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Klonos PA, Bikiaris ND, Zamboulis A, Valera MÁ, Mangas A, Kyritsis A, Terzopoulou Z. Segmental mobility in sustainable copolymers based on poly(lactic acid) blocks built onto poly(butylene succinate) in situ. SOFT MATTER 2023; 19:7846-7858. [PMID: 37811662 DOI: 10.1039/d3sm00980g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Two series of newly synthesized sustainable block copolymers based on poly(butylene succinate) (PBSu) and polylactide (PLA) were studied. The copolymers were synthesized by a ring-opening polymerization of PLA in the presence of two initial PBSu of low molar mass. We focused on the effects of the PBSu/PLA ratio (1/99 up to 15/85), chain length and initial PBSu length on the final thermal transitions in the copolymers with an emphasis on molecular mobility/dynamics and subsequently on crystallization. Both aspects are considered relevant to the final materials performance, as well as facilitation of polymer renewability. Calorimetry and dielectric spectroscopy were the main investigation tools. In the amorphous state (i.e., in which the direct effects of copolymer structure are assessable), the segmental mobility of neat PLA was significantly faster in the copolymers. Segmental mobility was monitored via the decrease in the calorimetric and dielectric (α relaxation) glass-transition temperatures, Tg and Tg,diel, respectively. The effect was systematic with an increase in the PBSu/PLA ratio, and was rationalized through the plasticizing role of PBSu (low-Tg component) and facilitated also by the simultaneous lowering of the chain length in the copolymers. Dielectric spectroscopy allowed evaluation of the dynamical fragility (cooperativity) of chains, which was strongly suppressed in the copolymers. This finding suggested an increase in free volume or a gradual increase of interchain distances. This phenomenon could favor the natural enzymatic degradation of the systems (compostability), which is limited in neat PLA. We recorded enhancement of nucleation and the crystalline fraction in the copolymers that was likely connected with faster chain diffusion. Further lowering of the Tg with the implementation of crystallization was noted (which seemed a controversial effect) but which indicated crystallization-induced phase separation.
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Affiliation(s)
- Panagiotis A Klonos
- Department of Chemistry, Laboratory of Polymer Chemistry and Technology, Aristotle University of Thessaloniki, GR-541 24, Thessaloniki, Greece.
- Department of Physics, National Technical University of Athens, Zografou Campus, 15780, Athens, Greece
| | - Nikolaos D Bikiaris
- Department of Chemistry, Laboratory of Polymer Chemistry and Technology, Aristotle University of Thessaloniki, GR-541 24, Thessaloniki, Greece.
| | - Alexandra Zamboulis
- Department of Chemistry, Laboratory of Polymer Chemistry and Technology, Aristotle University of Thessaloniki, GR-541 24, Thessaloniki, Greece.
| | - Miguel Ángel Valera
- AIMPLAS, Asociación de Investigación de Materiales Plásticos Y Conexas, Carrer de Gustave Eiffel, 4, 46980 Paterna, Valencia, Spain
| | - Ana Mangas
- AIMPLAS, Asociación de Investigación de Materiales Plásticos Y Conexas, Carrer de Gustave Eiffel, 4, 46980 Paterna, Valencia, Spain
| | - Apostolos Kyritsis
- Department of Physics, National Technical University of Athens, Zografou Campus, 15780, Athens, Greece
| | - Zoi Terzopoulou
- Department of Chemistry, Laboratory of Polymer Chemistry and Technology, Aristotle University of Thessaloniki, GR-541 24, Thessaloniki, Greece.
