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Sequential Crystallization and Multicrystalline Morphology in PE-b-PEO-b-PCL-b-PLLA Tetrablock Quarterpolymers
[Image: see text] We investigate for the first time the morphology and crystallization of two novel tetrablock quarterpolymers of polyethylene (PE), poly(ethylene oxide) (PEO), poly(ε-caprolactone) (PCL), and poly(l-lactide) (PLLA) with four potentially crystallizable blocks: PE(18)(7.1)-b-PEO(37)(1...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American
Chemical Society
2021
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9159653/ https://www.ncbi.nlm.nih.gov/pubmed/35663800 http://dx.doi.org/10.1021/acs.macromol.1c01186 |
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author | Matxinandiarena, Eider Múgica, Agurtzane Tercjak, Agnieszka Ladelta, Viko Zapsas, George Hadjichristidis, Nikos Cavallo, Dario Flores, Araceli Müller, Alejandro J. |
author_facet | Matxinandiarena, Eider Múgica, Agurtzane Tercjak, Agnieszka Ladelta, Viko Zapsas, George Hadjichristidis, Nikos Cavallo, Dario Flores, Araceli Müller, Alejandro J. |
author_sort | Matxinandiarena, Eider |
collection | PubMed |
description | [Image: see text] We investigate for the first time the morphology and crystallization of two novel tetrablock quarterpolymers of polyethylene (PE), poly(ethylene oxide) (PEO), poly(ε-caprolactone) (PCL), and poly(l-lactide) (PLLA) with four potentially crystallizable blocks: PE(18)(7.1)-b-PEO(37)(15.1)-b-PCL(26)(10.4)-b-PLLA(19)(7.6) (Q1) and PE(29)(9.5)-b-PEO(26)(8.8)-b-PCL(23)(7.6)-b-PLLA(22)(7.3) (Q2) (superscripts give number average molecular weights in kg/mol, and subscripts give the composition in wt %). Their synthesis was performed by a combination of polyhomologation (C1 polymerization) and ring-opening polymerization techniques using a ″catalyst-switch″ strategy, either ″organocatalyst/metal catalyst switch″ (Q1 sample, 96% isotactic tetrads) or ″organocatalyst/organocatalyst switch″ (Q2 sample, 84% isotactic tetrads). Their corresponding precursors—triblock terpolymers PE-b-PEO-b-PCL, diblock copolymers PE-b-PEO, and PE homopolymers—were also studied. Cooling and heating rates from the melt at 20 °C/min were employed for most experiments: differential scanning calorimetry (DSC), polarized light optical microscopy (PLOM), in situ small-angle X-ray scattering/wide-angle X-ray scattering (SAXS/WAXS), and atomic force microscopy (AFM). The direct comparison of the results obtained with these different techniques allows the precise identification of the crystallization sequence of the blocks upon cooling from the melt. SAXS indicated that Q1 is melt miscible, while Q2 is weakly segregated in the melt but breaks out during crystallization. According to WAXS and DSC results, the blocks follow a sequence as they crystallize: PLLA first, then PE, then PCL, and finally PEO in the case of the Q1 quarterpolymer; in Q2, the PLLA block is not able to crystallize due to its low isotacticity. Although the temperatures at which the PEO and PCL blocks and the PE and PLLA blocks crystallize overlap, the analysis of the intensity changes measured by WAXS and PLOM experiments allows identifying each of the crystallization processes. The quarterpolymer Q1 remarkably self-assembles during crystallization into tetracrystalline banded spherulites, where four types of different lamellae coexist. Nanostructural features arising upon sequential crystallization are found to have a relevant impact on the mechanical properties. Nanoindentation measurements show that storage modulus and hardness of the Q1 quarterpolymer significantly deviate from those of the stiff PE and PLLA blocks, approaching typical values of compliant PEO and PCL. Results are mainly attributed to the low crystallinity of the PE and PLLA blocks. Moreover, the Q2 copolymer exhibits inferior mechanical properties than Q1, and this can be related to the PE block within Q1 that has thinner crystal lamellae according to its much lower melting point. |
format | Online Article Text |
id | pubmed-9159653 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | American
Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-91596532022-06-02 Sequential Crystallization and Multicrystalline Morphology in PE-b-PEO-b-PCL-b-PLLA Tetrablock Quarterpolymers Matxinandiarena, Eider Múgica, Agurtzane Tercjak, Agnieszka Ladelta, Viko Zapsas, George Hadjichristidis, Nikos Cavallo, Dario Flores, Araceli Müller, Alejandro J. Macromolecules [Image: see text] We investigate for the first time the morphology and crystallization of two novel tetrablock quarterpolymers of polyethylene (PE), poly(ethylene oxide) (PEO), poly(ε-caprolactone) (PCL), and poly(l-lactide) (PLLA) with four potentially crystallizable blocks: PE(18)(7.1)-b-PEO(37)(15.1)-b-PCL(26)(10.4)-b-PLLA(19)(7.6) (Q1) and PE(29)(9.5)-b-PEO(26)(8.8)-b-PCL(23)(7.6)-b-PLLA(22)(7.3) (Q2) (superscripts give number average molecular weights in kg/mol, and subscripts give the composition in wt %). Their synthesis was performed by a combination of polyhomologation (C1 polymerization) and ring-opening polymerization techniques using a ″catalyst-switch″ strategy, either ″organocatalyst/metal catalyst switch″ (Q1 sample, 96% isotactic tetrads) or ″organocatalyst/organocatalyst switch″ (Q2 sample, 84% isotactic tetrads). Their corresponding precursors—triblock terpolymers PE-b-PEO-b-PCL, diblock copolymers PE-b-PEO, and PE homopolymers—were also studied. Cooling and heating rates from the melt at 20 °C/min were employed for most experiments: differential scanning calorimetry (DSC), polarized light optical microscopy (PLOM), in situ small-angle X-ray scattering/wide-angle X-ray scattering (SAXS/WAXS), and atomic force microscopy (AFM). The direct comparison of the results obtained with these different techniques allows the precise identification of the crystallization sequence of the blocks upon cooling from the melt. SAXS indicated that Q1 is melt miscible, while Q2 is weakly segregated in the melt but breaks out during crystallization. According to WAXS and DSC results, the blocks follow a sequence as they crystallize: PLLA first, then PE, then PCL, and finally PEO in the case of the Q1 quarterpolymer; in Q2, the PLLA block is not able to crystallize due to its low isotacticity. Although the temperatures at which the PEO and PCL blocks and the PE and PLLA blocks crystallize overlap, the analysis of the intensity changes measured by WAXS and PLOM experiments allows identifying each of the crystallization processes. The quarterpolymer Q1 remarkably self-assembles during crystallization into tetracrystalline banded spherulites, where four types of different lamellae coexist. Nanostructural features arising upon sequential crystallization are found to have a relevant impact on the mechanical properties. Nanoindentation measurements show that storage modulus and hardness of the Q1 quarterpolymer significantly deviate from those of the stiff PE and PLLA blocks, approaching typical values of compliant PEO and PCL. Results are mainly attributed to the low crystallinity of the PE and PLLA blocks. Moreover, the Q2 copolymer exhibits inferior mechanical properties than Q1, and this can be related to the PE block within Q1 that has thinner crystal lamellae according to its much lower melting point. American Chemical Society 2021-07-23 2021-08-10 /pmc/articles/PMC9159653/ /pubmed/35663800 http://dx.doi.org/10.1021/acs.macromol.1c01186 Text en © 2021 American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Matxinandiarena, Eider Múgica, Agurtzane Tercjak, Agnieszka Ladelta, Viko Zapsas, George Hadjichristidis, Nikos Cavallo, Dario Flores, Araceli Müller, Alejandro J. Sequential Crystallization and Multicrystalline Morphology in PE-b-PEO-b-PCL-b-PLLA Tetrablock Quarterpolymers |
title | Sequential Crystallization and Multicrystalline Morphology
in PE-b-PEO-b-PCL-b-PLLA Tetrablock Quarterpolymers |
title_full | Sequential Crystallization and Multicrystalline Morphology
in PE-b-PEO-b-PCL-b-PLLA Tetrablock Quarterpolymers |
title_fullStr | Sequential Crystallization and Multicrystalline Morphology
in PE-b-PEO-b-PCL-b-PLLA Tetrablock Quarterpolymers |
title_full_unstemmed | Sequential Crystallization and Multicrystalline Morphology
in PE-b-PEO-b-PCL-b-PLLA Tetrablock Quarterpolymers |
title_short | Sequential Crystallization and Multicrystalline Morphology
in PE-b-PEO-b-PCL-b-PLLA Tetrablock Quarterpolymers |
title_sort | sequential crystallization and multicrystalline morphology
in pe-b-peo-b-pcl-b-plla tetrablock quarterpolymers |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9159653/ https://www.ncbi.nlm.nih.gov/pubmed/35663800 http://dx.doi.org/10.1021/acs.macromol.1c01186 |
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