title: Synthesis and properties of vermiculite-reinforced polyurethane nanocomposites.
abstract: Natural vermiculite was modified by cation exchange with long-chain quaternary alkylammonium salts and then dispersed in polyether-based polyols with different structures and ethylene oxide/propylene oxide ratios. The dispersions were evaluated by X-ray scattering and rheology. In all polyol dispersions tested, polyols were intercalated into the vermiculite interlayers. Also, significant shear thinning behavior was observed. A large interlayer spacing of ∼90 Å was achieved in one polyol suitable for polyurethane elastomer synthesis. In polyurethane made with this polyol, clay platelets were extensively intercalated or exfoliated. The composites showed a >270% increase in tensile modulus, >60% increase in tensile strength, and a 30% reduction in N(2) permeability with a loading of 5.3 wt % clay in polyurethane. Differential scanning calorimetry and dynamic mechanical analysis revealed that the nanoclay interacts with the polyurethane hard segments.
authors.affiliation: Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States.
authors.forename: Yuqiang
authors.initials: Y
authors.lastname: Qian
authors.forename: Chris I
authors.initials: CI
authors.lastname: Lindsay
authors.forename: Chris
authors.initials: C
authors.lastname: Macosko
authors.forename: Andreas
authors.initials: A
authors.lastname: Stein
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D004852:Epoxy Compounds / Q000737:chemistry; D005027:Ethylene Oxide / Q000737:chemistry; D053761:Nanocomposites / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D004852:Epoxy Compounds; D011108:Polymers; D011140:Polyurethanes; D000644:Quaternary Ammonium Compounds; C024617:polyol; C003760:vermiculite; D005027:Ethylene Oxide; D009584:Nitrogen; C009068:propylene oxide