Effects of Hydration on the Mechanical Properties of Salt-Doped Poly(methyl methacrylate)

The mechanical performance of poly(methyl methacrylate) (PMMA) is highly sensitive to moisture absorption, which induces plasticization and softening. In this study, we investigated the ductilization mechanism of PMMA by incorporating various metal salts with different cations (Li<sup>+</su...

Full description

Saved in:
Bibliographic Details
Main Authors: Asae Ito, Naoki Uchida, Yusuke Hiejima, Koh-hei Nitta
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Molecules
Subjects:
Online Access:https://www.mdpi.com/1420-3049/30/12/2568
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1849431313702977536
author Asae Ito
Naoki Uchida
Yusuke Hiejima
Koh-hei Nitta
author_facet Asae Ito
Naoki Uchida
Yusuke Hiejima
Koh-hei Nitta
author_sort Asae Ito
collection DOAJ
description The mechanical performance of poly(methyl methacrylate) (PMMA) is highly sensitive to moisture absorption, which induces plasticization and softening. In this study, we investigated the ductilization mechanism of PMMA by incorporating various metal salts with different cations (Li<sup>+</sup> and Mg<sup>2+</sup>) and controlling water absorption through hygroscopic interactions. A nonequilibrium constitutive model is introduced, in which localized water domains around salt-rich regions gradually diffuse into the PMMA matrix during tensile deformation. The stress–strain behavior is described by combining rigid (dry) and soft (hydrated) matrix components, connected through an internal kinetic variable governed by the strain-dependent diffusion rate. The model successfully reproduces experimental tensile data and captures the transition from brittle to ductile behavior as a function of the moisture content. Notably, Mg salts exhibit stronger water binding and slower moisture redistribution than Li salts, resulting in distinct mechanical responses. These findings provide a mechanistic framework for tailoring the ductility of hygroscopic polymer systems via ion–water–polymer interactions.
format Article
id doaj-art-d649e78a50834d1f97d34f35edaa1a33
institution Kabale University
issn 1420-3049
language English
publishDate 2025-06-01
publisher MDPI AG
record_format Article
series Molecules
spelling doaj-art-d649e78a50834d1f97d34f35edaa1a332025-08-20T03:27:40ZengMDPI AGMolecules1420-30492025-06-013012256810.3390/molecules30122568Effects of Hydration on the Mechanical Properties of Salt-Doped Poly(methyl methacrylate)Asae Ito0Naoki Uchida1Yusuke Hiejima2Koh-hei Nitta3Institute of Science and Engineering, Kanazawa University, Kakuma Campus, Kanazawa 920-1192, JapanInstitute of Science and Engineering, Kanazawa University, Kakuma Campus, Kanazawa 920-1192, JapanInstitute of Science and Engineering, Kanazawa University, Kakuma Campus, Kanazawa 920-1192, JapanInstitute of Science and Engineering, Kanazawa University, Kakuma Campus, Kanazawa 920-1192, JapanThe mechanical performance of poly(methyl methacrylate) (PMMA) is highly sensitive to moisture absorption, which induces plasticization and softening. In this study, we investigated the ductilization mechanism of PMMA by incorporating various metal salts with different cations (Li<sup>+</sup> and Mg<sup>2+</sup>) and controlling water absorption through hygroscopic interactions. A nonequilibrium constitutive model is introduced, in which localized water domains around salt-rich regions gradually diffuse into the PMMA matrix during tensile deformation. The stress–strain behavior is described by combining rigid (dry) and soft (hydrated) matrix components, connected through an internal kinetic variable governed by the strain-dependent diffusion rate. The model successfully reproduces experimental tensile data and captures the transition from brittle to ductile behavior as a function of the moisture content. Notably, Mg salts exhibit stronger water binding and slower moisture redistribution than Li salts, resulting in distinct mechanical responses. These findings provide a mechanistic framework for tailoring the ductility of hygroscopic polymer systems via ion–water–polymer interactions.https://www.mdpi.com/1420-3049/30/12/2568poly(methyl methacrylate)mechanical propertieshygroscopicitymetal saltsnonequilibrium constitutive equation
spellingShingle Asae Ito
Naoki Uchida
Yusuke Hiejima
Koh-hei Nitta
Effects of Hydration on the Mechanical Properties of Salt-Doped Poly(methyl methacrylate)
Molecules
poly(methyl methacrylate)
mechanical properties
hygroscopicity
metal salts
nonequilibrium constitutive equation
title Effects of Hydration on the Mechanical Properties of Salt-Doped Poly(methyl methacrylate)
title_full Effects of Hydration on the Mechanical Properties of Salt-Doped Poly(methyl methacrylate)
title_fullStr Effects of Hydration on the Mechanical Properties of Salt-Doped Poly(methyl methacrylate)
title_full_unstemmed Effects of Hydration on the Mechanical Properties of Salt-Doped Poly(methyl methacrylate)
title_short Effects of Hydration on the Mechanical Properties of Salt-Doped Poly(methyl methacrylate)
title_sort effects of hydration on the mechanical properties of salt doped poly methyl methacrylate
topic poly(methyl methacrylate)
mechanical properties
hygroscopicity
metal salts
nonequilibrium constitutive equation
url https://www.mdpi.com/1420-3049/30/12/2568
work_keys_str_mv AT asaeito effectsofhydrationonthemechanicalpropertiesofsaltdopedpolymethylmethacrylate
AT naokiuchida effectsofhydrationonthemechanicalpropertiesofsaltdopedpolymethylmethacrylate
AT yusukehiejima effectsofhydrationonthemechanicalpropertiesofsaltdopedpolymethylmethacrylate
AT kohheinitta effectsofhydrationonthemechanicalpropertiesofsaltdopedpolymethylmethacrylate