Synthesis and characterization of silica aerogel reinforced rigid polyurethane foam for thermal insulation application

This study reports the synthesis of silica aerogel/rigid polyurethane foam nanocomposite with efficient thermal insulation properties. Nanocomposite were prepared in two different states: 1. Adding silica aerogel to MDI matrix, and 2. Adding silica aerogel to polyol matrix by using of various weight percentages of silica aerogel (1-5 wt.%). Many techniques were used in order to investigate the effects of silica aerogel on the mechanical, structural, hydrophobic and thermal properties of the nanocomposites. FTIR observations confirmed the reaction between the silica aerogel and MDI matrix, while no reaction was observed between the silica aerogel and polyol matrix. The datum of thermal conductivity and water-contact angle analyses showed that by increasing the silica aerogel content from 0 to 5 wt.%, the thermal conductivity of the cyclopentane blown foams were lowered from 0.0314 to 0.0268 W/(m K) and hydrophobicity values were increased up to about 24.14% (from 72.13° to 89.57°). However, from the results of mechanical properties, it was concluded that when the silica aerogel content reached 3 wt.%, the module and yield stress of foams were enhanced by 18.63% and 13.83%, respectively and then, they were declined by increasing the silica aerogel content. The cell morphology also revealed the same trend.