Epoxy‐water interactions
01 Mar 1980-Polymer Engineering and Science (Society of Plastics Engineers, Inc.)-Vol. 20, Iss: 4, pp 315-319
TL;DR: In this article, the equilibrium sorption and diffusion of water in a high Tg epoxy was examined using various analytical techniques including differential scanning calorimetry, infrared spectroscopy, electron microscopy and nuclear magnetic resonance.
Abstract: It has been shown that sorbed moisture plasticizes epoxy resins with a resultant depression in the glass transition temperature of the polymer. The nature of the epoxy-water interaction still requires further investigation. The equilibrium sorption and diffusion of water in a high Tg epoxy is examined. Other analytical techniques including differential scanning calorimetry, infrared spectroscopy, electron microscopy and nuclear magnetic resonance are applied to the system. Experimental results suggest that the sorbed water at low concentrations is strongly localized at specific segments or groups in the polymer. Discussion is given relative to the structure-properties of the epoxy and its possible correlation to the experimental data obtained.
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TL;DR: In this paper, the authors assessed the nature of sorbed water and the related hygrothermal effects in epoxy resins and found that water molecules bind with epoxy resin through hydrogen bonding.
550 citations
TL;DR: The extensive amount of water sorption in the current hydrophilic dental resins is a cause of concern and may affect the mechanical stability of these resins and favor the rapid and catastrophic degradation of resin-dentin bonds.
507 citations
Cites background from "Epoxy‐water interactions"
...In contrast, the water molecules that attach to the polymer chain via hydrogen bonding, referred to as “bound” molecules, disrupt the interchain hydrogen bonding, induce swelling and plasticize the polymer [18,19]....
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TL;DR: In this article, three epoxy systems (DGEBA+mPDA, TGDDM+DDS, and Fiberite 934TM) were used to investigate glass transition temperature variation of epoxy under hygrothermal environment exposure.
352 citations
TL;DR: In this article, the characteristics of water sorption and diffusion in an amine-cured epoxy system based on tetraglycidyl diaminodiphenylmethane and a novolac glycidyl ether resin were studied as a function both of the polymer microstructure, known from previous works, and the temperature.
Abstract: The characteristics of sorption and diffusion of water in an amine-cured epoxy system based on tetraglycidyl diaminodiphenylmethane and a novolac glycidyl ether resin were studied as a function both of the polymer microstructure, known from previous works, and the temperature. Water-sorption experiments and dynamic mechanical analysis (DMA) were performed. Tensile stress–strain and Rockwell hardness tests were conducted to investigate the effects of absorbed water on the mechanical properties of the material. Competing effects of the sorption of water in the free volume and of strong interactions between water molecules and polar groups of the network were used to explain the diffusional behavior observed, which followed Fick's second law. DMA analysis seemed to be sensitive to the water effects and the viscoelastic behavior was related both to the water-sorption processes and to the microstructure of the system. An important impact of water uptake on the tensile properties at break was also appreciated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 71–80, 2001
298 citations
TL;DR: In this article, the epoxy-amine stoichiometry and the resulting microstructure of an epoxy system is studied as a function of epoxy amine stochastic properties and the relative importance of diffusion through the low-density and high-density microstructural phases.
Abstract: The moisture diffusion process of an epoxy system is studied as a function of epoxy-amine stoichiometry and the resulting microstructure. Differences in diffusion behavior are related to the relative importance of diffusion through the low-density and high-density microstructural phases for different stoichiometries. Also, changes in saturation level with stoichiometry are explained by competing effects of free volume versus the content of the low-density phase. Increasing the humidity level causes a corresponding increase in saturation level, while increasing the temperature causes more pronounced non-Fickian behavior. The effects of absorbed moisture on the thermomechanical properties of the epoxies are also investigated. Reductions in the glass transition temperature, Tg, and moisture-induced swelling strains are measured after exposure of samples to the three conditioning environments. Moisture-induced swelling strains increase with increasing moisture content. The reductions in Tg range from 5 to 20°C and are generally larger for amine-rich samples than for epoxy-rich and stoichiometric samples. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 787–798, 1999
275 citations
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24,580 citations
288 citations
TL;DR: In this paper, the activation energy for specific conduction was calculated for poly(2-hydroxyethyl methacrylate) (PHEMA) and three classes of water may exist in certain hydrogels.
160 citations
TL;DR: In this paper, the state of knowledge of the basic factors that control the durability of epoxies in service environments is reviewed, and the effect of fabrication and environmental factors and their complex interactions on the formation of permanent damage regions are discussed.
Abstract: : This report reviews the state of knowledge of the basic factors that control the durability of epoxies in service environments. The structure-property relations of amine (diethylene triamine, DETA)-cured bisphenol-A-diglycidyl ether (DGEBA) and amine (diaminodiphenyl sulfone, DDS)-cured tetraglycidyl 4,4'diaminodiphenyl methane (TGDDM) epoxies, the effects of sorbed moisture, and the fabrication and environmental factors that control the durability of epoxies are reviewed. The modes of deformation and failure of these materials, which occur primarily by crazing, are controlled by their network structure and microvoid characteristics. The pertinent, basic, physical phenonema induced and/or modified by sorbed moisture that affect the durability of epoxies are reviewed. These include the plasticization, swelling stresses, and modification of the crazing process in epoxies caused by sorbed moisture together with the diffusion characteristics of moisture in these materials. The durability of epoxies in service environments are discussed in terms of the structure-property relations of epoxies, the effect of fabrication and environmental factors and their complex interactions on the formation of permanent damage regions. (Author)
99 citations