Dynamic mechanical response of model epoxy networks in the glassy state

Cukierman, Serge; Halary, Jean Louis; Monnerie, L.

doi:10.1002/pen.760312006

Cited by 71 publications

(52 citation statements)

References 18 publications

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“…The influence of network architecture on the properties of the matrices has been clarified by using series of model systems, designed to present a systematic variation of the network rigidity while keeping the crosslink density constant, and vice versa. 4 -7 Thus, unambiguous results were obtained dealing with the glass transition temperature T g , 5,[7][8][9] , the free volume, 10 the secondary relaxation ␤, 5,11,12 and the antiplasticization phenomenon. 13,14 In the case of composites, additional pending questions refer to the interaction between matrix and fiber.…”

Section: Introductionmentioning

confidence: 82%

Relationships between thermally induced residual stresses and architecture of epoxy-amine model networks

Bauchiere

Halary

Monnerie

et al. 2000

J. Appl. Polym. Sci.

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ABSTRACT:The capability of epoxy-amine resins to develop residual stresses was studied as a function of temperature and network architecture. These residual stresses were induced while cooling epoxy-glass bilayers from temperatures higher than the network glass transition temperature, T g . This behavior was the result of the marked differences (␣ r Ϫ ␣ g ), in linear thermal expansion coefficient of the two components, as evidenced by the measurement of ␣ r for the epoxy networks under study. Various network architectures were selected, resulting from variation of (1) the chemical nature of both epoxide and curing agent, (2) the nature and relative amount of the chain-extensor agent, and (3) the stoichiometric ratio. Three ranges of cooling temperature were observed systematically: first, the range of temperatures above T g , where no stress has been detected, then an intermediate temperature range (from T g to T*), where stresses develop quite slowly, and finally, the low temperature range (T Ͻ T*), where a linear increase in stress accompanies the decrease of temperature. The two latter regimes were quantitatively characterized by the extent, T g Ϫ T*, of the first one and by the slope, SDR, of the second one. T g Ϫ T* values were shown to be governed by the T g of the network: the higher the T g , the larger the gap between T g and T*. This result was interpreted by accounting for the variation of relaxation rate at T g from one network to the other. It was also shown that a semiempirical relationship holds between SDR and T g : SDR decreases monotonically as T g increases. By inspecting the effects of network architecture in more details, it turned out that SDR is governed by the Young's moduli, E r (T Ϫ T g ), of the epoxy resins in the glassy state: the lower E r (T Ϫ T g ), the lower SDR in a series of homologous networks. As E r (T Ϫ T g ) values are known to be related to the characteristics of the secondary relaxation ␤, which depends, in turn, on crosslink density, SDR values were finally connected to the amplitude of the ␤ relaxation processes. This finding was corroborated by the measurements on an antiplasticized dense network. Finally, data relative to thermoplastic-filled networks showed that the addition of thermoplastic reduces the development of residual stresses, whatever the system, is homogeneous or biphasic.

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Section: Introductionmentioning

confidence: 82%

Relationships between thermally induced residual stresses and architecture of epoxy-amine model networks

Bauchiere

Halary

Monnerie

et al. 2000

J. Appl. Polym. Sci.

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“…Nevertheless, at a lower temperature, especially near room temperature range, the higher E' value of DEU -EP/DDM likely suggests that the stronger interaction in the cured network. This interaction is probably owing to the more regular packaging of the aromatic moieties in the DEU-EP/DDM epoxy network (Scheme 4) resulting optimally compacted configuration of the network chains, which creates stronger cohesive energy (e.g., π-π stacking among the aromatic rings) in the network at the glassy state [44][45][46]. However, this non-covalent becomes very weak, once the pxylene ether bonds possess enough kinetic energy to overcome the energetic barrier for their motions at a higher temperature.…”

Section: Figmentioning

confidence: 99%

A sustainable, eugenol-derived epoxy resin with high biobased content, modulus, hardness and low flammability: Synthesis, curing kinetics and structure–property relationship

