Effects Of Tio2, Zno, And Fe3O4 Nanofillers On Rheological Behavior, Microstructure, And Reaction Kinetics Of Rigid Polyurethane Foams

WOS: 000374774100012
Effects of different types and shapes of titanium dioxide, zinc oxide, and magnetite nanofillers on the rheological behavior of polyol/nanofiller suspensions, on the rigid polyurethane foam formation reaction, and hence on the final microstructure were investigated. The rheological percolation threshold of polyol/nanofiller suspensions decreased as the aspect ratio of nonspherical nanoparticles (platelet or rod) increased, regardless of the nanofiller type. The results of reaction kinetics showed that above a critical surface area (approximate to 30 m(2)), independently of nanofiller type, the reaction rate increased as the surface area increased. The introduction of oxide surfaces reduced the final cell size until a critical surface area (approximate to 30 m(2)). However, above this critical value cell size distribution gets wider and the cell size can no longer be correlated with the surface area. In the latter case, an increase of the reaction rate and the polymerization reaction being exothermic may facilitate uncontrolled cell nucleation, growth, and hence coalescence which results in an uncontrolled foam structure
Scientific and Technological Research Council of Turkey (TUBITAK); Scientific Projects Commission of Anadolu University [1404F169]
Burcu Ceren Dabak is acknowledged for the production of TiO2 nanorods and ZnO nanoplatelets used in this study. The Scientific and Technological Research Council of Turkey (TUBITAK) and the Scientific Projects Commission of Anadolu University (under the contract number of 1404F169) are also gratefully acknowledged for their financial support.