Local dynamics and molecular origin of polymer network-water interactions as studied by broadband dielectric relaxation spectroscopy, FTIR, and molecular simulations

Jovan Mijovic, Hua Zhang

Research output: Contribution to journalArticle

Abstract

An investigation was carried out of the molecular interactions and local relaxation dynamics in glassy polymer networks exposed to moisture. Stoichiometric and off-stoichiometric mixtures of the diglycidyl ether of bisphenol A (DGEBA) and diethylene triamine (DETA) were prepared, cured, and investigated. The physical and the chemical nature of the interactions between the network and the absorbed moisture were studied by broadband dielectric relaxation spectroscopy (DRS), Fourier transform near-infrared (FT-NIR) spectroscopy, and molecular simulations. Dry networks are characterized by two Arrhenius-like local relaxations: the β process, associated with hydroxyl groups, and the γ process, associated with primary and secondary amine, and glycidyl ether groups. Absorbed water interacts with the network and affects the dynamics of β and γ processes. FT-NIR spectra reveal the presence of three forms of water molecules, differing in the number of hydrogen atoms (0, 1, or 2) that participate in hydrogen bonds. The relative ratio of each form to the total absorbed water was calculated from the NIR data and from molecular simulations. An excellent agreement between those two techniques was observed.

Original languageEnglish (US)
Pages (from-to)1279-1288
Number of pages10
JournalMacromolecules
Volume36
Issue number4
DOIs
StatePublished - Feb 25 2003

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Dielectric relaxation
Polymers
Spectroscopy
Water
Ethers
Fourier transforms
Moisture
Near infrared spectroscopy
Molecular interactions
Hydroxyl Radical
Amines
Hydrogen
Hydrogen bonds
Infrared radiation
Atoms
Molecules

ASJC Scopus subject areas

  • Materials Chemistry

Cite this

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title = "Local dynamics and molecular origin of polymer network-water interactions as studied by broadband dielectric relaxation spectroscopy, FTIR, and molecular simulations",
abstract = "An investigation was carried out of the molecular interactions and local relaxation dynamics in glassy polymer networks exposed to moisture. Stoichiometric and off-stoichiometric mixtures of the diglycidyl ether of bisphenol A (DGEBA) and diethylene triamine (DETA) were prepared, cured, and investigated. The physical and the chemical nature of the interactions between the network and the absorbed moisture were studied by broadband dielectric relaxation spectroscopy (DRS), Fourier transform near-infrared (FT-NIR) spectroscopy, and molecular simulations. Dry networks are characterized by two Arrhenius-like local relaxations: the β process, associated with hydroxyl groups, and the γ process, associated with primary and secondary amine, and glycidyl ether groups. Absorbed water interacts with the network and affects the dynamics of β and γ processes. FT-NIR spectra reveal the presence of three forms of water molecules, differing in the number of hydrogen atoms (0, 1, or 2) that participate in hydrogen bonds. The relative ratio of each form to the total absorbed water was calculated from the NIR data and from molecular simulations. An excellent agreement between those two techniques was observed.",
author = "Jovan Mijovic and Hua Zhang",
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N2 - An investigation was carried out of the molecular interactions and local relaxation dynamics in glassy polymer networks exposed to moisture. Stoichiometric and off-stoichiometric mixtures of the diglycidyl ether of bisphenol A (DGEBA) and diethylene triamine (DETA) were prepared, cured, and investigated. The physical and the chemical nature of the interactions between the network and the absorbed moisture were studied by broadband dielectric relaxation spectroscopy (DRS), Fourier transform near-infrared (FT-NIR) spectroscopy, and molecular simulations. Dry networks are characterized by two Arrhenius-like local relaxations: the β process, associated with hydroxyl groups, and the γ process, associated with primary and secondary amine, and glycidyl ether groups. Absorbed water interacts with the network and affects the dynamics of β and γ processes. FT-NIR spectra reveal the presence of three forms of water molecules, differing in the number of hydrogen atoms (0, 1, or 2) that participate in hydrogen bonds. The relative ratio of each form to the total absorbed water was calculated from the NIR data and from molecular simulations. An excellent agreement between those two techniques was observed.

AB - An investigation was carried out of the molecular interactions and local relaxation dynamics in glassy polymer networks exposed to moisture. Stoichiometric and off-stoichiometric mixtures of the diglycidyl ether of bisphenol A (DGEBA) and diethylene triamine (DETA) were prepared, cured, and investigated. The physical and the chemical nature of the interactions between the network and the absorbed moisture were studied by broadband dielectric relaxation spectroscopy (DRS), Fourier transform near-infrared (FT-NIR) spectroscopy, and molecular simulations. Dry networks are characterized by two Arrhenius-like local relaxations: the β process, associated with hydroxyl groups, and the γ process, associated with primary and secondary amine, and glycidyl ether groups. Absorbed water interacts with the network and affects the dynamics of β and γ processes. FT-NIR spectra reveal the presence of three forms of water molecules, differing in the number of hydrogen atoms (0, 1, or 2) that participate in hydrogen bonds. The relative ratio of each form to the total absorbed water was calculated from the NIR data and from molecular simulations. An excellent agreement between those two techniques was observed.

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