Modeling of interphase in composite materials: Characterization of epoxy resin/aminosilane system

Sérier, Aîcha; Pascault, J. P.; My, Lam Thanh

doi:10.1002/masy.19890250109

Cited by 3 publications

(2 citation statements)

References 6 publications

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“…Its interaction with water can, indeed, play an important role in composite durability. It is well recognized that the interphase displays a more or less diffuse multi-layer structure [52][53][54][55][56]. In glass-polymer composites with silanes as coupling agents for instance, one expects the presence of three concentric layers:…”

Section: Interfacial Water Absorptionmentioning

confidence: 99%

“…The extension of the latter depends on the diffusion conditions of the monomers used for crosslinking layer (II) [53]. Since, generally, the group -Y used to react with the coupling agent is also reactive in polymer crosslinking, one can expect a local perturbation of the polymer structure resulting from the local deficit of -Y groups [56,147]. This interphase structure has been described by various authors, among whom Ishida [148,149] has been a prominent contribution.…”

Section: Hydrolytic Processes In the Interfacial Regionmentioning

confidence: 99%

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Humid Ageing of Organic Matrix Composites

Colin

Verdú

2013

Solid Mechanics and Its Applications

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In this chapter, several aspects of the ageing phenomena induced by water in organic matrix composites are examined, essentially from the physicochemical point of view. It is first important to recognize that there are two main categories of humid ageing. First there are physical processes, mainly linked to the stress state induced by matrix swelling and sometimes matrix plasticization. This kind of ageing can occur in matrices of relatively high hydrophilicity (affinity with water). Highly crosslinked amine cured epoxies are typical examples of this behavior. The second category of humid ageing involves a chemical reaction (hydrolysis) between the material and water. Unsaturated polyesters are typical examples of this category. They display a low to moderate hydrophilicity, swelling and plasticization have minor effects, but hydrolysis induces a deep polymer embrittlement and, eventually, osmotic cracking. Whatever the ageing mechanism, it needs the water to penetrate into the material and depends on the water concentration and its distribution in the sample thickness. This is the reason why the first and second sections are respectively dedicated to water solubility and diffusivity in matrices, interphases and composites. In each case, the elementary processes are distinguished, to examine the effects of temperature and stress state and to establish structure-property relationships. It is shown that, in most of these aspects, research remains largely open. The last section is devoted to hydrolysis, its kinetic modeling, including the case of diffusion controlled hydrolysis, and its consequences on polymer properties. Structure reactivity relationships are briefly presented. The very important case of osmotic cracking, which can be considered as a consequence of hydrolysis, is also examined.

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Section: Interfacial Water Absorptionmentioning

confidence: 99%

Section: Hydrolytic Processes In the Interfacial Regionmentioning

confidence: 99%

Humid Ageing of Organic Matrix Composites

Colin

Verdú

2013

Solid Mechanics and Its Applications

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Hydrolytic aging of polysiloxane networks modeling the glass fiber epoxy‐amine interphase

et al. 1999

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It has previously been shown that polycondensates of trialkoxysilanes (AlkO)3SiR could chemically simulate coupling agent layers located at the interphase of amine‐crosslinked epoxy/glass fiber composites (1) and that a humid environment modifies the degree of condensation of the network. Although it is generally believed that water will inevitably hydrolyze the polysiloxane structure and destroy the interphase (2), the authors have demonstrated that the siloxane links of the network evolve toward an equilibrium state. This state depends on the chemical structure of the organic chain that can react with the matrix. For example, in the case of aminopropyltriethoxysilane, the siloxane equilibrium concentration is low enough to allow total hydrolysis of the polymer. Conversely, propylsilane network stability could be explained by a very high siloxane equilibrium concentration. In this article, one of the previously studied systems has been selected: GPS (glycidylpropylsilane), in which the coupling function is an epoxide group (glycidyl). In an epoxy/glass fiber composite, this group is expected to react with an amine group belonging to the epoxy network. Aniline has been used here to model the GPS‐epoxy network bonding. This reaction modifies the chemical nature of the organic chain branched on the silicon and then potentially displaces the siloxane equilibrium. A gravimetric method, size exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FTIR), 29Si nuclear magnetic resonance (NMR), and 13C NMR have been used. The results are that, when exposed to hot water, the GPS and the GPS‐aniline networks evolve contradictorily. Although GPS tends to hydrolysis, GPS‐aniline tends to condensation. This article analyzes the compatibility of the different behaviors with the simple kinetic model reported in a previous paper (1) and the importance of this phenomenon concerning the aging of the glass/matrix interphase of composite materials.

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Reactions in aminosilane‐epoxy prepolymer systems. II. Reactions of alkoxysilane groups with or without the presence of water

Sérier

Pascault

Lam

1991

J. Polym. Sci. A Polym. Chem.

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SYNOPSISThe hydrolysis and reactions of alkoxy silane groups have been studied on a model compound ( T A ) prepared from 2 mol of phenyl glycidyl ether and 1 mol of aminopropyl triethoxy silane. At low (40°C) and high (140°C) temperatures, the monomer conversion and the evolution of the molecular mass are followed by size exclusion chromatography (SEC) .During the same reaction time, the evolution of the functional groups, hydroxyl CH-OH, ethoxy -O-CC2H5, and siloxane Si-0-Si, is observed by FTIR spectroscopy. Without the presence of water, reactions between hydroxyl and ethoxy silane lead to gelation at the end of the reaction. A by-product, probably a cyclic tetramer is also formed. After the hydrolysis, the reaction of the model compound is quite different. The product of reaction is always soluble, even after a treatment a t high temperatures, and the evolution of the molecular mass versus the reaction time seems to correspond to the condensation giving a dead cyclic tetramer. From this study it is evident that the curing cycle has a great influence on the properties of the interface of a composite based on a epoxy matrix.

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Modeling of interphase in composite materials: Characterization of epoxy resin/aminosilane system

Cited by 3 publications

References 6 publications

Humid Ageing of Organic Matrix Composites

Humid Ageing of Organic Matrix Composites

Hydrolytic aging of polysiloxane networks modeling the glass fiber epoxy‐amine interphase

Reactions in aminosilane‐epoxy prepolymer systems. II. Reactions of alkoxysilane groups with or without the presence of water

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