{"id":{"repo_id":"helsinki","oai_identifier":"oai:helda.helsinki.fi:10138/229530"},"canonical_url":"https://search.dev.ndltd.org/etd/helsinki/oai:helda.helsinki.fi:10138/229530","repository":{"repo_id":"helsinki","name":"University of Helsinki","base_url":"https://helda.helsinki.fi/server/oai/request"},"display":{"title":"Synthesis and characterization of thermo-responsive polyethers","abstract":"Hyaluronic acid (HA) hydrogels are interesting biomaterials for drug delivery and tissue engineering applications. Glycidyl ether derivatives have gained much interests due to their thermo-responsive properties. Thermo-responsive random copolymers of glycidyl methyl ether (GME) and epoxyhexane (EH) were synthesized. Once their properties were studied, they were grafted onto hyaluronic acid to obtain gelation at temperatures above the phase transition temperature of poly (GME-EH). PGME is a water-soluble polymer at low temperatures, but phase separates at 57.3oC. The transition temperature of PGME is too high to be utilized in medical applications. Thus a hydrophobic monomer EH was used to decrease the transition temperature of PGME via copolymerization. Several samples of random copolymers poly (GME-EH) were successfully synthesized by anionic ring opening polymerization (AROP). The transition temperature of copolymers was characterized by NMR, turbidimetry and micro-calorimetry respectively to study the phase transition behavior. Tetraoctylammonium bromide was used as initiator resulting with a bromide as the end group. Bromide was substituted by azide group to be used in click chemistry reaction with alkyne-functional HA. The reaction of the azide group on the end of copolymer chain was detected by FT-IR spectroscopy. Grafting was achieved by click chemistry following copper-catalyzed azide-alkyne cycloaddition (CuAAC) procedure. Rheology was used to study the gelation of the final product: thermo-responsive hyaluronic acid hydrogel. However, for different reasons the final product failed to form a gel.","abstract_html":"Hyaluronic acid (HA) hydrogels are interesting biomaterials for drug delivery and tissue engineering applications. Glycidyl ether derivatives have gained much interests due to their thermo-responsive properties. Thermo-responsive random copolymers of glycidyl methyl ether (GME) and epoxyhexane (EH) were synthesized. Once their properties were studied, they were grafted onto hyaluronic acid to obtain gelation at temperatures above the phase transition temperature of poly (GME-EH). PGME is a water-soluble polymer at low temperatures, but phase separates at 57.3oC. The transition temperature of PGME is too high to be utilized in medical applications. Thus a hydrophobic monomer EH was used to decrease the transition temperature of PGME via copolymerization. Several samples of random copolymers poly (GME-EH) were successfully synthesized by anionic ring opening polymerization (AROP). The transition temperature of copolymers was characterized by NMR, turbidimetry and micro-calorimetry respectively to study the phase transition behavior. Tetraoctylammonium bromide was used as initiator resulting with a bromide as the end group. Bromide was substituted by azide group to be used in click chemistry reaction with alkyne-functional HA. The reaction of the azide group on the end of copolymer chain was detected by FT-IR spectroscopy. Grafting was achieved by click chemistry following copper-catalyzed azide-alkyne cycloaddition (CuAAC) procedure. Rheology was used to study the gelation of the final product: thermo-responsive hyaluronic acid hydrogel. However, for different reasons the final product failed to form a gel.","abstract_has_math":false,"creators":["Xia, Jingwen"],"institution":"Helsingin yliopisto","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Helsingin yliopisto, Matemaattis-luonnontieteellinen tiedekunta, Kemian laitos","University of Helsinki, Faculty of Science, Department of Chemistry","Helsingfors universitet, Matematisk-naturvetenskapliga fakulteten, Kemiska institutionen"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2017,"date_issued":"2017","date_published":"2017","updated_at":"2026-07-27T19:56:27Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["URN:NBN:fi-fe2017121155632"],"render_values":[{"text":"URN:NBN:fi-fe2017121155632","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10138/229530","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Helsingin yliopisto, Matemaattis-luonnontieteellinen tiedekunta, Kemian laitos","University of Helsinki, Faculty of Science, Department