Synthesis and Properties of Vermiculite-Reinforced Polyurethane Nanocomposites

• Published in: ACS applied materials & interfaces 2011-09, Vol.3 (9), p.3709-3717
• Main Authors: Qian, Yuqiang, Lindsay, Chris I, Macosko, Chris, Stein, Andreas
• Format: Article
• Language: English
• Subjects: Aluminum Silicates - chemistry; Calorimetry, Differential Scanning; Epoxy Compounds - chemistry; Ethylene Oxide - chemistry; Nanocomposites - chemistry; Nitrogen - chemistry; Polymers - chemistry; Polyurethanes - chemistry; Quaternary Ammonium Compounds - chemistry
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/am2008954

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 N2 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.