| Abstract
| - The supercritical carbon dioxide induced swelling and plasticization of polyamide 11 wereinvestigated. The swelling kinetics exhibit an initial region of large swelling, in which thediffusion of CO2 into the polymer follows Fickian behavior, and a subsequent region of smallvolume increase that asymptotically approaches an equilibrium swelling value. The diffusioncoefficient of CO2 in polyamide 11 was calculated from the initial slope of the swelling kineticsdata. CO2, injected up to 3 wt % using an extrusion rheometer, is shown to be an effectiveplasticizer for polyamide 11, lowering the viscosity of the polymer melt by as much as 50%. Theuse of CO2 as a blowing agent was also investigated, and we report preliminary foaming attemptsusing a batch process. We obtained homogeneously distributed foams, featuring well-definedclosed cells with an average diameter of 30 μm that had an unfoamed skin layer.
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