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Klonos PA, Terzopoulou Z, Zamboulis A, Valera MÁ, Mangas A, Kyritsis A, Pissis P, Bikiaris DN. Direct and indirect effects on molecular mobility in renewable polylactide-poly(propylene adipate) block copolymers as studied via dielectric spectroscopy and calorimetry. SOFT MATTER 2022; 18:3725-3737. [PMID: 35503564 DOI: 10.1039/d2sm00261b] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In this work, we study a series of sustainable block copolymers based on polylactide, PLA, and poly(propylene adipate), PPAd, both polymers being prepared from renewable resources. Envisaging a wide range of future applications in the frame of a green and circular economy, e.g., packaging materials replacing conventional petrochemicals, the employment of PPAd aims at lowering the glass transition and melting temperatures of PLA and, finally, facilitation of the enzymatic degradation and compostability. The copolymers have been synthesized via ring opening polymerization of lactides in the presence of propylene adipate oligomers (5, 15 and 25%). The direct effects on the molecular mobility by the structure/composition are assessed in the amorphous state employing broadband dielectric spectroscopy (BDS) and calorimetry. BDS allowed the recording of local PLA and PPAd dynamics in all cases. The effects on local relaxations suggest favoring of interchain interactions, both PLA-PPAd and PPAd-PPAd. Regarding the more important segmental dynamics, the presence of PPAd leads to faster polymer chain diffusion, as monitored by the significant lowering of the dielectric and calorimetric glass transition temperature, Tg. This suggests the plasticizing role of PPAd on PLA (majority) in combination with the lowering of the average molar mass, Mn, in the copolymers from ∼75 to ∼30 kg mol-1, which is the actual scope for the synthesis of these materials. Interestingly, a strong suppression in fragility (chain cooperativity) is additionally recorded. In contrast to calorimetry and due to the high resolving power of BDS, for the higher PPAd fraction, the weak segmental relaxation of PPAd was additionally recorded. Overall, the recordings suggest a strong increase in free volume and two individual dynamic states, one for 0 and 5% PPAd and another for 15 and 25% PPAd. Within the latter, we gained indications for partial phase nano-separation of PPAd. Regarding indirect effects, these were followed via crystallization. Independent of the method of crystallization, namely, melt or cold, the presence of PPAd led to the systematic lowering of crystallization and melting temperatures and enthalpies. The effects reflect the decrease of crystalline nuclei, which is confirmed by optical microscopy as in the copolymers fewer although larger crystals are formed.
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Affiliation(s)
- Panagiotis A Klonos
- Department of Chemistry, Laboratory of Polymer Chemistry and Technology, Aristotle University of Thessaloniki, GR-541 24, Thessaloniki, Greece.
- Department of Physics, National Technical University of Athens (NTUA), Zografou Campus, 15780, Athens, Greece
| | - Zoi Terzopoulou
- Department of Chemistry, Laboratory of Polymer Chemistry and Technology, Aristotle University of Thessaloniki, GR-541 24, Thessaloniki, Greece.
| | - Alexandra Zamboulis
- Department of Chemistry, Laboratory of Polymer Chemistry and Technology, Aristotle University of Thessaloniki, GR-541 24, Thessaloniki, Greece.
| | - Miguel Ángel Valera
- AIMPLAS, Asociación de Investigación de Materiales Plásticos Y Conexas, Carrer de Gustave Eiffel, 4, 46980 Valencia, Spain
| | - Ana Mangas
- AIMPLAS, Asociación de Investigación de Materiales Plásticos Y Conexas, Carrer de Gustave Eiffel, 4, 46980 Valencia, Spain
| | - Apostolos Kyritsis
- Department of Physics, National Technical University of Athens (NTUA), Zografou Campus, 15780, Athens, Greece
| | - Polycarpos Pissis
- Department of Physics, National Technical University of Athens (NTUA), Zografou Campus, 15780, Athens, Greece
| | - Dimitrios N Bikiaris
- Department of Chemistry, Laboratory of Polymer Chemistry and Technology, Aristotle University of Thessaloniki, GR-541 24, Thessaloniki, Greece.
