Polyurethane nanocomposites permeability

Technology for preparing nanocomposites directly via compounding has been investigated by Vaia, Ishii, and Giannelis. Industrial R D efforts have focused on process technology (e.g., melt or monomer exfoliation processes), as there are a number of polymers (e.g., polyolefins) that do not lend themselves to a monomer process. Nanocomposites with a variety of polymers, including polyacrylates or methacrylates, polystyrene, styrene-butadiene rubber, epoxy, polyester, and polyurethane, are amenable to the monomer process. The enhancement of mechanical properties, gas permeability resistance, and heat endurance are the primary objectives for the application of PCN, and their success will establish PCNs as a major commercial product. 

Other potential applications of PNCs include layered clays in elastomers for asphalt modification [263] and for tire applications (low air permeability) [264], and layered clay nanocomposites with epoxy [265], unsaturated polyesters [266], vinyl esters [267], and polyurethanes [268] for coatings and composites. 

Recent publications describe the effects of silica on the conductivity and mechanical properties of a polyethylene oxide/ammonium bifluoride complex containing propylene carbonate [36], as a foam stabilizer in polyester polyurethane foams, and on the properties of polylactic acid nanocomposites prepared by the sol-gel technique [37] (see also Chapter 24), on the mechanical properties and permeability of i-PP composites [38], on the surface hardness of polymers for biomedical devices [39], on enhanced properties of polymer interlayers that are used in multiple layer glazing panels [40]. 

Chang J-H, An YU (2002) Nanocomposites of polyurethane with various organoclays thermomechanical properties, morphology, and gas permeability. J Polym Sci, Part B Polym Phys 40(7) 670-677... 

Adhesive nanocomposites of polyurethane and montmorillonite modified with different organic residues have been synthesized and their permeability to oxygen and water vapour has been measured by Osman et al. The oxygen transmission rate asymptotically decayed with increasing aluminosilicate volume fraction and a 30% reduction was achieved at 3 vol.%, when the elay... 

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