In-situ packing self-intumescent aerogel particles in rigid polyurethane foam towards thermal insulation, flame retardance and smoke suppression

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2025-01, Vol.503, Article 158514
• Main Authors: Yu, Ning, Wang, Ting, Xu, Cheng-Xu, Gou, Xue, Zhan, Ying-Jiao, An, Wenli, Fu, Zhi-Cheng, Deng, Jinni, Zhao, Hai-Bo, Chen, Ming-Jun
• Format: Article
• Language: English
• Subjects: Aerogel; Flame retardance; Rigid Polyurethane foam; Thermal insulation
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.158514

The polyurethane composites with the unique “sea-island” pore structures are constructed via in-situ packing self-intumescence aerogel particles method, which leads to excellent flame retardancy and enhanced thermal insulation. [Display omitted] •Interfacial bonding and in-situ packing strategy was proposed to fabricate aerogel/rigid polyurethane foam (RPUF) composites.•The composite with “sea-island” pore structures manifests a reduced thermal conductivity by 21.6% compared with neat foams.•The aerogel particles enhance the flame retardance with reduced heat release (−38.0%) and smoke production (−54.0%)•The composites manifest enhanced compressive strength (+93.7 %). Rigid polyurethane foam (RPUF), a commonly employed thermal insulation material in buildings, is highly flammable, however, incorporating flame-retardant additives or fillers is significantly limited by their incompatibility, low effectiveness and negative impact on thermal insulation properties. Herein, a novel and simple interfacial bonding and in-situ packing strategy has been proposed to introduce self-intumescent biomass aerogel particles into RPUF. The result aerogel/RPUF composite manifested continuous and “sea-island” pore structures with a firm bonding interface between aerogel and RPUF due to the highly reactive activity between biomass chains (amino and hydroxyl groups) and isocyanate. Benefitting from the intricate thermal conductive paths and enhanced interface resistance, introducing aerogel particles can reduce the thermal conductivity from 36.5 mW·m−1·K−1 (RPUF) to 28.6 mW·m−1·K−1, dropped by 21.6 %. Moreover, the aerogel/RPUF composite manifested excellent flame retardancy with a limiting oxygen index of 28 %, a significantly reduced peak heat release rate (−38.0 %) and smoke production (−54.0 %), as well as enhanced compressive strength (+93.7 %). This work provided new insight into fabricating RPUF composites with integrated advantages of high flame-retardant efficiency and outstanding thermal insulation.