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Pascual-Jose B, Badia J, Múgica A, Addiego F, Müller AJ, Ribes-Greus A. Analysis of plasticization and reprocessing effects on the segmental cooperativity of polylactide by dielectric thermal spectroscopy. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.123701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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4
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Kolek Ł, Jasiurkowska-Delaporte M, Juszyńska-Gałązka E. Kinetics of non-isothermal cold crystallization in the antiferroelectric smectic phase of 3F5BFBiHex as seen by differential scanning calorimetry and broadband dielectric spectroscopy. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.115040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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5
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Klonos P, Pissis P. Effects of interfacial interactions and of crystallization on rigid amorphous fraction and molecular dynamics in polylactide/silica nanocomposites: A methodological approach. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.02.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Klonos P, Kulyk K, Borysenko MV, Gun’ko VM, Kyritsis A, Pissis P. Effects of Molecular Weight below the Entanglement Threshold on Interfacial Nanoparticles/Polymer Dynamics. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01931] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Panagiotis Klonos
- Department of Physics, National Technical University of Athens, Zografou Campus, 15780 Athens, Greece
| | - Kostiantyn Kulyk
- Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Mykola V. Borysenko
- Chuiko Institute of Surface Chemistry, National Academy of Sciences of Ukraine, 17 General Naumov Street, Kiev 03164, Ukraine
| | - Vladimir M. Gun’ko
- Chuiko Institute of Surface Chemistry, National Academy of Sciences of Ukraine, 17 General Naumov Street, Kiev 03164, Ukraine
| | - Apostolos Kyritsis
- Department of Physics, National Technical University of Athens, Zografou Campus, 15780 Athens, Greece
| | - Polycarpos Pissis
- Department of Physics, National Technical University of Athens, Zografou Campus, 15780 Athens, Greece
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8
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Merino EG, Danéde F, Derrollez P, Dias CJ, Viciosa MT, Correia NT, Dionísio M. Investigating the Influence of Morphology in the Dynamical Behavior of Semicrystalline Triton X-100: Insights in the Detection/Nondetection of the α′-Process. J Phys Chem B 2013; 117:9793-805. [DOI: 10.1021/jp4042414] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Esther G. Merino
- REQUIMTE/CQFB, Departamento
de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Florence Danéde
- Unité Matériaux
Et Transformations (UMET), UMR CNRS 8207, UFR de Physique, BAT P5, Université Lille Nord de France, F-59655 Villeneuve
d’Ascq Cedex, France
| | - Patrick Derrollez
- Unité Matériaux
Et Transformations (UMET), UMR CNRS 8207, UFR de Physique, BAT P5, Université Lille Nord de France, F-59655 Villeneuve
d’Ascq Cedex, France
| | - Carlos J. Dias
- CENIMAT/I3N, Departamento de Ciência
dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - M. Teresa Viciosa
- CQFM—Centro de Química-Física
Molecular and IN—Institute of Nanoscience and Nanotechnology,
Instituto Superior Técnico, Universidade Técnica de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Natália T. Correia
- REQUIMTE/CQFB, Departamento
de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
- Unité Matériaux
Et Transformations (UMET), UMR CNRS 8207, UFR de Physique, BAT P5, Université Lille Nord de France, F-59655 Villeneuve
d’Ascq Cedex, France
| | - Madalena Dionísio
- REQUIMTE/CQFB, Departamento
de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
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9
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Merino EG, Rodrigues C, Viciosa MT, Melo C, Sotomayor J, Dionísio M, Correia NT. Phase Transformations Undergone by Triton X-100 Probed by Differential Scanning Calorimetry and Dielectric Relaxation Spectroscopy. J Phys Chem B 2011; 115:12336-47. [DOI: 10.1021/jp2028033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Esther G. Merino
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Carla Rodrigues
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - M. Teresa Viciosa
- CQFM − Centro de Química-Física Molecular and IN − Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade Técnica de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Carlos Melo
