A comparative study between epoxy/Titania micro‐ and nanoparticulate composites thermal and mechanical behavior by means of particle–matrix interphase considerations

Papanicolaou, George; Kostopoulos, V.; Kontaxis, Lykourgos C.; Kollia, Evgenia; Κοτρώτσος, Αθανάσιος

doi:10.1002/pen.24668

Cited by 11 publications

(6 citation statements)

References 69 publications

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“…For the displacement rates of 0.5 and 5 mm/min, an almost linear behavior can be observed; for the 10 and 50 mm/min displacement-rates, by increasing the filler-weight fraction, an initial increase in flexural modulus is observed, followed by a subsequent decrease of the flexural modulus for filler-weight fraction higher than 10%. This is a recurring behavior that is also observed and explained in Section 3.2 as well as in literature [30]. As already mentioned, the initial increase in flexural modulus is attributed to the matrix reinforcement provided by the TiO 2 microparticles.…”

Section: Displacement-rate Resultssupporting

confidence: 77%

“…On the contrary, nanoparticle TiO 2 composites do not exhibit a similar behavior to their micro-particulate counterparts. Initially, a decrease is observed in flexural modulus, which results in modulus values lower than this of the pure resin-a behavior previously encountered [30]. As the size of nanoparticles approaches, the molecular size of polymeric chains, the nanoparticles interfere with polymer macromolecules, delaying or even prohibiting the crosslinking mechanism between polymer chains to take place.…”

Section: Flexural Characterizationmentioning

confidence: 90%

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Experimental and Prediction Study of Displacement-Rate Effects on Flexural Behaviour in Nano and Micro TiO2 Particles-Epoxy Resin Composites

2019

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Epoxy resin composites with different weight fractions of TiO 2 microparticles (1%, 5%, 10%, 15%, 20%) and of TiO 2 nanoparticles (0.5%, 1%, 2%, 3%) were prepared. The particle size of the nanoparticles was averaged around 21 nm while the particle size of the micro TiO 2 particles was averaged around 0.2 µm. The morphology of the manufactured particulate composites was studied by means of scanning electron microscopy (SEM). The mechanical properties of both nanocomposites (21 nm) and microcomposites (0.2 µm) were investigated and compared through flexural testing. Furthermore, the effect of displacement-rate on the viscoelastic behavior of composite materials was investigated. The flexural tests were carried out at different filler weight fractions and different displacement-rates (0.5, 5, 10, 50 mm/min). The influence of TiO 2 micro-and nanoparticles on the mechanical response of the manufactured composites was studied. For micro TiO 2 composites, a maximum increase in flexural modulus on the order of 23% was achieved, while, in the nanocomposites, plastification of the epoxy matrix due to the presence of TiO 2 nanoparticles was observed. Both behaviors were predicted by the Property Prediction Model (PPM), and a fair agreement between experimental results and theoretical predictions was observed.Polymers 2020, 12, 22 2 of 13 in improving the mechanical properties of the composite. The lower the filler diameter, the higher the filler surface/contact area is. Thus, in case of micron sized particles, the size of the low-density interfacial region of the pure polymer surrounding the inclusion is higher, so that the contribution of the filler is reduced, concluding that the mechanical properties of the composite will not be improved that much [6]. On the contrary, the nanoparticles can fill up the weak regions within the epoxy resin, and thus increasing the filler-matrix interaction force. The increase of the extent interfacial region can significantly improve the mechanical properties of the epoxy/nanocomposite. However, the nanoparticles have a difficulty to disperse into the matrix, so it is crucial to find the proper manufacturing technique to improve particle dispersion within the matrix material. A technique that is commonly applied is the ultrasonic homogenization; however, as every technique has its disadvantages. More precisely, this technique decreases the gelling time of the epoxy resin [7][8][9][10][11].The mechanical response of particulate reinforced composites also depends on the rate of deformation. It was found that particulates increase the strain rate sensitivity concerning tensile modulus, but this sensitivity decreases when measuring yield strength [12]. The effect of strain rate on the flexural properties of some polymer matrix composites has been studied and, as it was found, the flexural modulus and flexural strength both increase linearly with the logarithm of the strain rate [13]. Furthermore, the strain-rate sensitivity seems to be slightly more pronounced in shear than in tension and comp...

