Effect of curing temperature conditions on glass transition temperature values of epoxy polymer used for wet lay-up applications

Michel, Marie; Ferrier, Emmanuel

doi:10.1016/j.conbuildmat.2019.117206

Cited by 63 publications

(27 citation statements)

References 25 publications

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“…The performance of the NSM strengthening system relies on the bond capacity of the joint between concrete and FRP material, which in turn depends on the properties of the adhesive (usually epoxy resin), among other parameters. Typically, epoxy adhesives can be affected by temperature, as near or beyond the glass transition temperature ( T g ), their mechanical properties may change [ 4 , 5 , 6 , 7 ]. This may lead to a decrease of its performance and premature debonding and therefore to a not complete exploitation of the strengthening system.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Effect of High Service Temperature on the Flexural Performance of Near-Surface Mounted (NSM) Carbon Fiber-Reinforced Polymer (CFRP)-Strengthened Concrete Beams

et al. 2021

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This paper presents a study of the effect of high service temperature (near or beyond glass transition temperature (Tg) of structural epoxy adhesive) on the behavior of near-surface mounted (NSM) carbon fiber-reinforced polymer (CFRP)-strengthened reinforced concrete (RC) beams. The study includes experimental work as well as analytical and numerical analysis. To this end, fourteen beams have been tested up to failure in two different series. In series 1, specimens with three different CFRP areas have been tested at two different temperatures (i.e., 20 and 40 °C). In series 2, and with the aim of evaluating the effect of higher temperatures, only one CFRP area was tested under four different temperatures (i.e., 20, 60, 70, and 85 °C). Experimental results are evaluated in terms of load–deflections, failure modes, and bond performance. Furthermore, the experimental load–deflection curves are satisfactorily compared to both analytical predictions and finite element (FE) numerical simulations. In both cases, shrinkage and temperature effects on the short-term response of flexural elements have been accounted for. No significant reduction in stiffness and ultimate load was observed for specimens being tested up to 60 °C (in the range of epoxy Tg), showing FRP rupture failure in all of them. For specimens under 70 and 85 °C, the failure mode changed from FRP rupture to FRP end debonding and concrete crushing, respectively.

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Section: Introductionmentioning

confidence: 99%

Experimental Study of the Effect of High Service Temperature on the Flexural Performance of Near-Surface Mounted (NSM) Carbon Fiber-Reinforced Polymer (CFRP)-Strengthened Concrete Beams

et al. 2021

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“…The popularity of the thermoset composites in the form of laminates reinforced with long fibers is due to the possibility of producing high mechanical performance products without the necessity of expensive technological equipment use. The hand wet lay-up method, vacuum-assisted resin transfer molding (VARTM), or resin infusion allows obtaining thinwalled composite structures with good quality and relatively low amount of structural defects [6,7].…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of the Reinforcement Type Effect on the Thermomechanical Properties and Burning of Epoxy-Based Composites

et al. 2021

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Aramid (AF), glass (GF), carbon (CF), basalt (BF), and flax (FF) fibers in the form of fabrics were used to produce the composites by hand-lay up method. The use of fabrics of similar grammage for composites’ manufacturing allowed for a comprehensive comparison of the properties of the final products. The most important task was to prepare a complex setup of mechanical and thermomechanical properties, supplemented by fire behavior analysis, and discuss both characteristics in their application range. The mechanical properties were investigated using tensile and flexural tests, as well as impact strength measurement. The investigation was improved by assessing thermomechanical properties under dynamic deformation conditions (dynamic mechanical–thermal analysis (DMTA)). All products were subjected to a fire test carried out using a cone calorimeter (CC).

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“…Using ‘difunctional’ diepoxy compounds and “tetrafunctional” primary diamine compounds, the curing reaction of the polymer matrix yields crosslinked polymer networks. In order to provide identical curing conditions for all formulations [ 31 ], an unusually high curing temperature of 150 °C needed to be chosen because of the melting point of DAN. The curing reaction itself ( Figure 3 ) involves the nucleophilic attack of the nitrogen atom on one of the α-carbon atoms of the epoxide ring, subsequent opening of the epoxide ring, and proton exchange among the ammonium group and the oxygen anion [ 32 ].…”

Section: Resultsmentioning

confidence: 99%

Temperature-Triggered/Switchable Thermal Conductivity of Epoxy Resins

et al. 2020

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The pronouncedly low thermal conductivity of polymers in the range of 0.1–0.2 W m−1 K−1 is a limiting factor for their application as an insulating layer in microelectronics that exhibit continuously higher power-to-volume ratios. Two strategies can be applied to increase the thermal conductivity of polymers; that is, compounding with thermally conductive inorganic materials as well as blending with aromatic units arranged by the principle of π-π stacking. In this study, both strategies were investigated and compared on the example of epoxy-amine resins of bisphenol A diglycidyl ether (BADGE) and 1,2,7,8-diepoxyoctane (DEO), respectively. These two diepoxy compounds were cured with mixtures of the diamines isophorone diamine (IPDA) and o-dianisidine (DAN). The epoxy-amine resins were cured without filler and with 5 wt.-% of SiO2 nanoparticles. Enhanced thermal conductivity in the range of 0.4 W·m−1·K−1 was observed exclusively in DEO-based polymer networks that were cured with DAN (and do not contain SiO2 fillers). This observation is argued to originate from π-π stacking of the aromatic units of DAN enabled by the higher flexibility of the aliphatic carbon chain of DEO compared with that of BADGE. The enhanced thermal conductivity occurs only at temperatures above the glass-transition point and only if no inorganic fillers, which disrupt the π-π stacking of the aromatic groups, are present. In summary, it can be argued that the bisphenol-free epoxy-amine resin with an epoxy compound derivable from natural resources shows favorably higher thermal conductivity in comparison with the petrol-based bisphenol-based epoxy/amine resins.

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Effect of curing temperature conditions on glass transition temperature values of epoxy polymer used for wet lay-up applications

Cited by 63 publications

References 25 publications

Experimental Study of the Effect of High Service Temperature on the Flexural Performance of Near-Surface Mounted (NSM) Carbon Fiber-Reinforced Polymer (CFRP)-Strengthened Concrete Beams

Experimental Study of the Effect of High Service Temperature on the Flexural Performance of Near-Surface Mounted (NSM) Carbon Fiber-Reinforced Polymer (CFRP)-Strengthened Concrete Beams

Comparative Study of the Reinforcement Type Effect on the Thermomechanical Properties and Burning of Epoxy-Based Composites

Temperature-Triggered/Switchable Thermal Conductivity of Epoxy Resins

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