Wan

Gan

et al. 2016

Chemical Engineering Journal

237

138

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Abstract:To develop functional sustainable epoxy resins, we report a novel epoxy resin (DEU-EP) with high net biobased content (70.2 wt%) derived from renewable eugenol. We comparatively study DEU-EP with a commercial bisphenol A epoxy resin (DGEBA) in the presence of a most representative aromatic diamine curing agent, 4,4'-diaminodiphenyl methane (DDM).Differential scanning calorimetry reveals that DEU-EP can be sufficiently cured by DDM at a slower rate than DGEBA. By applying an autocatalytic reaction model, we adequately simulate the curing rate of DEU-EP/DDM, and reveal its detailed kinetic mechanisms from model-free isoconversional analysis. Dynamic mechanical analysis shows that DEU-EP/DDM takes higher storage modulus up to ~97 o C than DGEBA/DDM with the glass temperature of 114 o C. Nanoindentation and thermogravimetric analysis demonstrate that compared with DGEBA/DDM, DEU-EP/DDM exhibits a 20%, 6.7% and 111% increase in Young's modulus, hardness and char yield, respectively. Microscale combustion calorimetry data show that DEU-EP/DDM expresses 55% and 38% lower heat release rate and total heat release than DGEBA/DDM, respectively.Macroscopically, the horizontal burning test approves DEU-EP/DDM can self-extinguish in a short time. Our results demonstrate that the eugenol building blocks and their arrangement greatly affect the cure behaviors of DEU-EP/DDM, and contribute significantly to its enhanced mechanical properties, high-temperature charring ability and chain motions at glass state, as well as the reduced flammability. To summarize, DEU-EP exhibits a high promise as a new sustainable epoxy monomer for fabricating high biobased content, high rigid and low flammable epoxy materials.

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“…The inversion can be related to the area of the β transition peak. The decrease of storage modulus is all the more important as the area of the peak is large, meaning that the number of hydroxypropylether sequences formed during the curing is high (Cukierman et al, 1991). At equal number of hydroxypropylether sequences, the mechanical losses are all the more important as the curing density is high, because of synergies in motions of dense systems (Cukierman et al, 1991).…”

Section: Molecular Mobilitymentioning

confidence: 99%

Relationship Between Epoxy Resin Properties and Weepage of Glass-Reinforced Filament-Wound Pipes

Maso¹,

Halary

Barrere-Tricca

2002

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Relation entre les propriétés de la résine et le phénomène de perlage de tubes composites verre-époxy -Afin de mieux comprendre le rôle de la matrice sur le phénomène de perlage de tubes composites, une démarche complète a été suivie, allant de la chimie des résines époxy à la mécanique de tubes composites sous pression, en passant par une étape intermédiaire de caractérisation d'échantillons composites plans. Quatre formulations présentant des propriétés mécaniques en traction très différentes ont été sélectionnées. L'étude de composites unidirectionnels plans a montré que la rupture en traction transverse se produit essentiellement par décohésion fibre/matrice. L'allongement à rupture des composites unidirectionnels plans en traction transverse est d'autant plus élevé que l'allongement de la résine à la rupture de l'interface fibre/matrice est grand. Des essais en pression interne avec effet de fond sur tubes composites bobinés à ± 55°ont montré que le perlage provient de la rupture des monocouches unidirectionnelles perpendiculairement aux fibres constituant la paroi du tube. Un critère simple de perlage a été proposé : le perlage apparaît pour une pression directement proportionnelle à l'allongement à rupture des composites unidirectionnels plans en traction transverse. La constante de proportionnalité dépend de la géométrie du tube. Abstract -Relationship between Epoxy Resin Properties and Weepage of Glass-Reinforced Filament-Wound Pipes -This study aims to understand the relationship between mechanical properties of a resin and weepage (loss of water tightness) of glass-reinforced filament-wound pipes. A three-

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Dynamic mechanical response of model epoxy networks in the glassy state

Cited by 71 publications

References 18 publications

Relationships between thermally induced residual stresses and architecture of epoxy-amine model networks

Relationships between thermally induced residual stresses and architecture of epoxy-amine model networks

A sustainable, eugenol-derived epoxy resin with high biobased content, modulus, hardness and low flammability: Synthesis, curing kinetics and structure–property relationship

Relationship Between Epoxy Resin Properties and Weepage of Glass-Reinforced Filament-Wound Pipes

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