Failure of epoxies bonded assemblies: comparison of thermal and humid ageing

Delozanne, Justine; Desgardin, Nancy; Coulaud, Magali; Cuvillier, Nicolas; Richaud, Emmanuel

doi:10.1080/00218464.2018.1547198

Cited by 16 publications

(7 citation statements)

References 41 publications

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“…Epoxy materials are widely used in the marine domain as coatings [1,2], adhesives [3,4] and as a matrix for many composite materials [5][6][7][8]. Because long term durability is mandatory for structures used at sea for both ecological and economic reasons, the durability of epoxy polymers in a humid environment has been widely studied in the past [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Physical ageing of epoxy in a wet environment: Coupling between plasticization and physical ageing

Guen-Geffroy¹,

Gac²,

Habert³

et al. 2019

Polymer Degradation and Stability

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This paper shows how physical ageing and plasticization processes are coupled in an amine-based epoxy. The study combines several ageing conditions including thermal ageing in the dry state (from 40 to 60 °C), ageing in a humid environment (RH 50% and RH 75%) as well as immersion in seawater at several temperatures from 15 to 40 °C. First results are presented to highlight that the two processes (physical ageing and plasticization) both occur when the epoxy is immersed in water. A step-by-step approach is then used to evaluate how the plasticization process induced by the presence of water is affected by physical ageing and vice versa. It appears that the plasticization process, which leads to a large decrease in maximum stress under tensile loading, is not affected by physical ageing of the epoxy. The physical ageing mechanism is not affected by the presence of water in the polymer, i.e. the same increase in maximum tensile stress (26 MPa) is observed in air and in water. However, the kinetic rate of physical ageing is much faster in water due to the plasticization of the polymer. These effects must be considered when accelerated aging methods are applied. Highlights ► Plasticization process induced by water absorption is not greatly affected by physical ageing. ► Physical ageing process occurs in both dry and humid environments. ► Physical ageing is much faster in the presence of water (by a factor of 10).

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Section: Introductionmentioning

confidence: 99%

Physical ageing of epoxy in a wet environment: Coupling between plasticization and physical ageing

Guen-Geffroy¹,

Gac²,

Habert³

et al. 2019

Polymer Degradation and Stability

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“…In the field of epoxy adhesives used at high temperatures, mass loss seems correlated with the drop of adhesive strength [6]. In a recent work on titanium/epoxy/titanium bonded assemblies, microscopic analyses lead us to propose that thermal oxidation induced a cohesive failure of the epoxy-adhesive [7]. Such mechanisms of embrittlement seem to originate from the depletion of the b relaxation associated to plasticity and toughness in epoxy/diamine networks [8] i.e.…”

Section: Introductionmentioning

confidence: 99%

Thermal oxidation of aromatic epoxy-diamine networks

Delozanne

Desgardin

Cuvillier

et al. 2019

Polymer Degradation and Stability

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The thermal oxidation of DGEBA-DDS (bisphenol A diglycidyl ether þ 4,4 0-diaminodiphenyl sulfone) and TGMDA-DDS (4,4 0-methylenebis(N,N-diglycidylaniline) þ 4,4 0-diaminodiphenyl sulfone) was performed at 80, 120, and 200 C and was monitored by FTIR. Oxidation was shown to generate amides and carbonyls. Comparisons were done with model systems displaying some common reactive groups, which highlighted the predominating role of methylene in a position of ether in DGEBA-DDS and methylene in a position of nitrogen hold by TGMDA in TGMDA-DDS. The participation of CH 2 in a position of DDS hardener group seems to depend on the temperature and decrease when lowering it. The oxidation of such complex systems must hence be described by a co-oxidation model where each kind of reactive sites is described by its own set of kinetic constants.

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“…Li et al underlined that micron-sized CaCO 3 may have a negative impact on the mechanical performance of polymers [ 42 ]. Some researchers (e.g., Delozanne et al [ 27 ], Calvez et al [ 28 ], Bowditch [ 29 ], and others [ 7 , 16 , 23 , 24 ]) have reported that moisture in bulk epoxy compounds tends to migrate to the epoxy compound–substrate interface and decreases the adhesion force there. Sai Sravani et al also indicated that there was a decrease in tensile and flexural strength with the addition of filler material [ 48 ].…”

Section: Discussionmentioning

confidence: 99%

“…Works dealing with the analysis of the degradation process of epoxy compositions in various aqueous environments have previously been published [ 19 , 21 , 24 , 27 , 28 , 29 , 30 , 31 , 32 ]. In the work by Rudawska and Brunella [ 33 ], the effect of operating factors such as seasoning in water solution, containing iron sulfate, and the time of seasoning was investigated.…”

Section: Introductionmentioning

confidence: 99%

The Impact of the Acidic Environment on the Mechanical Properties of Epoxy Compounds in Different Conditions

Rudawska

2020

Polymers

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The aim of this work was to determine the impact of the acidic environment on the mechanical properties of two epoxy compounds in different conditions. The samples were made from the epoxy compounds composed of the epoxy resin (based on Bisphenol A), triethylenetetramine curing agent (unmodified compound), and calcium carbonate (CaCO3) (modified compound). The epoxy compound samples were seasoned for the following period of time (i.e., one week, one month, and three months). The environment was tap water and the acidic environment had three different concentrations of acetic acid (3%, 6%, and 9%). Strength tests of the epoxy compound samples were carried out in accordance with the ISO 604 standard. In the case of the modified composition, it is noted that the samples immersed in tap water were characterized by a higher strength than in acidic environments. A similar tendency was observed for unmodified compositions, although the differences were smaller than for the modified compositions. It was also noticed that the increase in the pH of the acidic solution in many analyzed cases contributed to the decrease in mechanical properties, although the immersion time in the acidic solution is important.

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Failure of epoxies bonded assemblies: comparison of thermal and humid ageing

Cited by 16 publications

References 41 publications

Physical ageing of epoxy in a wet environment: Coupling between plasticization and physical ageing

Physical ageing of epoxy in a wet environment: Coupling between plasticization and physical ageing

Thermal oxidation of aromatic epoxy-diamine networks

The Impact of the Acidic Environment on the Mechanical Properties of Epoxy Compounds in Different Conditions

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