhibited low thermal conductivity (0.0467–0.0525 W m−1 K−1) and UL-94 V-0 self-extinguishing behavior. Incorporation of dispersed chitosan significantly enhanced compressive strength, reaching 263 kPa at 10% strain, within the range of commercial polymer foams. Image analysis and SEM showed that chitosan suppressed bubble coalescence, reduced large-pore fractions, and improved particle coverage, yielding structurally coherent matrices. Glycerol primarily acted as a plasticizer, improving the dimensional stability, but contributing less to pore refinement. The developed foams combine competitive thermal insulation performance, self-extinguishing behavior, and mechanical properties suitable for self-supporting insulation applications through a simple, water-based manufacturing route, highlighting their potential as sustainable alternatives to conventional fossil-based insulation materials for building applications.