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Section: Displacement-rate Resultssupporting

confidence: 77%

Section: Flexural Characterizationmentioning

confidence: 90%

Experimental and Prediction Study of Displacement-Rate Effects on Flexural Behaviour in Nano and Micro TiO2 Particles-Epoxy Resin Composites

2019

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“…The decrease in flexural strength can be attributed to the relatively poor interaction of microparticles and the polymer matrix. Because of that reason, the crosslinking is delayed, [37] and the energy requirement for crack initiation and growth reduces. [27] Moreover, the agglomeration at higher filler content might be due to the weaker Van der Waals bonds, as also stated by Khan et al [38] Figure 10 shows the fracture surface of Charpy impact test specimens.…”

Section: Scanned Electron Microscopy (Sem)mentioning

confidence: 99%

“…As the filler content increased, the T g values decreased, and the rate of decrease is higher for 4% MgO addition. Papanicolaou et al [37] indicated the reason as matrix plastification effect due to filler dispersion. Because the microparticles interfere in the molecular form of the polymer matrix, and they diminish the crosslink density.…”

Section: Thermal Characterizationmentioning

confidence: 99%

Mechanical and thermal characterization of laminar carbon/epoxy composites modified with magnesium oxide microparticles

Uzay

2021

Polymer Composites

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This paper investigates the effects of magnesium oxide (MgO) microparticles on the mechanical and thermal properties of laminated carbon fiber reinforced polymer composites. The polymer epoxy matrix was modified with 0% (pure), 2 wt%, and 4 wt% MgO fillers. Then the laminar composites were manufactured with the vacuum bag method. The energy absorption capacity and impact strength were determined from the Charpy impact tests, whereas the flexural characteristics were evaluated by conducting three-point bending experiments. Scanned electron microscopy was used to examine both the dispersion of microparticles and the fracture surface of experimentally tested specimens. Thermal performance of the polymer composites with and without MgO additives was analyzed comparatively by performing the thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The decomposition temperatures and glass transition temperatures of the composites were obtained. Approximately 30% increment in impact strength was achieved thanks to the MgO fillers. However, although the flexural strength decreased since the MgO particles caused stress concentration, the flexural modulus was not affected due to the decrease of elongation at break. The TGA and DSC instrumentations showed that the decomposition temperatures increased, and curing behaviors were improved depending upon the MgO content.

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“…Models have always been acknowledged as an appreciated attempt to decode the real world to the best of our knowledge. Modeling and optimization can take many forms, covering a combination of operating variables, depending on the technological need being addressed [ 19 , 20 , 21 , 22 , 23 ]. The benefits of models that are used to predict the behavior of materials under different environmental and loading conditions are many; these are related to the selection of appropriate materials, the reduction of the experimentation cost and shortening the time needed to standardize a material and release it on the market.…”

Section: Introductionmentioning

confidence: 99%

Interrelation between Fiber–Matrix Interphasial Phenomena and Flexural Stress Relaxation Behavior of a Glass Fiber–Polymer Composite

2021

Self Cite

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The response of fiber-reinforced polymer composites to an externally applied mechanical excitation is closely related to the microscopic stress transfer mechanisms taking place in the fiber–matrix interphasial region. In particular, in the case of viscoelastic responses, these mechanisms are time dependent. Defining the interphase thickness as the maximum radial distance from the fiber surface where a specific matrix property is affected by the fiber presence, it is important to study its variation with time. In the present investigation, the stress relaxation behavior of a glass fiber-reinforced polymer (GFRP) under flexural conditions was studied. Next, applying the hybrid viscoelastic interphase model (HVIM), developed by the first author, the interphase modulus and interphase thickness were both evaluated, and their variation with time during the stress relaxation test was plotted. It was found that the interphase modulus decreases with the radial distance, being always higher than the bulk matrix modulus. In addition, the interphase thickness increases with time, showing that during stress relaxation, fiber–matrix debonding takes place. Finally, the effect of fiber interaction on the interphase modulus was found. It is observed that fiber interaction depends on both the fiber–matrix degree of adhesion as well as the fiber volume fraction and the time-dependent interphase modulus.

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A comparative study between epoxy/Titania micro‐ and nanoparticulate composites thermal and mechanical behavior by means of particle–matrix interphase considerations

Cited by 11 publications

References 69 publications

Experimental and Prediction Study of Displacement-Rate Effects on Flexural Behaviour in Nano and Micro TiO2 Particles-Epoxy Resin Composites

Experimental and Prediction Study of Displacement-Rate Effects on Flexural Behaviour in Nano and Micro TiO2 Particles-Epoxy Resin Composites

Mechanical and thermal characterization of laminar carbon/epoxy composites modified with magnesium oxide microparticles

Interrelation between Fiber–Matrix Interphasial Phenomena and Flexural Stress Relaxation Behavior of a Glass Fiber–Polymer Composite

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