Polyurethane Adhesive Nanocomposites as Gas Permeation Barrier

作者：Maged A. Osman, Vikas Mittal, Massimo Morbidelli, Ulrich W. Suter · 发表于：Macromolecules · 年份：2003 · DOI：10.1021/ma035077x · 被引用次数：300 · 研究领域：Polymer Nanocomposites and Properties、High voltage insulation and dielectric phenomena、Silicone and Siloxane Chemistry

Adhesive nanocomposites of organically modified montmorillonite (OM) and polyurethane have been synthesized and their permeability to oxygen and water vapor has been measured. The gas permeation through the composites was correlated to the volume fraction of the impermeable inorganic part of the OM. The incorporation of small volume fractions of the platelike nanoparticles in the polymer matrix decreased the gas transmission rate, when the interface between the two heterogeneous phases was properly designed. The oxygen transmission rate decayed asymptotically with increasing aluminosilicate volume fraction and a 30% reduction was achieved at 3 vol %, when the clay was coated with bis(2-hydroxyethyl) hydrogenated tallow ammonium or alkylbenzyldimethylammonium ions. In contrast, coating the clay surface with dimethyl dihydrogenated tallow ammonium ions leads to an increase in the gas transmission rate with augmenting inorganic fraction. This was attributed to a probable change in morphology resulting from phase separation at the interface between the apolar pure hydrocarbon clay coating and the relatively polar PU. The water vapor permeation through the PU nanocomposites was more strongly reduced than oxygen and a 50% reduction was observed at 3 vol % silicate fraction. This was attributed to stronger interactions and hydrogen bonding of the water molecules with the PU matrix as well as to their clustering. Differences in the hydrophobicity of the clay coating influenced the wa...