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - João Sotomayor
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Madalena Dionísio
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Natália T. Correia
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
- Unité Matériaux et Transformation (UMET), UMR CNRS 8207, UFR de Physique, BAT P5, Université Lille 1, 59655 Villeneuve d’Ascq, France
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10
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Physical and chemical modifications of thiol-ene networks to control activation energy of enthalpy relaxation. POLYMER 2009. [DOI: 10.1016/j.polymer.2009.10.053] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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11
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Wurm A, Minakov AA, Schick C. Combining X-ray scattering with dielectric and calorimetric experiments for monitoring polymer crystallization. Eur Polym J 2009. [DOI: 10.1016/j.eurpolymj.2009.07.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Viciosa MT, Correia NT, Sánchez MS, Gómez Ribelles JL, Dionísio M. Molecular Dynamics of Ethylene Glycol Dimethacrylate Glass Former: Influence of Different Crystallization Pathways. J Phys Chem B 2009; 113:14196-208. [DOI: 10.1021/jp903208k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- María T. Viciosa
- REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal., Centro de Biomateriales e Ingeniería Tisular, Universidad Politécnica de Valencia, Camino de Vera s/n, E-46022 Valencia, Spain, Centro de Investigación Príncipe Felipe, Avda. Autopista del Saler 16, 46013 Valencia, Spain, and CIBER en Bioingeniería, Biomateriales y Nanomedicina, Valencia, Spain
| | - Natália T. Correia
- REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal., Centro de Biomateriales e Ingeniería Tisular, Universidad Politécnica de Valencia, Camino de Vera s/n, E-46022 Valencia, Spain, Centro de Investigación Príncipe Felipe, Avda. Autopista del Saler 16, 46013 Valencia, Spain, and CIBER en Bioingeniería, Biomateriales y Nanomedicina, Valencia, Spain
| | - Manuel Salmerón Sánchez
- REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal., Centro de Biomateriales e Ingeniería Tisular, Universidad Politécnica de Valencia, Camino de Vera s/n, E-46022 Valencia, Spain, Centro de Investigación Príncipe Felipe, Avda. Autopista del Saler 16, 46013 Valencia, Spain, and CIBER en Bioingeniería, Biomateriales y Nanomedicina, Valencia, Spain
| | - José L. Gómez Ribelles
- REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal., Centro de Biomateriales e Ingeniería Tisular, Universidad Politécnica de Valencia, Camino de Vera s/n, E-46022 Valencia, Spain, Centro de Investigación Príncipe Felipe, Avda. Autopista del Saler 16, 46013 Valencia, Spain, and CIBER en Bioingeniería, Biomateriales y Nanomedicina, Valencia, Spain
| | - Madalena Dionísio
- REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal., Centro de Biomateriales e Ingeniería Tisular, Universidad Politécnica de Valencia, Camino de Vera s/n, E-46022 Valencia, Spain, Centro de Investigación Príncipe Felipe, Avda. Autopista del Saler 16, 46013 Valencia, Spain, and CIBER en Bioingeniería, Biomateriales y Nanomedicina, Valencia, Spain
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13
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Viciosa MT, Correia NT, Sanchez MS, Carvalho AL, Romão MJ, Gómez Ribelles JL, Dionísio M. Real-Time Monitoring of Molecular Dynamics of Ethylene Glycol Dimethacrylate Glass Former. J Phys Chem B 2009; 113:14209-17. [DOI: 10.1021/jp903212g] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. T. Viciosa
- REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, CQFM - Centro de Química-Física Molecular and IN - Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade Técnica de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal, Centro de Biomateriales e Ingeniería Tisular, Universidad Politécnica de Valencia, Camino de Vera s/n, E-46022 Valencia, Spain, Centro de Investigación Príncipe Felipe, Avda
| | - N. T. Correia
- REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, CQFM - Centro de Química-Física Molecular and IN - Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade Técnica de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal, Centro de Biomateriales e Ingeniería Tisular, Universidad Politécnica de Valencia, Camino de Vera s/n, E-46022 Valencia, Spain, Centro de Investigación Príncipe Felipe, Avda
| | - M. Salmerón Sanchez
- REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, CQFM - Centro de Química-Física Molecular and IN - Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade Técnica de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal, Centro de Biomateriales e Ingeniería Tisular, Universidad Politécnica de Valencia, Camino de Vera s/n, E-46022 Valencia, Spain, Centro de Investigación Príncipe Felipe, Avda
| | - A. L. Carvalho
- REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, CQFM - Centro de Química-Física Molecular and IN - Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade Técnica de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal, Centro de Biomateriales e Ingeniería Tisular, Universidad Politécnica de Valencia, Camino de Vera s/n, E-46022 Valencia, Spain, Centro de Investigación Príncipe Felipe, Avda
| | - M. J. Romão
- REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, CQFM - Centro de Química-Física Molecular and IN - Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade Técnica de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal, Centro de Biomateriales e Ingeniería Tisular, Universidad Politécnica de Valencia, Camino de Vera s/n, E-46022 Valencia, Spain, Centro de Investigación Príncipe Felipe, Avda
| | - J. L. Gómez Ribelles
- REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, CQFM - Centro de Química-Física Molecular and IN - Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade Técnica de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal, Centro de Biomateriales e Ingeniería Tisular, Universidad Politécnica de Valencia, Camino de Vera s/n, E-46022 Valencia, Spain, Centro de Investigación Príncipe Felipe, Avda
| | - M. Dionísio
- REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, CQFM - Centro de Química-Física Molecular and IN - Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade Técnica de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal, Centro de Biomateriales e Ingeniería Tisular, Universidad Politécnica de Valencia, Camino de Vera s/n, E-46022 Valencia, Spain, Centro de Investigación Príncipe Felipe, Avda
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Pieruccini M, Ezquerra TA. Segmental relaxation in semicrystalline polymers: a mean-field model for the distribution of relaxation times in confined regimes. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2009; 29:163-171. [PMID: 19517149 DOI: 10.1140/epje/i2009-10464-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 03/26/2009] [Accepted: 04/23/2009] [Indexed: 05/27/2023]
Abstract
The effect of confinement in the segmental relaxation of polymers is considered. On the basis of a thermodynamic model we discuss the emerging relevance of the fast degrees of freedom in stimulating the much slower segmental relaxation, as an effect of the constraints at the walls of the amorphous regions. In the case that confinement is due to the presence of crystalline domains, a quasi-Poissonian distribution of local constraining conditions is derived as a result of thermodynamic equilibrium. This implies that the average free-energy barrier DeltaF for conformational rearrangement is of the same order of the dispersion of the barrier heights, delta(DeltaF) , around DeltaF. As an example, we apply the results to the analysis of the alpha-relaxation as observed by dielectric broad-band spectroscopy in semicrystalline poly(ethylene terephthalate) cold-crystallized from either an isotropic or an oriented glass. It is found that in the latter case the regions of cooperative rearrangement are significantly larger than in the former.
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Affiliation(s)
- M Pieruccini
- Messina, Salita Sperone Contrada Papardo, CNR, Istituto per i Processi Chimico-Fisici, sn 98158 Faro Superiore, Messina, Italy.
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15
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Li ZH, Wong MS, Tao Y, Fukutani H. Ambipolar Diphenylamino End-Capped Oligofluorenylthiophenes as Excellent Electron-Transporting Emitters. Org Lett 2007; 9:3659-62. [PMID: 17665926 DOI: 10.1021/ol701561s] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In addition to hole transport, diphenylamino-end-capped oligofluorenylthiophenes can exhibit efficient electron transport, in which the oligothiophene central core acts as an excellent electron-transporting moiety. The highly efficient undoped multilayer OLEDs using OF(2)TTP-NPh and OF(2)QTP-NPh as an electron-transporting emitter exhibited a maximum luminance of 19,800 and 11,800 cd m(-2) with a luminance efficiency up to 5.3 and 1.0 cd A(-1), respectively.
