RT info:eu-repo/semantics/article T1 Improving the insulating capacity of polyurethane foams through polyurethane aerogel inclusion: From insulation to superinsulation A1 Merillas Valero, Beatriz A1 Villafañe González, Fernando A1 Rodríguez Pérez, Miguel Ángel K1 Polymers K1 Polyurethane foam K1 Espumas poliméricas de poliuretano - Propiedade mecánicas K1 Mechanical properties K1 Composite materials K1 Gels K1 Aerogel K1 Thermal insulation K1 Aislamiento térmico K1 Condensed matter K1 Física de la materia condensada K1 Chemistry K1 23 Química K1 2206.10 Polímeros K1 2211.02 Materiales Compuestos AB A novel synthesis of polyurethane foam/polyurethane aerogel (PUF–PUA) composites is presented. Three different polyurethane reticulated foams which present the same density but different pore sizes (named S for small, M for medium, and L for large) have been used. After the characterization of the reference materials (either, foams, and pure aerogel), the obtained composites have been characterized in order to study the effect of the foam pore size on the final properties, so that density, shrinkage, porous structure, mechanical properties, and thermal conductivity are determined. A clear influence of the pore size on the density and shrinkage was found, and the lowest densities are those obtained from L composites (123 kg/m3). Moreover, the aerogel density and shrinkage have been significantly reduced through the employment of the polyurethane (PU) foam skeleton. Due to the enhanced mechanical properties of polyurethane aerogels, the inclusion of polyurethane aerogel into the foam skeleton helps to increase the elastic modulus of the foams from 0.03 and 0.08 MPa to 0.85 MPa, while keeping great flexibility and recovery ratios. Moreover, the synthesized PUF–PUA composites show an excellent insulating performance, reducing the initial thermal conductivity values from 34.1, 40.3, and 50.6 mW/(m K) at 10 °C for the foams S, M, and L, to 15.8, 16.6, and 16.1 mW/(m K), respectively. Additionally, the effect of the different heat transfer mechanisms to the total thermal conductivity is herein analyzed by using a theoretical model as well as the influence of the measurement temperature. PB MDPI SN 2079-4991 YR 2022 FD 2022 LK https://uvadoc.uva.es/handle/10324/61898 UL https://uvadoc.uva.es/handle/10324/61898 LA eng NO Nanomaterials, 2022, Vol. 12, Nº. 13, 2232 NO Producción Científica DS UVaDOC RD 24-nov-2024