Nature of the water-epoxy interaction

Jelinski, Lynn W.; Dumais, Jacques; Cholli, Ashok L.; Ellis, Thomas Sayers; Karasz, F. E.

doi:10.1021/ma00148a008

Cited by 105 publications

(70 citation statements)

References 7 publications

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“…This implies that the secondary network of hydrogen-bonding interactions formed among the hydroxyl groups of the epoxy network is not perturbed by the presence of absorbed water. A similar conclusion was reached by Jelinski et al 21 from quadrupole-echo NMR measurements.…”

supporting

confidence: 85%

Probing the molecular interactions in the diffusion of water through epoxy and epoxy–bismaleimide networks

Musto

Ragosta

Scarinzi

et al. 2002

J Polym Sci B Polym Phys

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ABSTRACT:Fourier transform infrared spectroscopy in the near-infrared (NIR) frequency range was used to investigate the molecular interactions occurring between absorbed water molecules and networks based on a tetrafunctional epoxy resin. One of these networks was a typical formulation containing 4,4Ј-diamino diphenylsulfone as a hardener, and the other was a modified resin containing 4,4Ј-bismaleimide-diphenylmethane (BMI) as a coreactive monomer. Molecular spectroscopy analysis confirmed the existence of mobile water localized into network defects (microvoids) that did not interact with the networks and water molecules bound to the networks through hydrogen-bonding interactions. In the BMI-containing system, the fraction of bound water decreased significantly with respect to the unmodified epoxy resin. This was a relevant result because the bound water was primarily responsible for the plasticization of the network and for the consequent worsening of mechanical performance. Water diffusion was investigated with gravimetric sorption measurements and time-resolved Fourier transform NIR spectroscopy measurements. These showed that the presence of BMI decreased the water uptake at equilibrium, enhanced the diffusivity, and reduced the activation energy for diffusion. A dual-mode model for diffusion was found to be suitable for accurately describing the mass-transport process in both investigated systems. The results of the model simulations allowed us to estimate the ratio of free and bound water, which was in good agreement with that obtained from the spectroscopic analysis.

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supporting

confidence: 85%

Probing the molecular interactions in the diffusion of water through epoxy and epoxy–bismaleimide networks

Musto

Ragosta

Scarinzi

et al. 2002

J Polym Sci B Polym Phys

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“…Polymers have a unique ability to absorb vapor molecules through the surface and into the bulk [190,191], a characteristic that is not present in most other inorganic materials. Water absorption is especially important in the plasticization of polymers [192] and the biocompatibility as it is the case in contact lenses [193]. Although vapor absorption studies are prevalent for polymeric materials, vapor adsorption onto polymer surfaces has been studied much less.…”

Section: Environmental Effect On Friction and Wear Of Polymeric Matermentioning

confidence: 99%

Vapors in the ambient—A complication in tribological studies or an engineering solution of tribological problems?

et al. 2015

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Tribology involves not only two-body contacts of two solid materials-a substrate and a counter-surface; it often involves three-body contacts whether the third body is intentionally introduced or inevitably added during the sliding or rubbing. The intentionally added third body could be lubricant oil or engineered nanomaterial used to mitigate the friction and wear of the sliding contact. The inevitably added third body could be wear debris created from the substrate or the counter surface during sliding. Even in the absence of any solid third-body between the sliding surfaces, molecular adsorption of water or organic vapors from the surrounding environment can dramatically alter the friction and wear behavior of solid surfaces tested in the absence of lubricant oils. This review article covers the last case: the effects of molecular adsorption on sliding solid surfaces both inevitably occurring due to the ambient test and intentionally introduced as a solution for engineering problems. We will review how adsorbed molecules can change the course of wear and friction, as well as the mechanical and chemical behavior, of a wide range of materials under sliding conditions.

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“…Considerable discussion and disagreement has occurred on the types of molecular environment of adsorbed water (bonded and nonbonded) and the types of absorption kinetics (Fickian or non-Fickian). [21][22][23][24][25][26][27][28][29][30] In contrast, the bulk of the industry testing has relied on the mechanical and fatigue (microcracking) effects on composite samples and has often used quite extreme conditions to accelerate changes. For example, the use of full water immersion at 708C, 908C, or even boiling water is common.…”

Section: Introductionmentioning

confidence: 99%

Accelerated ageing versus realistic ageing in aerospace composite materials. IV. Hot/wet ageing effects in a low temperature cure epoxy composite

Dao

Hodgkin

Krstina

et al. 2007

J of Applied Polymer Sci

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Samples of an aerospace grade carbon fiber epoxy composite (Hexcel, M20/IM7) were subject to long term (%1 year) hot/wet ageing and thermal spiking under a variety of humidity levels and temperature conditions related to ''in service'' conditions seen by military aircraft. Changes to the chemical and physicochemical structure of the composite were analyzed by a range of different techniques including gravimetric analysis, FTIR, and DMA to compare the effects of the various ageing conditions. The results indicated that the chemical effects of hot/wet and spiking conditions on this incompletely cured type of composite are very complex because of the variations in moisture levels and cure chemistry from the composite surface inwards as the resin ages under the different external environments. Physicochemical changes (such as T g ) and structural effects (such as microcracking) are similarly complex and dependent on composite thickness.

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Nature of the water-epoxy interaction

Cited by 105 publications

References 7 publications

Probing the molecular interactions in the diffusion of water through epoxy and epoxy–bismaleimide networks

Probing the molecular interactions in the diffusion of water through epoxy and epoxy–bismaleimide networks

Vapors in the ambient—A complication in tribological studies or an engineering solution of tribological problems?

Accelerated ageing versus realistic ageing in aerospace composite materials. IV. Hot/wet ageing effects in a low temperature cure epoxy composite

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