Mechanical and thermal properties of epoxy composite thermal insulators filled with silica aerogel and hollow glass microspheres

Vahtrus, Mikk; Oras, Sven; Antsov, Mikk; Reedo, Valter; Mäeorg, Uno; Lõhmus, Ants; Saal, Kristjan; Lõhmus, Rünno

doi:10.3176/proc.2017.4.03

Cited by 33 publications

(21 citation statements)

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“…[61] SA, silica aerogel the effect of SA on TC could be seen in other material systems. [46,47,65] As can be seen, a similar trend with the present study is observed in epoxy/SA system. [47] It is worth mentioning that the results are statistically significant at a 95% confidence level.…”

Section: Tc Measurementssupporting

confidence: 91%

Polycarbonate/poly(methyl methacrylate)/silica aerogel blend composites for advanced transparent thermal insulations: Mechanical, thermal, and optical studies

et al. 2021

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Using transparent thermal insulators, which are low heat conductors and good light transmitters, is a brilliant idea to preserve heat energy. In this regard, silica aerogels (SAs) have attracted immense attention these days because of their unique nanoporous networks, consisting of connective silica nanoparticles and high-volume nanopores. The present study investigates the influence of incorporating 3 and 5 phr SAs on the mechanical properties, thermal conductivity (TC), and optical characteristics of polycarbonate/poly(methyl methacrylate) (PC/PMMA) (75/25, 50/50, and 25/75 w/w) blends. The scanning electron microscopy studies indicated that the PC/PMMA/SA (25/75/3) composite has the best dispersion. The highest improvements in tensile strength and Young's modulus were observed for the PC/PMMA/SA (75/25/5) composite. In addition, incorporating the SA resulted in a reduction in the impact strength of all the blends. The lowest TC was observed for the PC/PMMA/SA (75/25/5) blend composite. The TC results were compared with the data predicted by the Agari, Russell, Maxwell-Eucken, and Bruggeman models. It was found that the Agari logarithmic model has the best agreement with the experimental data. Except for PC, PMMA, PC/PMMA (25/75), and PC/PMMA/SA (25/75/3), no other samples showed optical transmittance. On average, PC/PMMA/SA (25/75/3) had 13% more light absorption than PC/PMMA (25/75). K E Y W O R D S blend composite, optical transmittancy, poly(methyl methacrylate), polycarbonate, silica aerogel, thermal conductivity | INTRODUCTIONAs an important group of engineering materials, polymer blends can be used in an extensive range of applications by tuning their chemical and physical properties. Thus, a new material possessing desired properties and enhanced performance can be prepared using polymer blending techniques. It has been well proved that creating a new resin is much more expensive than preparing a new blend. [1][2][3][4][5][6][7][8] That is why polymer blends have been the topic of immense interest in recent years.Due to its sufficient stiffness, high impact strength, good dimensional stability, high temperature stability, and, most significantly, excellent transparency, polycarbonate (PC) is utilized for various applications. However, PC suffers from some disadvantages including poor

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Section: Tc Measurementssupporting

confidence: 91%

Polycarbonate/poly(methyl methacrylate)/silica aerogel blend composites for advanced transparent thermal insulations: Mechanical, thermal, and optical studies

et al. 2021

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“…Nevertheless, the authors of both research 18,19 comment on the possible infiltration of the resin into the pores of the aerogel. This effect was further noted in the work by Vahtrus et al., 20 wherein the authors observed an increase in the thermal conductivity of aerogel/epoxy composites due to the filling of the resin into the pores of the aerogel. Kim et al., 21 however, demonstrated lower thermal conductivity values for samples manufactured using ethanol evaporation to preserve the pores; these samples showed better thermal performance when compared to as-received and plasma-treated aerogels across different volume fractions.…”

Section: Introductionsupporting

confidence: 53%

Morphological, optical and thermal characterisation of aerogel-epoxy composites for enhanced thermal insulation

Krishnaswamy

Bhattacharyya

Abhyankar

et al. 2018

Journal of Composite Materials

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The present work explores the possibility of introducing aerogel at different stages of the epoxy resin cure to identify the most effective method that ensures minimal destruction of the aerogel particles. The aerogel particles are added at 0.5 hours, 1 hour and 1.5 hours after the resin and the hardener are mixed together. Additionally, the effect of a wetting agent that improves the interface between the aerogel and the resin is also investigated. The different materials are characterised using optical images and ESEM-EDX to determine the most effective processing route. Additional data is also provided by determining the different material's optical transmittance and reflective characteristics. From the experimental results, it is observed that the addition of aerogel at the 1 hour mark proves to be the most efficient route to follow. In addition, the wetting agent displays a negligible effect on the samples in the study; hence its usage is advocated due to its influence on the interface strength. Therefore, the aerogel/epoxy/wetting agent sample with the aerogel added at the 1 hour mark looks promising. A 13.3% decrease in thermal conductivity when compared with the pure resin/hardener sample along with damage coefficient value of 0.183 demonstrates the material's potential for thermal insulation applications.

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“…The infiltration of the resin in the pores of the aerogel is also discussed in [9]. This effect was further noted in the work by Vahtrus et al [16] wherein the authors noted an increase in the thermal conductivity of aerogel/epoxy composites due to the filling of the resin into the pores of the aerogel. Therefore, works such as those of Gupta & Ricci [17] and Ge et al [8] looked at different processing methods/materials to incorporate the aerogel in an epoxy matrix with the former reducing the viscosity of epoxy and the latter using solid epoxy powder.…”

Section: Introductionmentioning

confidence: 74%

Aerogel/epoxy thermal coatings for carbon fibre reinforced plastic substrates

Krishnaswamy

Abhyankar

Marchante

et al. 2019

Journal of Adhesion Science and Technology

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The present work studies an aerogel/epoxy composite that was dip coated onto a carbon fibre substrate by adding the aerogel at the 1 hour and the 1.5 mark of the epoxy cure. Both coatings show decrease in thermal conductivity values (39% and 47% respectively) when compared to a pure epoxy coating. The coatings' reflectance spectra also provided further evidence for the existence of the nano-pores within the aerogel particles. The aerogel coating was modelled using material properties from literature and solved using finite element methods. The model, which validated using experimental data, was then used to predict the coating's performance in cyclic thermal loads. Additionally, coatings on a single surface-top and bottom; were also modelled and compared with the double coating system wherein it was seen that the double coating system had the lowest rate of temperature change and fluctuations at steady-state in contrast to the bottom coating which, showed the fastest drop in temperature as well as the highest fluctuations at steady state conditions. The performance of the top coating was in the middle.

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Mechanical and thermal properties of epoxy composite thermal insulators filled with silica aerogel and hollow glass microspheres

Cited by 33 publications

References 0 publications

Polycarbonate/poly(methyl methacrylate)/silica aerogel blend composites for advanced transparent thermal insulations: Mechanical, thermal, and optical studies

Polycarbonate/poly(methyl methacrylate)/silica aerogel blend composites for advanced transparent thermal insulations: Mechanical, thermal, and optical studies

Morphological, optical and thermal characterisation of aerogel-epoxy composites for enhanced thermal insulation

Aerogel/epoxy thermal coatings for carbon fibre reinforced plastic substrates

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