{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/32187"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/32187","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Improving the Exfoliation of Layered Silicate in a Poly(ethylene terephthalate) Matrix Using Supercritical Carbon Dioxide","abstract":"Supercritical carbon dioxide (scCO2) was used as a processing aid to improve the level of exfoliation achievable in a PET-layered silicate nanocomposite produced from melt compounding. Layered silicate and scCO2 were allowed to mix for a period of time before being released into the second stage of a single screw extruder. The rapid expansion forced silicate particles into a modified hopper containing neat PET pellets. The mixture of layered silicate and PET was immediately melt mixed in a single screw extruder, cooled in a water bath and pelletized. Two sets of samples each containing layered silicate with different surface chemistries were produced with this method at 1, 3 and 5 wt% silicate. For comparison, samples of the same weight fraction and type of silicate were produced from a traditional melt compounding method. Wide angle x-ray diffraction (WAXD), mechanical testing and rheological analysis were used in order to characterize the silicate morphology, the composite mechanical properties and the relative amount of degradation between the various samples. Results show that scCO2 processed samples contain a higher degree of layered silicate exfoliation than samples produced with traditional melt compounding. Mechanical property improvements are shown to be dependent on the type of silicate surface modification employed. Finally, degradation of the PET matrix appears to be far less extensive in the scCO2 processed samples as shown from rheological data.","abstract_html":"Supercritical carbon dioxide (scCO2) was used as a processing aid to improve the level of exfoliation achievable in a PET-layered silicate nanocomposite produced from melt compounding. Layered silicate and scCO2 were allowed to mix for a period of time before being released into the second stage of a single screw extruder. The rapid expansion forced silicate particles into a modified hopper containing neat PET pellets. The mixture of layered silicate and PET was immediately melt mixed in a single screw extruder, cooled in a water bath and pelletized. Two sets of samples each containing layered silicate with different surface chemistries were produced with this method at 1, 3 and 5 wt% silicate. For comparison, samples of the same weight fraction and type of silicate were produced from a traditional melt compounding method. Wide angle x-ray diffraction (WAXD), mechanical testing and rheological analysis were used in order to characterize the silicate morphology, the composite mechanical properties and the relative amount of degradation between the various samples. Results show that scCO2 processed samples contain a higher degree of layered silicate exfoliation than samples produced with traditional melt compounding. Mechanical property improvements are shown to be dependent on the type of silicate surface modification employed. Finally, degradation of the PET matrix appears to be far less extensive in the scCO2 processed samples as shown from rheological data.","abstract_has_math":false,"creators":["Samaniuk, Joseph Reese"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Chemical Engineering","degree_department":"Chemical Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Baird, Donald G."],"committee_members":["Walz, John Y.","Davis, Richey M."],"year":2008,"date_issued":"2008-04-29","date_published":"2008-04-29","updated_at":"2026-07-22T22:19:00Z","subjects":["PLSN","polymer-layered silicate nanocomposite","poly(ethylene terephthalate)","supercritical carbon dioxide","nanoclay"],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-05042008-010025"],"render_values":[{"text":"etd-05042008-010025","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/32187","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Baird, Donald G."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Walz, John Y.","Davis, Richey M."]},{"key":"dc:contributor.department","label":"Department","values":["Chemical Engineering"]},{"key":"dc:creator","label":"Author","values":["Samaniuk, Joseph Reese"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:35:00Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:35:00Z","2008-05-27"]},{"key":"dc:date.issued","label":"Date","values":["2008-04-29"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["PLSN","polymer-layered silicate nanocomposite","poly(ethylene terephthalate)","supercritical carbon dioxide","nanoclay"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-05042008-010025"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/32187"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Supercritical carbon dioxide (scCO2) was used as a processing aid to improve the level of exfoliation achievable in a PET-layered silicate nanocomposite produced from melt compounding. Layered silicate and scCO2 were allowed to mix for a period of time before being released into the second stage of a single screw extruder. The rapid expansion forced silicate particles into a modified hopper containing neat PET pellets. The mixture of layered silicate and PET was immediately melt mixed in a single screw extruder, cooled in a water bath and pelletized. Two sets of samples each containing layered silicate with different surface chemistries were produced with this method at 1, 3 and 5 wt% silicate. For comparison, samples of the same weight fraction and type of silicate were produced from a traditional melt compounding method. Wide angle x-ray diffraction (WAXD), mechanical testing and rheological analysis were used in order to characterize the silicate morphology, the composite mechanical properties and the relative amount of degradation between the various samples. Results show that scCO2 processed samples contain a higher degree of layered silicate exfoliation than samples produced with traditional melt compounding. Mechanical property improvements are shown to be dependent on the type of silicate surface modification employed. Finally, degradation of the PET matrix appears to be far less extensive in the scCO2 processed samples as shown from rheological data."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["Improving the Exfoliation of Layered Silicate in a Poly(ethylene terephthalate) Matrix Using Supercritical Carbon Dioxide"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Baird, Donald G."],"dc:contributor.committeemember":["Walz, John Y.","Davis, Richey M."],"dc:contributor.department":["Chemical Engineering"],"dc:creator":["Samaniuk, Joseph Reese"],"dc:date.accessioned":["2014-03-14T20:35:00Z"],"dc:date.available":["2014-03-14T20:35:00Z","2008-05-27"],"dc:date.issued":["2008-04-29"],"dc:description.abstract":["Supercritical carbon dioxide (scCO2) was used as a processing aid to improve the level of exfoliation achievable in a PET-layered silicate nanocomposite produced from melt compounding. Layered silicate and scCO2 were allowed to mix for a period of time before being released into the second stage of a single screw extruder. The rapid expansion forced silicate particles into a modified hopper containing neat PET pellets. The mixture of layered silicate and PET was immediately melt mixed in a single screw extruder, cooled in a water bath and pelletized. Two sets of samples each containing layered silicate with different surface chemistries were produced with this method at 1, 3 and 5 wt% silicate. For comparison, samples of the same weight fraction and type of silicate were produced from a traditional melt compounding method. Wide angle x-ray diffraction (WAXD), mechanical testing and rheological analysis were used in order to characterize the silicate morphology, the composite mechanical properties and the relative amount of degradation between the various samples. Results show that scCO2 processed samples contain a higher degree of layered silicate exfoliation than samples produced with traditional melt compounding. Mechanical property improvements are shown to be dependent on the type of silicate surface modification employed. Finally, degradation of the PET matrix appears to be far less extensive in the scCO2 processed samples as shown from rheological data."],"dc:description.degree":["Master of Science"],"dc:identifier.other":["etd-05042008-010025"],"dc:identifier.uri":["http://hdl.handle.net/10919/32187"],"dc:language.iso":["en"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["PLSN","polymer-layered silicate nanocomposite","poly(ethylene terephthalate)","supercritical carbon dioxide","nanoclay"],"dc:title":["Improving the Exfoliation of Layered Silicate in a Poly(ethylene terephthalate) Matrix Using Supercritical Carbon Dioxide"],"dc:type":["Thesis"],"thesis:degree_discipline":["Chemical Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:00Z"}