Part 1 of this series showed that the purification level and surfactant loadings of organoclays significantly affect their thermal stability; the higher rate of degradation of as-received commercial organoclay is primarily a result of excess surfactant that is intentionally or unintentionally part of the commercial organoclay. Polypropylene nanocomposites and nylon 6 nanocomposites were formed through melt processing to assess the practical consequences, in terms of nanocomposite formation and performance, of using a purified version of the organoclay with no excess surfactant and a lower rate of thermal degradation versus using the as-received organoclay. The properties and morphology of polymer-clay nanocomposites based on both as-received and purified organoclays were evaluated by TEM, WAXS, and mechanical testing. The results from the different techniques were generally consistent with each other suggesting that the differences in thermal stability of organoclays do not appear to have a significant effect on the morphology and properties of the nanocomposites formed from them. (c) 2008 Elsevier Ltd. All rights reserved.