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Multiblock Thermoplastic Polyurethanes: In Situ Studies of Structural and Morphological Evolution under Strain

The structural evolution of multiblock thermoplastic polyurethane ureas based on two polydiols, poly(1,4-butylene adipate (PBA) and poly-ε-caprolactone (PCL), as soft blocks and two diisocyanites, 2,4-toluylene diisocyanate (TDI) and 1,6-hexamethylene diisocyanate (HMDI), as hard blocks is monitored...

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Autores principales: Anokhin, Denis V., Gorbunova, Marina A., Abukaev, Ainur F., Ivanov, Dimitri A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8199508/
https://www.ncbi.nlm.nih.gov/pubmed/34206146
http://dx.doi.org/10.3390/ma14113009
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author Anokhin, Denis V.
Gorbunova, Marina A.
Abukaev, Ainur F.
Ivanov, Dimitri A.
author_facet Anokhin, Denis V.
Gorbunova, Marina A.
Abukaev, Ainur F.
Ivanov, Dimitri A.
author_sort Anokhin, Denis V.
collection PubMed
description The structural evolution of multiblock thermoplastic polyurethane ureas based on two polydiols, poly(1,4-butylene adipate (PBA) and poly-ε-caprolactone (PCL), as soft blocks and two diisocyanites, 2,4-toluylene diisocyanate (TDI) and 1,6-hexamethylene diisocyanate (HMDI), as hard blocks is monitored during in situ deformation by small- and wide-angle X-ray scattering. It was shown that the urethane environment determines the crystal structure of the soft block. Consequently, two populations of crystalline domains of polydiols are formed. Aromatic TDI forms rigid domains and imposes constrains on the crystallization of bounded polydiol. During stretching, the TDI–polydiol domains reveal limited elastic deformation without reorganization of the crystalline phase. The constrained lamellae of polydiol form an additional physical network that contributes to the elastic modulus and strength of the material. In contrast, polydiols connected to the linear semi-flexible HMDI have a higher crystallization rate and exhibit a more regular lamellar morphology. During deformation, the HMDI-PBA domains show a typical thermoplastic behavior with plastic flow and necking because of the high degree of crystallinity of PBA at room temperature. Materials with HMDI-PCL bonding exhibit elastic deformation due to the low degree of crystallinity of the PCL block in the isotropic state. At higher strain, hardening of the material is observed due to the stress-induced crystallization of PCL.
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spelling pubmed-81995082021-06-14 Multiblock Thermoplastic Polyurethanes: In Situ Studies of Structural and Morphological Evolution under Strain Anokhin, Denis V. Gorbunova, Marina A. Abukaev, Ainur F. Ivanov, Dimitri A. Materials (Basel) Article The structural evolution of multiblock thermoplastic polyurethane ureas based on two polydiols, poly(1,4-butylene adipate (PBA) and poly-ε-caprolactone (PCL), as soft blocks and two diisocyanites, 2,4-toluylene diisocyanate (TDI) and 1,6-hexamethylene diisocyanate (HMDI), as hard blocks is monitored during in situ deformation by small- and wide-angle X-ray scattering. It was shown that the urethane environment determines the crystal structure of the soft block. Consequently, two populations of crystalline domains of polydiols are formed. Aromatic TDI forms rigid domains and imposes constrains on the crystallization of bounded polydiol. During stretching, the TDI–polydiol domains reveal limited elastic deformation without reorganization of the crystalline phase. The constrained lamellae of polydiol form an additional physical network that contributes to the elastic modulus and strength of the material. In contrast, polydiols connected to the linear semi-flexible HMDI have a higher crystallization rate and exhibit a more regular lamellar morphology. During deformation, the HMDI-PBA domains show a typical thermoplastic behavior with plastic flow and necking because of the high degree of crystallinity of PBA at room temperature. Materials with HMDI-PCL bonding exhibit elastic deformation due to the low degree of crystallinity of the PCL block in the isotropic state. At higher strain, hardening of the material is observed due to the stress-induced crystallization of PCL. MDPI 2021-06-01 /pmc/articles/PMC8199508/ /pubmed/34206146 http://dx.doi.org/10.3390/ma14113009 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Anokhin, Denis V.
Gorbunova, Marina A.
Abukaev, Ainur F.
Ivanov, Dimitri A.
Multiblock Thermoplastic Polyurethanes: In Situ Studies of Structural and Morphological Evolution under Strain
title Multiblock Thermoplastic Polyurethanes: In Situ Studies of Structural and Morphological Evolution under Strain
title_full Multiblock Thermoplastic Polyurethanes: In Situ Studies of Structural and Morphological Evolution under Strain
title_fullStr Multiblock Thermoplastic Polyurethanes: In Situ Studies of Structural and Morphological Evolution under Strain
title_full_unstemmed Multiblock Thermoplastic Polyurethanes: In Situ Studies of Structural and Morphological Evolution under Strain
title_short Multiblock Thermoplastic Polyurethanes: In Situ Studies of Structural and Morphological Evolution under Strain
title_sort multiblock thermoplastic polyurethanes: in situ studies of structural and morphological evolution under strain
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8199508/
https://www.ncbi.nlm.nih.gov/pubmed/34206146
http://dx.doi.org/10.3390/ma14113009
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