Investigation of novel expandable polystyrene/alumina aerogel composite thermal insulation material

Expandable polystyrene (EPS) foam is one of the most commonly used building thermal insulation materials due to its low thermal conductivity, apparent density as well and low cost. However, its high flammability and the release of a large number of toxic gases during combustion hinder its application. In this paper, using EPS foam and alumina aerogel (Al2O3) as insulation components, epoxy resin (EP) as a binder, and expandable graphite (EG) and ammonium polyphosphate (APP) as composite flame-retardant, a novel organic-inorganic composite thermal insulation material (EPS-AEA) was designed and fabricated. Experiment results showed that adding Al2O3 to EPS could further reduce the thermal conductivity of the obtained composite, and improve its mechanical properties. The addition of EG and APP composite flame-retardant could markedly enhance flame-retardant performance. With the addition of 4.17% Al2O3, and 50% EG/APP (1/1 mass ratio), the obtained EPS-AEA-1/1 composite showed superior fire resistance (reaching UL-94 V-0 rating and limiting oxygen index (LOI of 40.6%), high thermal insulation (thermal conductivity of 0.0487 W/(m·K)and applicable mechanical properties. In addition, EPS-AEA had excellent anti-hygroscopic properties (moisture ab-desorption rate within 0.5%) and fairly low toxic gas emissions during combustion, indicating its potential in practical application.