Reinforcement and environmental degradation of nylon-6/clay nanocomposites

Hybrid organic/inorganic nanocomposites are being developed to improve the physical and mechanical properties of polymeric materials without adversely effecting their processing characteristics. One such nanocomposite developed by Toyota and commercialized by Ube Industries is the nylon-6/montmorillonite clay nanocomposite. The mechanism of reinforcement in nylon-6/clay nanocomposite materials is investigated through tensile experiments, infrared absorption spectrography, and dynamic mechanical analysis. 200% improvements in modulus and 175% improvements in yield stress are attributed to the complexation of mid-chain carbonyl groups with the exfoliated clay lamellae. Because of the initial use of these materials in automotive components, and the known deleterious effects of the air pollutant NOx on nylon-6, the degradation of the nanocomposites in NOx was examined through post-exposure tensile experiments. It was found that NOx degrades the mechanical performance of the nanocomposites regardless of the constraining effect of clay lamellae. (C) 2001 Elsevier Science Ltd. All rights reserved.