Please use this identifier to cite or link to this item:
http://hdl.handle.net/11375/11288
Title: | Influence of Additives on the Foamability of Potato Starch based Biopolymers |
Authors: | Oza, Hiteshkumar G. |
Advisor: | Thompson, Michael Hrymak, Andrew Hoare, Todd |
Department: | Chemical Engineering |
Keywords: | Hydrolyzed Starch;Poly (lactic acid);Chian Extender. Batch Foaming;Polymer Science;Polymer Science |
Publication Date: | Oct-2011 |
Abstract: | <p>In this study, attempts were made to diversify the application of potato starch based biopolymer as foam-grade materials. To improve foamability, which is largely dependent on melt strength, it is possible to modify hydrolyzed starch based biopolymers by bulk modification with bi- and multi- functional epoxy chain extenders. The modification work was carried out using a twin screw extruder (TSE) and an internal batch mixer (Haake Mixer) with four different chain extenders. The modified blends were characterized by Parallel Plate Rheometry, DSC, Intrinsic Viscosity and SEM techniques. Finally, foamability of the modified blends was examined by using supercritical CO<sub>2</sub> as a physical blowing agent in a high-pressure batch vessel. Variables such as saturation pressure, saturation time and saturation temperature were adjusted to determine their influence on the cell morphology of the foamed parts.</p> <p>The multi-functional epoxy chain extenders effectively increased the bulk melt viscosity and reduced the crystalline content of both hydrolyzed starch based biopolymers. The intrinsic viscosity measurements were quantified the chain extension reaction, which primarily occurred in the PLA/AAC or PLA phase in both biopolymers and the starch phase made no contribution towards increased bulk melt viscosity. The multi-functional Joncryl<sup>®</sup> ADR 4370S was the most effective chain extender for improving the stability of foams by yielding smaller cell size and higher cell density in comparison with the original biopolymer during the batch foaming process at 10 MPa saturation pressure and 30 min saturation time. The use of other chain extenders proved to be mostly ineffectual in producing uniform cellular structure in their corresponding modified biopolymer at those same processing conditions.</p> |
URI: | http://hdl.handle.net/11375/11288 |
Identifier: | opendissertations/6268 7311 2259378 |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
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fulltext.pdf | 5.17 MB | Adobe PDF | View/Open |
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