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dc.contributor.authorZaldua Carazo, Nerea
dc.contributor.authorLiénard, Romain
dc.contributor.authorJosse, Thomas
dc.contributor.authorZubitur Soroa, María Manuela
dc.contributor.authorMúgica Iztueta, Agurtzane
dc.contributor.authorIturrospe Ibarra, Amaia
dc.contributor.authorArbe Méndez, María Aranzazu
dc.contributor.authorDe Winter, Julien
dc.contributor.authorCoulembier, Olivier
dc.contributor.authorMüller Sánchez, Alejandro Jesús
dc.date.accessioned2019-06-03T14:06:17Z
dc.date.available2019-06-03T14:06:17Z
dc.date.issued2018-02-20
dc.identifier.citationMacromolecules 51(5) : 1718−1732 (2018)es_ES
dc.identifier.issn0024-9297
dc.identifier.urihttp://hdl.handle.net/10810/33072
dc.description.abstractIn this paper, ring closure click chemistry methods have been used to produce cyclic c-PLLA and c-PDLA of a number average molecular weight close to 10 kg/mol. The effects of stereochemistry of the polymer chains and their topology on their structure, nucleation and crystallization were studied in detail employing Wide Angle X-ray Scattering (WAXS), Small Angle X-ray Scattering (SAXS), Polarized Light Optical Microscopy (PLOM) and standard and advanced Differential Scanning Calorimetry (DSC). The crystal structures of linear and cyclic PLAs are identical to each other and no differences in superstructural morphology could be detected. Cyclic PLA chains are able to nucleate much faster and to produce a higher number of nuclei in comparison to linear analogues, either upon cooling from the melt or upon heating from the glassy state. In the samples prepared in this work, a small fraction of linear or higher molecular weight cycles was detected (according to SEC analyses). The presence of such “impurities” retards spherulitic growth rates of c-PLAs making them nearly the same as those of l-PLAs. On the other hand, the overall crystallization rate determined by DSC was much larger for c-PLAs, as a consequence of the enhanced nucleation that occurs in cyclic chains. The equilibrium melting temperatures of cyclic chains were determined and found to be 5 ºC higher in comparison with values for l-PLAs. This result is a consequence of the lower entropy of cyclic chains in the melt. Self-nucleation studies demonstrated that c-PLAs have a shorter crystalline memory than linear analogues, as a result of their lower entanglement density. Successive self-nucleation and annealing (SSA) experiments reveal the remarkable ability of cyclic molecules to thicken, even to the point of crystallization with extended collapsed ring conformations. In general terms, stereochemistry had less influence on the results obtained in comparison with the dominating effect of chain topology.es_ES
dc.description.sponsorship“UPV/EHU Infrastructure: INF 14/38”; “Mineco/FEDER: SINF 130I001726XV1/Ref: UNPV13–4E–1726” and “Mineco MAT2014-53437-C2-P”, 'Ministerio de Economia y Competitividad (MINECO), code: MAT2015-63704-P (MINECO/FEDER, UE) and by the Eusko Jaurlaritza (Basque Government), code: IT-654-13. O.C acknowledges financial support from the European Commission and Région Wallonne FEDER program (Materia Nova) and OPTI²MAT program of excellence, by the Interuniversity Attraction Pole Program (P7/05) initiated by the Belgian Science Policy office and by the FNRS-FRFC. OC is Research Associate of the F.R.S.-FNRS. Organic Synthesis and Mass Spectrometry Laboratory thanks F.R.S.-FNRS for the financial support for the acquisition of the Waters QToF Premier and Synapt-G2Si mass spectrometers and for continuing support. Finally, all authors would like to acknowledge Research and Innovation Staff Exchange (RISE) H2020-MSCA-RISE-2017-778092, project BIODEST for promoting cooperation between the Mons team and the UPV/EHU team.es_ES
dc.language.isoenges_ES
dc.publisherAmerican Chemical Societyes_ES
dc.relationinfo:eu-repo/grantAgreement/EC/H2020/778092es_ES
dc.relationinfo:eu-repo/grantAgreement/MINECO/MAT2014-53437-C2-Pes_ES
dc.relationinfo:eu-repo/grantAgreement/MINECO/MAT2015-63704-Pes_ES
dc.rightsinfo:eu-repo/semantics/openAccesses_ES
dc.subjectcyclic polymerses_ES
dc.subjectnucleation kineticses_ES
dc.subjectcrystallization kineticses_ES
dc.subjectequilibrium melting pointes_ES
dc.titleInfluence of chain topology (cyclic versus linear) on the nucleation and isothermal crystallization of poly(L-lactide) and poly(D-lactide)es_ES
dc.typeinfo:eu-repo/semantics/articlees_ES
dc.rights.holderCopyright © 2018 American Chemical Societyes_ES
dc.relation.publisherversionhttps://pubs.acs.org/doi/abs/10.1021/acs.macromol.7b02638es_ES
dc.identifier.doi10.1021/acs.macromol.7b02638
dc.contributor.funderEuropean Comission
dc.departamentoesCiencia y tecnología de polímeroses_ES
dc.departamentoeuPolimeroen zientzia eta teknologiaes_ES


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