{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/106108"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/106108","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Crystallization kinetics of polylactide and its blends","abstract":"The purpose of this research was first, to investigate a polymerization method to produce polylactides of desired molecular weights. The polymers PLA-L and PLA-DL produced were then utilized to make blends of semicrystalline/amorphous components. The compatibility of the blends was investigated by determining their Tg with a DSC. However, because of the proximity of the Tg's of the two components, a new approach , which utilized the effects of the \"physical\" aging on the the Tg peaks obtained by DSC was considered. The results obtained by this method showed that only three blends containing low molecular weight species were compatible. All the others, while incompatible, possessed a certain degree of partial miscibility. The crystallization kinetics were investigated on the pure PLA-L and the blends. Two separate studies were conducted, the first on the kinetics of the overall crystallization by means of an Avrami analysis, the second on the growth rates of the individual spherulites. The kinetics of crystallization were found to decrease as the molecular weight of the semicrystalline component increased and as the PLA-DL content in the blend increased. In some particular cases, however, a spectacular increase of the growth rates was observed for high DL content blends. Optical microscopy showed that under these conditions, the spherulites grown, contained large inclusions of amorphous material.","abstract_html":"The purpose of this research was first, to investigate a polymerization method to produce polylactides of desired molecular weights. The polymers PLA-L and PLA-DL produced were then utilized to make blends of semicrystalline/amorphous components. The compatibility of the blends was investigated by determining their Tg with a DSC. However, because of the proximity of the Tg's of the two components, a new approach , which utilized the effects of the "physical" aging on the the Tg peaks obtained by DSC was considered. The results obtained by this method showed that only three blends containing low molecular weight species were compatible. All the others, while incompatible, possessed a certain degree of partial miscibility. The crystallization kinetics were investigated on the pure PLA-L and the blends. Two separate studies were conducted, the first on the kinetics of the overall crystallization by means of an Avrami analysis, the second on the growth rates of the individual spherulites. The kinetics of crystallization were found to decrease as the molecular weight of the semicrystalline component increased and as the PLA-DL content in the blend increased. In some particular cases, however, a spectacular increase of the growth rates was observed for high DL content blends. Optical microscopy showed that under these conditions, the spherulites grown, contained large inclusions of amorphous material.","abstract_has_math":false,"creators":["Jorda, Rafael"],"institution":"Virginia Polytechnic Institute and State University","degree_name":"M.S.","degree_level":"masters","degree_discipline":"Chemical Engineering","degree_department":"Chemical Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1986,"date_issued":"1986","date_published":"1986","updated_at":"2026-07-22T22:19:00Z","subjects":[],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10919/106108","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Chemical Engineering"]},{"key":"dc:creator","label":"Author","values":["Jorda, Rafael"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2021-10-26T20:10:09Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2021-10-26T20:10:09Z"]},{"key":"dc:date.issued","label":"Date","values":["1986"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Polytechnic Institute and State University"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]},{"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":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"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.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/106108"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The purpose of this research was first, to investigate a polymerization method to produce polylactides of desired molecular weights. The polymers PLA-L and PLA-DL produced were then utilized to make blends of semicrystalline/amorphous components. The compatibility of the blends was investigated by determining their Tg with a DSC. However, because of the proximity of the Tg's of the two components, a new approach , which utilized the effects of the \"physical\" aging on the the Tg peaks obtained by DSC was considered. The results obtained by this method showed that only three blends containing low molecular weight species were compatible. All the others, while incompatible, possessed a certain degree of partial miscibility. The crystallization kinetics were investigated on the pure PLA-L and the blends. Two separate studies were conducted, the first on the kinetics of the overall crystallization by means of an Avrami analysis, the second on the growth rates of the individual spherulites. The kinetics of crystallization were found to decrease as the molecular weight of the semicrystalline component increased and as the PLA-DL content in the blend increased. In some particular cases, however, a spectacular increase of the growth rates was observed for high DL content blends. Optical microscopy showed that under these conditions, the spherulites grown, contained large inclusions of amorphous material."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["M.S."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Crystallization kinetics of polylactide and its blends"]}]}],"canonical_facts":{"dc:contributor.department":["Chemical Engineering"],"dc:creator":["Jorda, Rafael"],"dc:date.accessioned":["2021-10-26T20:10:09Z"],"dc:date.available":["2021-10-26T20:10:09Z"],"dc:date.issued":["1986"],"dc:description.abstract":["The purpose of this research was first, to investigate a polymerization method to produce polylactides of desired molecular weights. The polymers PLA-L and PLA-DL produced were then utilized to make blends of semicrystalline/amorphous components. The compatibility of the blends was investigated by determining their Tg with a DSC. However, because of the proximity of the Tg's of the two components, a new approach , which utilized the effects of the \"physical\" aging on the the Tg peaks obtained by DSC was considered. The results obtained by this method showed that only three blends containing low molecular weight species were compatible. All the others, while incompatible, possessed a certain degree of partial miscibility. The crystallization kinetics were investigated on the pure PLA-L and the blends. Two separate studies were conducted, the first on the kinetics of the overall crystallization by means of an Avrami analysis, the second on the growth rates of the individual spherulites. The kinetics of crystallization were found to decrease as the molecular weight of the semicrystalline component increased and as the PLA-DL content in the blend increased. In some particular cases, however, a spectacular increase of the growth rates was observed for high DL content blends. Optical microscopy showed that under these conditions, the spherulites grown, contained large inclusions of amorphous material."],"dc:description.degree":["M.S."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/10919/106108"],"dc:language.iso":["en"],"dc:publisher":["Virginia Polytechnic Institute and State University"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Crystallization kinetics of polylactide and its blends"],"dc:type":["Thesis"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Chemical Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["M.S."],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:00Z"}