Layer structure formation of mesogenic liquid crystalline epoxy resin during curing reactions: A reactive coarse-grained molecular dynamics study

Liquid crystalline epoxy resins have been reported to show superior mechanical and thermal properties. This high functionality is attributed to their meso- or macroscopic layered domain structure and their molecular scale ordering; hence, elucidation of the mechanism of layer formation during curing...

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Autores principales: Taisuke SUGII, Hiroshi ITO, Shigenori MATSUMOTO, Shingo TANAKA, Hiroshi MORIYA, Naoki MARUYAMA, Minoru HOSHINO, Naotaka TANAKA, Yoshitaka TAKEZAWA
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Lenguaje:EN
Publicado: The Japan Society of Mechanical Engineers 2021
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Acceso en línea:https://doaj.org/article/8e180d47566142c29310260633d298c7
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spelling oai:doaj.org-article:8e180d47566142c29310260633d298c72021-11-29T06:07:02ZLayer structure formation of mesogenic liquid crystalline epoxy resin during curing reactions: A reactive coarse-grained molecular dynamics study2187-974510.1299/mej.20-00328https://doaj.org/article/8e180d47566142c29310260633d298c72021-04-01T00:00:00Zhttps://www.jstage.jst.go.jp/article/mej/8/3/8_20-00328/_pdf/-char/enhttps://doaj.org/toc/2187-9745Liquid crystalline epoxy resins have been reported to show superior mechanical and thermal properties. This high functionality is attributed to their meso- or macroscopic layered domain structure and their molecular scale ordering; hence, elucidation of the mechanism of layer formation during curing reactions is necessary for material development. In this study, the layer formation process has been investigated by the reactive coarse-grained molecular dynamics method. A mesogenic liquid crystalline epoxy and a typical non-mesogenic epoxy (diglycidyl ether of bisphenol A), mixed with a curing agent 4,4′-DDS (diaminodiphenyl sulfone), were considered. The results clearly showed that the mesogenic epoxy molecules formed a layer structure, whereas the non-mesogenic epoxy molecules remained as the amorphous structure even after the curing reactions. This difference was assumed to be caused by the straight structure of the mesogenic epoxy molecules and the strong attractive interactions between mesogenic parts. The interlayer spacing calculated by the simulation was in close agreement with the X-ray measurement. The details of the curing reaction process, e.g. the conversion and the molecular size in the mesogenic epoxy system, were also investigated. A large layer structure covered the simulation system after the stage in which the first reaction of the amine group was dominant, but the molecules were not large: the molecules were mainly attracted by the non-bond interactions. With the progress of the second reaction of the amine group, by which the tertiary amine was formed from the secondary amine, the molecular size became large and a rigid layer structure was formed over the whole simulation system. These results clearly indicated the role of the curing reactions: the first reaction produced small molecules from monomers and made them align in a layer form, and the second reaction connected them by cross-linking bonds and that produced rigid and large domains.Taisuke SUGIIHiroshi ITOShigenori MATSUMOTOShingo TANAKAHiroshi MORIYANaoki MARUYAMAMinoru HOSHINONaotaka TANAKAYoshitaka TAKEZAWAThe Japan Society of Mechanical Engineersarticlemolecular dynamics simulationcoarse-grained molecular dynamics simulationmesogenic epoxy resincuring reactioncross-linking reactionlayer structureMechanical engineering and machineryTJ1-1570ENMechanical Engineering Journal, Vol 8, Iss 3, Pp 20-00328-20-00328 (2021)
institution DOAJ
collection DOAJ
language EN
topic molecular dynamics simulation
coarse-grained molecular dynamics simulation
mesogenic epoxy resin
curing reaction
cross-linking reaction
layer structure
Mechanical engineering and machinery
TJ1-1570
spellingShingle molecular dynamics simulation
coarse-grained molecular dynamics simulation
mesogenic epoxy resin
curing reaction
cross-linking reaction
layer structure
Mechanical engineering and machinery
TJ1-1570
Taisuke SUGII
Hiroshi ITO
Shigenori MATSUMOTO
Shingo TANAKA
Hiroshi MORIYA
Naoki MARUYAMA
Minoru HOSHINO
Naotaka TANAKA
Yoshitaka TAKEZAWA
Layer structure formation of mesogenic liquid crystalline epoxy resin during curing reactions: A reactive coarse-grained molecular dynamics study
description Liquid crystalline epoxy resins have been reported to show superior mechanical and thermal properties. This high functionality is attributed to their meso- or macroscopic layered domain structure and their molecular scale ordering; hence, elucidation of the mechanism of layer formation during curing reactions is necessary for material development. In this study, the layer formation process has been investigated by the reactive coarse-grained molecular dynamics method. A mesogenic liquid crystalline epoxy and a typical non-mesogenic epoxy (diglycidyl ether of bisphenol A), mixed with a curing agent 4,4′-DDS (diaminodiphenyl sulfone), were considered. The results clearly showed that the mesogenic epoxy molecules formed a layer structure, whereas the non-mesogenic epoxy molecules remained as the amorphous structure even after the curing reactions. This difference was assumed to be caused by the straight structure of the mesogenic epoxy molecules and the strong attractive interactions between mesogenic parts. The interlayer spacing calculated by the simulation was in close agreement with the X-ray measurement. The details of the curing reaction process, e.g. the conversion and the molecular size in the mesogenic epoxy system, were also investigated. A large layer structure covered the simulation system after the stage in which the first reaction of the amine group was dominant, but the molecules were not large: the molecules were mainly attracted by the non-bond interactions. With the progress of the second reaction of the amine group, by which the tertiary amine was formed from the secondary amine, the molecular size became large and a rigid layer structure was formed over the whole simulation system. These results clearly indicated the role of the curing reactions: the first reaction produced small molecules from monomers and made them align in a layer form, and the second reaction connected them by cross-linking bonds and that produced rigid and large domains.
format article
author Taisuke SUGII
Hiroshi ITO
Shigenori MATSUMOTO
Shingo TANAKA
Hiroshi MORIYA
Naoki MARUYAMA
Minoru HOSHINO
Naotaka TANAKA
Yoshitaka TAKEZAWA
author_facet Taisuke SUGII
Hiroshi ITO
Shigenori MATSUMOTO
Shingo TANAKA
Hiroshi MORIYA
Naoki MARUYAMA
Minoru HOSHINO
Naotaka TANAKA
Yoshitaka TAKEZAWA
author_sort Taisuke SUGII
title Layer structure formation of mesogenic liquid crystalline epoxy resin during curing reactions: A reactive coarse-grained molecular dynamics study
title_short Layer structure formation of mesogenic liquid crystalline epoxy resin during curing reactions: A reactive coarse-grained molecular dynamics study
title_full Layer structure formation of mesogenic liquid crystalline epoxy resin during curing reactions: A reactive coarse-grained molecular dynamics study
title_fullStr Layer structure formation of mesogenic liquid crystalline epoxy resin during curing reactions: A reactive coarse-grained molecular dynamics study
title_full_unstemmed Layer structure formation of mesogenic liquid crystalline epoxy resin during curing reactions: A reactive coarse-grained molecular dynamics study
title_sort layer structure formation of mesogenic liquid crystalline epoxy resin during curing reactions: a reactive coarse-grained molecular dynamics study
publisher The Japan Society of Mechanical Engineers
publishDate 2021
url https://doaj.org/article/8e180d47566142c29310260633d298c7
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AT naotakatanaka layerstructureformationofmesogenicliquidcrystallineepoxyresinduringcuringreactionsareactivecoarsegrainedmoleculardynamicsstudy
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