of Chemistry","Helsingfors universitet, Matematisk-naturvetenskapliga fakulteten, Kemiska institutionen"]},{"key":"dc:creator","label":"Author","values":["Xia, Jingwen"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2017"]},{"key":"dc:publisher","label":"Institution","values":["Helsingin yliopisto","University of Helsinki","Helsingfors universitet"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["URN:NBN:fi-fe2017121155632","http://hdl.handle.net/10138/229530"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Hyaluronic acid (HA) hydrogels are interesting biomaterials for drug delivery and tissue engineering applications. Glycidyl ether derivatives have gained much interests due to their thermo-responsive properties. Thermo-responsive random copolymers of glycidyl methyl ether (GME) and epoxyhexane (EH) were synthesized. Once their properties were studied, they were grafted onto hyaluronic acid to obtain gelation at temperatures above the phase transition temperature of poly (GME-EH). PGME is a water-soluble polymer at low temperatures, but phase separates at 57.3oC. The transition temperature of PGME is too high to be utilized in medical applications. Thus a hydrophobic monomer EH was used to decrease the transition temperature of PGME via copolymerization. Several samples of random copolymers poly (GME-EH) were successfully synthesized by anionic ring opening polymerization (AROP). The transition temperature of copolymers was characterized by NMR, turbidimetry and micro-calorimetry respectively to study the phase transition behavior. Tetraoctylammonium bromide was used as initiator resulting with a bromide as the end group. Bromide was substituted by azide group to be used in click chemistry reaction with alkyne-functional HA. The reaction of the azide group on the end of copolymer chain was detected by FT-IR spectroscopy. Grafting was achieved by click chemistry following copper-catalyzed azide-alkyne cycloaddition (CuAAC) procedure. Rheology was used to study the gelation of the final product: thermo-responsive hyaluronic acid hydrogel. However, for different reasons the final product failed to form a gel."]},{"key":"dc:title","label":"Title","values":["Synthesis and characterization of thermo-responsive polyethers"]}]}],"canonical_facts":{"dc:contributor":["Helsingin yliopisto, Matemaattis-luonnontieteellinen tiedekunta, Kemian laitos","University of Helsinki, Faculty of Science, Department of Chemistry","Helsingfors universitet, Matematisk-naturvetenskapliga fakulteten, Kemiska institutionen"],"dc:creator":["Xia, Jingwen"],"dc:date.issued":["2017"],"dc:description.abstract":["Hyaluronic acid (HA) hydrogels are interesting biomaterials for drug delivery and tissue engineering applications. Glycidyl ether derivatives have gained much interests due to their thermo-responsive properties. Thermo-responsive random copolymers of glycidyl methyl ether (GME) and epoxyhexane (EH) were synthesized. Once their properties were studied, they were grafted onto hyaluronic acid to obtain gelation at temperatures above the phase transition temperature of poly (GME-EH). PGME is a water-soluble polymer at low temperatures, but phase separates at 57.3oC. The transition temperature of PGME is too high to be utilized in medical applications. Thus a hydrophobic monomer EH was used to decrease the transition temperature of PGME via copolymerization. Several samples of random copolymers poly (GME-EH) were successfully synthesized by anionic ring opening polymerization (AROP). The transition temperature of copolymers was characterized by NMR, turbidimetry and micro-calorimetry respectively to study the phase transition behavior. Tetraoctylammonium bromide was used as initiator resulting with a bromide as the end group. Bromide was substituted by azide group to be used in click chemistry reaction with alkyne-functional HA. The reaction of the azide group on the end of copolymer chain was detected by FT-IR spectroscopy. Grafting was achieved by click chemistry following copper-catalyzed azide-alkyne cycloaddition (CuAAC) procedure. Rheology was used to study the gelation of the final product: thermo-responsive hyaluronic acid hydrogel. However, for different reasons the final product failed to form a gel."],"dc:identifier.uri":["URN:NBN:fi-fe2017121155632","http://hdl.handle.net/10138/229530"],"dc:language.iso":["eng"],"dc:publisher":["Helsingin yliopisto","University of Helsinki","Helsingfors universitet"],"dc:title":["Synthesis and characterization of thermo-responsive polyethers"]},"updated_at":"2026-07-27T19:56:27Z"}