Influence of (1,3-phenylene)bis(3-methyl-1-phenyl pentylidene)dilithium initiator concentration on the modality of polybutadiene

Handle URI:
http://hdl.handle.net/10754/562422
Title:
Influence of (1,3-phenylene)bis(3-methyl-1-phenyl pentylidene)dilithium initiator concentration on the modality of polybutadiene
Authors:
Vasilakopoulos, Thodoris C.; Hadjichristidis, Nikolaos ( 0000-0003-1442-1714 )
Abstract:
The strong influence of (1,3-phenylene)bis(3-methyl-1-phenyl pentylidene)dilithium initiator (DLI) concentration on the modality of polybutadiene (PBd) in the presence of lithium s-butoxide (s-BuOLi) in benzene, at room temperature, has been studied. The quality of DLI has been evaluated by gas chromatography-mass spectrometry (GC-MS) and 1H NMR. Keeping s-BuOLi/C-Li ratio (R) close to unity, at relatively high DLI concentrations (C > 7 × 10-4 M), monomodal high 1,4-PBds with polydispersity index less than 1.07 were obtained, whereas bimodal ones at lower concentrations (C < 6 × 10-4 M). The effect of C-Li concentration on the modality of PBd has been evaluated using size exclusion chromatography on samples taken during and at the end of the polymerization. Viscosity observations have also been used to further support the results. The bimodality of PBd has been attributed to partially terminated difunctional species because of the inevitable presence of protic impurities in the polymerization solution, although high vacuum technique was used, which becomes more significant at low initiator concentrations. Moreover, the strong influence of s-BuOLi on the microstructure of PBd has been demonstrated by 1H NMR. © 2012 Wiley Periodicals, Inc.
KAUST Department:
KAUST Catalysis Center (KCC); Physical Sciences and Engineering (PSE) Division; Chemical Science Program; Polymer Synthesis Laboratory
Publisher:
Wiley-Blackwell
Journal:
Journal of Polymer Science Part A: Polymer Chemistry
Issue Date:
26-Nov-2012
DOI:
10.1002/pola.26435
Type:
Article
ISSN:
0887624X
Sponsors:
The authors thank J. Roovers for the invaluable suggestions and comments. Stavroula Batistatou, University of Athens, is acknowledged for the GC/MS measurements. Douglas Adamson, University of Connecticut, is greatly acknowledged for PEB supply. The financial support of the Ministry of Education through the HRAKLITOS II program, co-financed from the Operational Program and Initial Educational Vocational Training-EPEAEK and the European Social Funds, is greatly appreciated.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Chemical Science Program; KAUST Catalysis Center (KCC)

Full metadata record

DC FieldValue Language
dc.contributor.authorVasilakopoulos, Thodoris C.en
dc.contributor.authorHadjichristidis, Nikolaosen
dc.date.accessioned2015-08-03T10:37:39Zen
dc.date.available2015-08-03T10:37:39Zen
dc.date.issued2012-11-26en
dc.identifier.issn0887624Xen
dc.identifier.doi10.1002/pola.26435en
dc.identifier.urihttp://hdl.handle.net/10754/562422en
dc.description.abstractThe strong influence of (1,3-phenylene)bis(3-methyl-1-phenyl pentylidene)dilithium initiator (DLI) concentration on the modality of polybutadiene (PBd) in the presence of lithium s-butoxide (s-BuOLi) in benzene, at room temperature, has been studied. The quality of DLI has been evaluated by gas chromatography-mass spectrometry (GC-MS) and 1H NMR. Keeping s-BuOLi/C-Li ratio (R) close to unity, at relatively high DLI concentrations (C > 7 × 10-4 M), monomodal high 1,4-PBds with polydispersity index less than 1.07 were obtained, whereas bimodal ones at lower concentrations (C < 6 × 10-4 M). The effect of C-Li concentration on the modality of PBd has been evaluated using size exclusion chromatography on samples taken during and at the end of the polymerization. Viscosity observations have also been used to further support the results. The bimodality of PBd has been attributed to partially terminated difunctional species because of the inevitable presence of protic impurities in the polymerization solution, although high vacuum technique was used, which becomes more significant at low initiator concentrations. Moreover, the strong influence of s-BuOLi on the microstructure of PBd has been demonstrated by 1H NMR. © 2012 Wiley Periodicals, Inc.en
dc.description.sponsorshipThe authors thank J. Roovers for the invaluable suggestions and comments. Stavroula Batistatou, University of Athens, is acknowledged for the GC/MS measurements. Douglas Adamson, University of Connecticut, is greatly acknowledged for PEB supply. The financial support of the Ministry of Education through the HRAKLITOS II program, co-financed from the Operational Program and Initial Educational Vocational Training-EPEAEK and the European Social Funds, is greatly appreciated.en
dc.publisherWiley-Blackwellen
dc.subjectanionic polymerizationen
dc.subjectbimodalityen
dc.subjectdilithium initiator concentrationen
dc.subjectgel permeation chromatography (GPC)en
dc.subjecthigh vacuum techniquesen
dc.subjectlithium s-butoxideen
dc.subjectpolybutadieneen
dc.titleInfluence of (1,3-phenylene)bis(3-methyl-1-phenyl pentylidene)dilithium initiator concentration on the modality of polybutadieneen
dc.typeArticleen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentChemical Science Programen
dc.contributor.departmentPolymer Synthesis Laboratoryen
dc.identifier.journalJournal of Polymer Science Part A: Polymer Chemistryen
dc.contributor.institutionDepartment of Chemistry, University of Athens, Panepistimiopolis, Zografou, 15771 Athens, Greeceen
kaust.authorHadjichristidis, Nikolaosen
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