Oxidation induced shrinkage for thermally aged epoxy networks

Decelle, J.; Huet, Nathalie; Bellenger, V.

doi:10.1016/s0141-3910(03)00094-6

Cited by 105 publications

(63 citation statements)

References 6 publications

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“…Some recurrent features of aging behavior are: the eventual occurrence of postcure reactions coexisting with oxidation [13,14], carbonyl growth [15,16,10,17], and chain scission [18,19]. This latter process is especially important owing to its role in polymer embrittlement [20].…”

Section: Introductionmentioning

confidence: 99%

Thermo-oxidative aging of epoxy coating systems

Zahra

Fayolle

Kuntz³

et al. 2014

Progress in Organic Coatings

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. a b s t r a c tThe thermo-oxidative behavior of unformulated (unfilled) samples of epoxy coatings has been studied at five temperatures ranging from 70• C to 150• C. Two epoxy networks based on diglycidyl ether of bisphenol A (DGEBA), respectively, cured by jeffamine (POPA) or polyamidoamine (PAA) were compared. Infrared spectrophotometry (IR), differential scanning (DSC) and sol-gel analysis (SGA) were used to monitor structural changes.Thermal oxidation leads to carbonyl and amide formation in both systems. POPA systems appear more sensitive to oxidation than PAA ones. Thermal oxidation leads to predominant chain scission as evidenced by the decrease of glass transition temperatures (T g ) and increase of sol fraction.

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Section: Introductionmentioning

confidence: 99%

Thermo-oxidative aging of epoxy coating systems

Zahra

Fayolle

Kuntz³

et al. 2014

Progress in Organic Coatings

View full text Add to dashboard Cite

show abstract

“…There is large amount of literature works devoted to the thermal degradation mechanisms and kinetics of epoxy matrices showing that oxidation is clearly the predominant ageing process [1][2][3][4]. A key feature of such process is that degradation is non-uniform in the sample thickness because oxidation kinetics is diffusion controlled.…”

Section: Introductionmentioning

confidence: 99%

“…A key feature of such process is that degradation is non-uniform in the sample thickness because oxidation kinetics is diffusion controlled. A non-empirical kinetic model has been derived from a realistic oxidation mechanistic scheme for epoxy matrices in order to access the spatial distribution (in the sample thickness) of structural changes at the molecular scale as a function of exposure time [1][2][3][4]. This mechanistic scheme can be summarized as follows:…”

Section: Introductionmentioning

confidence: 99%

Oxidation induced changes in viscoelastic properties of a thermostable epoxy matrix

2013

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. AbstractThe thermal ageing of a neat epoxy matrix has been studied at 200°C in air by three complementary analytical techniques: optical microscopy, mechanical spectrometry and nanoindentation. Thermal oxidation is restricted in a superficial layer of about 195 µm of maximal thickness. It consists in a predominant chain scission process involving, in particular, chemical groups whose β motions have the highest degree of cooperativity and thus, are responsible for the high temperature side of β dissipation band. As a result, chain scissions decrease catastrophically the glass transition temperature, but also increase significantly the storage modulus at glassy plateau between T β and T α . This phenomenon is called "internal antiplasticization". Starting from these observations, the Di Marzio and Gilbert's theories have been used in order to establish relationships between the glass transition temperature and number of chain scissions, and between the storage modulus and β transition activity respectively. The challenge is now to establish a relationship between the transition activity and the concentration of the corresponding chemical groups.

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“…Also, the interaction between oxidation and decomposition, if any, was assumed insignificant, and the difference between weight loss in air and argon was completely due to oxidation. The superficial nature of oxidation and the accompanying volumetric polymer decomposition were reported in the literature [3,12,16].…”

Section: Resultsmentioning

confidence: 91%

“…Weight loss, density increase, and volumetric shrinkage are observed during the propagation of the oxidized layer. Due to volumetric shrinkage, strain and stress fields are built up, leading to matrix cracking [3]. Although polymer oxidation is a superficial phenomenon, decomposition reactions are associated with a volumetric degassing of chain cleavage products.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic oxidation prediction using optimized weight loss behavior of bismaleimide composites

2016

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High-temperature polymer matrix composites are susceptible to thermo-oxidation, which accelerates their degradation and reduces the service life. This work presents the viability of using experimental weight loss for modeling the spatial distribution of oxidation when the oxidized polymer matrix is not discernible due to cracking. The oxidized layer thickness and weight loss were predicted at a microscale level by implementing a volumetric integral in finite element analysis and scaled to a macroscale level by respective area ratios. Weight loss was shown to have a spatial distribution following the three-zone model. The proportionality parameter was optimized by fitting the scaled finite element predictions to the experimental results using artificial neural networks and a generalized pattern search algorithm. Aging experiments have been conducted at the operating temperature range of BMIs, 176.67°C (350°F) and 200°C (392°F). Optical dark field images were acquired to monitor longitudinal and transverse oxidation. Microscale simulations were conducted using representative volume elements utilizing COMSOL Multiphysics. A novel characteristic index for describing the completely oxidized matrix was the weight loss per unit volume that equals 0.44 mg/lm 3 as shown by spatial distribution simulations. The orthotropic diffusivity resulted in a higher degree of anisotropy in the oxidized thickness compared to the weight loss %. At the representative volume element scale, the oxidized layer thickness simulations showed a higher degree of non-linearity at higher temperatures stemming from the cracking effect.

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Oxidation induced shrinkage for thermally aged epoxy networks

Cited by 105 publications

References 6 publications

Thermo-oxidative aging of epoxy coating systems

Thermo-oxidative aging of epoxy coating systems

Oxidation induced changes in viscoelastic properties of a thermostable epoxy matrix

Anisotropic oxidation prediction using optimized weight loss behavior of bismaleimide composites

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