The effects of high-speed processing with multi-screw extruders on clay-based nanocomposites have been investigated in this dissertation. The research builds on previous experiments performed by others in the field of interest. The trials performed in this dissertation included one neat/unfilled formulation and two nanocomposite formulations processed at various speeds up to 3,000 rpm on two different extruders. The base matrix material utilized was an ethylene vinyl acetate copolymer (EVA) with a vinyl acetate level of nine percent, in combination with the two organically modified clays, Cloisite® 20A and Perkalite F100S. The unfilled trials utilized the same base polymer as the nanocomposite formulations.
The two extruders consisted of a high-speed twin screw extruder and a high-speed quad screw extruder. The trials were carried out using different extruder speeds ranging from 150 rpm to 3,000 rpm, to simulate traditional processing speeds and high processing speeds. The formulations were processed in a single operation, where the final product, a film approximately 50 mm wide and 1 mm thick, was shaped and cooled directly from the extruders via a custom film die and laboratory chill roll.
Testing was conducted to ensure the films were composed of the intended ratio of materials via thermogravimetric analysis (TGA), with additional testing looking at nanocomposite properties, such as oxygen permeation rate (OPR), tensile properties, crystallinity via differential scanning calorimetry (DSC), and clay layer spacing via x-ray diffraction (XRD).
The results from the analyzed samples indicated that the Cloisite® 20A nanocomposites were not substantially affected by high speed processing while the Perkalite F100S nanocomposites possibly degraded while at the same time showing an increase in interlayer spacing. The observed outcomes suggest improved intercalation/exfoliation can be achieved during high speed processing given the right combination of composition and process parameters.
|Commitee:||Driscoll, Stephen B, Nagarajan, Ramaswamy, Barry, Carol F|
|School:||University of Massachusetts Lowell|
|School Location:||United States -- Massachusetts|
|Source:||DAI-B 81/12(E), Dissertation Abstracts International|
|Subjects:||Plastics, Nanoscience, Nanotechnology|
|Keywords:||EVA, Exfoliation, High speed extrusion, Nanoclay, Nanocomposite, Organoclay|
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