No abstract

This article addresses the optimization of water‐blown rigid polyurethane (RPU) foams obtained from a polyol functionalized with graphene oxide (GO). For this purpose, a series of RPU foams are herein synthesized by varying either the isocyanate index, the contents of catalyst or the contents of surfactant, or a combination of these three components. The modifications introduced in the formulation are based on the effect of GO on the reaction kinetics. These strategies are mainly focused on the increase of both isocyanate conversion and polymerization reaction, which decrease for the foams containing GO. Density, cellular structure, thermal conductivity, and mechanical properties of the resulting foams are herein investigated. The results show how controlling PU formulation allows to improve both the thermal and the mechanical behavior in these RPU foams containing GO. The highest cell size reduction of 25% and the lowest thermal conductivity are obtained for the sample with a simultaneous increase in isocyanate index, catalyst content, and surfactant content. Moreover, the adequate combination of these components leads to a high improvement of 59% of the relative Young's modulus and of 54% of the relative collapse stress. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47474.

Polyols blends functionalized with graphene oxide (GO-f) and filled with graphene oxide particles (GO-d) are employed to produce rigid PU foams.The foaming behaviour of rigid polyurethane (RPU) foams with GO-f or GO-d is followed by X-Ray radioscopy.The cellular structure of RPU foams such as cell nucleation density and cell size are improved by incorporation of GO-f. GO-f offers better results than GO-d in improving the cellular structure and in providing a more reproducible process.