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Effects of TiO 2 , ZnO, and Fe 3 O 4 nanofillers on rheological behavior, microstructure, and reaction kinetics of rigid polyurethane foams
Author(s) -
Akkoyun Meral,
Suvaci Ender
Publication year - 2016
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.43658
Subject(s) - materials science , polyurethane , microstructure , nucleation , rheology , chemical engineering , composite material , polyol , coalescence (physics) , exothermic reaction , kinetics , polymerization , polymer , chemistry , organic chemistry , engineering , physics , quantum mechanics , astrobiology
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 (≈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 (≈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. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43658.