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Affiliation(s)
- Zhong Hui Li
- Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Hong Kong SAR, China
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Alie J, Menegotto J, Cardon P, Duplaa H, Caron A, Lacabanne C, Bauer M. Dielectric study of the molecular mobility and the isothermal crystallization kinetics of an amorphous pharmaceutical drug substance. J Pharm Sci 2004; 93:218-33. [PMID: 14648651 DOI: 10.1002/jps.10520] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
During the development of new pharmaceutical products based on drug substances in their amorphous form, the molecular mobility of an amorphous active ingredient was characterized in detail within a very broad time-temperature range. The relation between the isothermal crystallization kinetics and the dynamics of this amorphous substance was investigated. First, dynamic dielectric spectroscopy (DDS) and the thermostimulated current (TSC) techniques were used to analyze the molecular mobility of the amorphous drug substance over a wide frequency and temperature range (the drug substance is referred to as SSR in this text and was chosen as a model glass-forming system). Two relaxation processes, corresponding to different molecular motions, were identified. The beta(a)-relaxation process, associated with intramolecular oscillation of small dipolar groups, followed Arrhenius temperature behavior over the entire time-temperature domain that was studied. However, the main alpha(a)-relaxation process, assigned to the dielectric manifestation of the dynamic glass transition of the amorphous phase, was described by Vogel-Fulcher-Tammann (VFT) and Arrhenius behavior above and below the glass transition temperature (T(g)) respectively. The physical meaning of these complex dynamics is explained in the context of the Adam and Gibbs (AG) model, by the temperature dependence of the size of cooperatively rearranging regions (CRR) that govern the time scale of delocalized molecular motions. The distinction between the molecular mobility and the structural relaxation of amorphous systems below T(g) is discussed. This work shows that the complementary nature of both DDS and TSC techniques is essential to directly analyze the intramolecular and molecular motions of disordered phases over a wide time-temperature range above and below the T(g). Second, real-time dielectric measurements were carried out to determine the isothermal crystallization kinetics of the SSR amorphous drug. Whatever the crystalline form obtained over time in the crystallization process, the decrease of the dielectric response of amorphous phase, which is characteristic of the isothermal crystallization, was studied to monitor the time dependence of the degree of crystallinity. The characteristic crystallization time, derived from Kohlrausch-Williams-Watt (KWW)-Avrami analyses performed at different temperatures, followed an Arrhenius temperature dependence. Behaviors specific to the molecular mobility of the amorphous drug substance were compared with the characteristic crystallization time. It was concluded that the crystal growth process of the SSR drug seems to be controlled by the intramolecular motions involving the beta(a)-relaxation mode and not by the molecular motions responsible for the alpha(a)-relaxation mode in the range of temperatures >T(g). Subsequent studies will focus on the crystallization process of the SSR drug in the glassy state (T < T(g)).
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Affiliation(s)
- J Alie
- Polymer Physics Laboratory, CIRIMAT UMR 5085, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex, France
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Lu H, Nutt S. Restricted Relaxation in Polymer Nanocomposites near the Glass Transition. Macromolecules 2003. [DOI: 10.1021/ma034049b] [Citation(s) in RCA: 202] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hongbin Lu
- MCGF Composites Center, Department of Materials Science, University of Southern California, Los Angeles, California 90089
| | - Steven Nutt
- MCGF Composites Center, Department of Materials Science, University of Southern California, Los Angeles, California 90089
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Ezquerra TA, Nogales A. Probing Crystallization Studying Amorphous Phase Evolution. POLYMER CRYSTALLIZATION 2003. [DOI: 10.1007/3-540-45851-4_15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Moreno S, Rubio RG. Dielectric Study of the Dynamics of Poly(oxyethylene) Chains in Triblock Copolymers: Poly(oxyethylene)-b-polystyrene-b-poly(oxyethylene). Macromolecules 2002. [DOI: 10.1021/ma011732u] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Susana Moreno
- Department Química Física I, Facultad de Química, Universidad Complutense, 28040-Madrid, Spain
| | - Ramón G. Rubio
- Department Química Física I, Facultad de Química, Universidad Complutense, 28040-Madrid, Spain
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Vatalis AS, Kanapitsas A, Delides CG, Viras K, Pissis P. Phase behavior and molecular mobility in polyurethane/styrene-acrylonitrile blends. J Appl Polym Sci 2001. [DOI: 10.1002/app.1192] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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