{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/22099"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/22099","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Oriented polymer crystal growth from flowing solutions","abstract":"The kinetics of dilute solution flow-induced crystallization in a tubular flow geometry have been quantified for several polymer systems using digital image processing to observe and monitor the birefringence of the crystallizing fiber. Three molecular weights of polyethylene were studied in 0.01 wt% xylene solutions as well as solutions of polypropylene in decalin and solutions of polystyrene in xylene. Crystallization was studied over a range of temperatures and flowrates and was found to always occur by a two-step process with a highly concentrated amorphous polymer phase forming first, followed later by crystallization. The kinetics were observed to follow the Avrami equation. The time exponent, n, was found to have values around 2, while the constant, k/X$\\sb\\infty$, was found to show the predicted temperature dependency for nucleation and growth kinetics, i.e. proportionality to exp($-$T$\\sb\\infty$/T$\\sb{\\rm x}\\Delta$T). It was found that the melting point elevation predicted from theories of strain-induced crystallization could not be used to explain the rapid kinetics of crystallization. Consequently, a theory was developed which allowed the observed solution velocity effects to be included into the Avrami equation thereby yielding a quantitative explanation for the role of flow in the crystal nucleation and growth process. Work with amorphous polystyrene showed the initial unoriented phase separation step occurring, although the phase appeared to be a swollen gel. Further work on the precursor and its formation is crucial to advancing knowledge in this area.","abstract_html":"The kinetics of dilute solution flow-induced crystallization in a tubular flow geometry have been quantified for several polymer systems using digital image processing to observe and monitor the birefringence of the crystallizing fiber. Three molecular weights of polyethylene were studied in 0.01 wt% xylene solutions as well as solutions of polypropylene in decalin and solutions of polystyrene in xylene. Crystallization was studied over a range of temperatures and flowrates and was found to always occur by a two-step process with a highly concentrated amorphous polymer phase forming first, followed later by crystallization. The kinetics were observed to follow the Avrami equation. The time exponent, n, was found to have values around 2, while the constant, k/X$\\sb\\infty$, was found to show the predicted temperature dependency for nucleation and growth kinetics, i.e. proportionality to exp($-$T$\\sb\\infty$/T$\\sb{\\rm x}\\Delta$T). It was found that the melting point elevation predicted from theories of strain-induced crystallization could not be used to explain the rapid kinetics of crystallization. Consequently, a theory was developed which allowed the observed solution velocity effects to be included into the Avrami equation thereby yielding a quantitative explanation for the role of flow in the crystal nucleation and growth process. Work with amorphous polystyrene showed the initial unoriented phase separation step occurring, although the phase appeared to be a swollen gel. Further work on the precursor and its formation is crucial to advancing knowledge in this area.","abstract_has_math":true,"creators":["Spevacek, John Anthony"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Chemical Engineering","degree_department":null,"school":null,"contributors":["McHugh, Anthony J."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T13:28:55Z","date_published":"2011-05-07T13:28:55Z","updated_at":"2026-07-22T22:25:19Z","subjects":["Chemistry, Polymer","Engineering, Materials Science"],"languages":["eng"],"rights":["Copyright 1990 Spevacek, John Anthony"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9021759","(UMI)AAI9021759"],"render_values":[{"text":"AAI9021759","href":null,"code":true},{"text":"(UMI)AAI9021759","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/22099","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["McHugh, Anthony J."]},{"key":"dc:creator","label":"Author","values":["Spevacek, John Anthony"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T13:28:55Z","10000-01-01","1990"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chemistry, Polymer","Engineering, Materials Science"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1990 Spevacek, John Anthony"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9021759","(UMI)AAI9021759","http://hdl.handle.net/2142/22099"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The kinetics of dilute solution flow-induced crystallization in a tubular flow geometry have been quantified for several polymer systems using digital image processing to observe and monitor the birefringence of the crystallizing fiber. Three molecular weights of polyethylene were studied in 0.01 wt% xylene solutions as well as solutions of polypropylene in decalin and solutions of polystyrene in xylene. Crystallization was studied over a range of temperatures and flowrates and was found to always occur by a two-step process with a highly concentrated amorphous polymer phase forming first, followed later by crystallization. The kinetics were observed to follow the Avrami equation. The time exponent, n, was found to have values around 2, while the constant, k/X$\\sb\\infty$, was found to show the predicted temperature dependency for nucleation and growth kinetics, i.e. proportionality to exp($-$T$\\sb\\infty$/T$\\sb{\\rm x}\\Delta$T). It was found that the melting point elevation predicted from theories of strain-induced crystallization could not be used to explain the rapid kinetics of crystallization. Consequently, a theory was developed which allowed the observed solution velocity effects to be included into the Avrami equation thereby yielding a quantitative explanation for the role of flow in the crystal nucleation and growth process. Work with amorphous polystyrene showed the initial unoriented phase separation step occurring, although the phase appeared to be a swollen gel. Further work on the precursor and its formation is crucial to advancing knowledge in this area.","Made available in DSpace on 2011-05-07T13:28:55Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9021759.pdf: 3883145 bytes, checksum: 6837d7b878e975515502d1378e7a30b3 (MD5) Previous issue date: 1990","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:55:19Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:25:46-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Oriented polymer crystal growth from flowing solutions"]}]}],"canonical_facts":{"dc:contributor":["McHugh, Anthony J."],"dc:creator":["Spevacek, John Anthony"],"dc:date":["2011-05-07T13:28:55Z","10000-01-01","1990"],"dc:description":["The kinetics of dilute solution flow-induced crystallization in a tubular flow geometry have been quantified for several polymer systems using digital image processing to observe and monitor the birefringence of the crystallizing fiber. Three molecular weights of polyethylene were studied in 0.01 wt% xylene solutions as well as solutions of polypropylene in decalin and solutions of polystyrene in xylene. Crystallization was studied over a range of temperatures and flowrates and was found to always occur by a two-step process with a highly concentrated amorphous polymer phase forming first, followed later by crystallization. The kinetics were observed to follow the Avrami equation. The time exponent, n, was found to have values around 2, while the constant, k/X$\\sb\\infty$, was found to show the predicted temperature dependency for nucleation and growth kinetics, i.e. proportionality to exp($-$T$\\sb\\infty$/T$\\sb{\\rm x}\\Delta$T). It was found that the melting point elevation predicted from theories of strain-induced crystallization could not be used to explain the rapid kinetics of crystallization. Consequently, a theory was developed which allowed the observed solution velocity effects to be included into the Avrami equation thereby yielding a quantitative explanation for the role of flow in the crystal nucleation and growth process. Work with amorphous polystyrene showed the initial unoriented phase separation step occurring, although the phase appeared to be a swollen gel. Further work on the precursor and its formation is crucial to advancing knowledge in this area.","Made available in DSpace on 2011-05-07T13:28:55Z (GMT). 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