Effect of chain flexibility in the network structure on the viscoelasticity of epoxy thermosets

Nakka, J.S.; Jansen, K.M.B.; Ernst, L.J.

doi:10.1007/s10965-011-9595-5

Cited by 37 publications

(39 citation statements)

References 19 publications

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“…Nowadays, new technical developments create a demand for new materials, one of the examples is using liquid crystalline epoxy resins to produce polymer networks [1][2][3][4][5][6][7][8][9][10]. On the other hand, recent research has shown that properties of epoxy polymers can be improved by addition of some inorganic materials as fillers [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Liquid crystal epoxy resins based on biphenyl group cured with aromatic amines - studied by dielectric spectroscopy

et al. 2013

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In this paper we investigate the dielectric response of cured epoxy resins based on biphenyl group. We chose two monomers, which were earlier synthesised, containing the same mesogen but with long and short symmetric tails. They were cured with standard amines (DDM, DMAP). Firstly we optimised conditions of the curing process by dielectric and optical observation in situ. Small differences in the dynamics of the curing process were observed in different mixtures. For the four selected products we made dielectric measurements in a wide range of frequency and temperature. Although, generally, dielectric response is similar in all the cured materials, differences can be seen in the details. At lower temperatures, quite strong relaxation process is seen in all products, its low activation energy points towards a β-process, which appears in many polymers. The Havriliak-Negami formula was fitted to the data and characteristic parameters of the observed relaxation processes were compared in detail. In some cases the α-process also appears. We conclude how the longer spacer and the type of curing process influence the electrical properties of the resin.

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Section: Introductionmentioning

confidence: 99%

Liquid crystal epoxy resins based on biphenyl group cured with aromatic amines - studied by dielectric spectroscopy

et al. 2013

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“…The storage modulus data generated a unique master curve using the shift factors. Initially, the storage modulus master curves were modeled using Hivrialiak Negami (HN) fit function 11, 28. Also, mathematical model such as generalized Maxwell model can also be used to describe the storage modulus master curves 29.…”

Section: Resultsmentioning

confidence: 99%

“…In our previous work,10, 11 model systems are selected based on epoxy‐amine reactants. In the first model system10 the average functionality of the epoxy (Bisphenol A diglycidyl ether; BADGE) resin is f E = 2.…”

Section: Introductionmentioning

confidence: 99%

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Tailoring the viscoelasticity of epoxy thermosets

Nakka

Jansen

Ernst

2012

J of Applied Polymer Sci

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This research work is aimed to understand the effect of epoxy resin chemistry on the viscoelasticity of the cured epoxy thermosets. In this article, two model systems are selected based on epoxy‐amine reactants. In the model Systems I, the functionality of the epoxy is varied. In model System II, the pendant (side) chain length in the amine is varied. It is found that by varying the initial properties (e.g., functionality, pendant chain length, mixing ratio (r), aromaticity, etc.) the network properties (crosslink density and flexibility) of the cured (or hardened) epoxy changed. The changes (or shift) in the viscoelastic properties (or viscoelasticity) of the cured epoxy is mainly due the changes in the network properties. Further, to study the time and temperature effects the viscoelastic master curves for the two model systems are generated using Time‐Temperature‐Superposition (TTS) principle. The shift in the viscoelastic master curves is modeled with a simple Kohlrausch‐Williams‐Watts (KWW) fit function. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

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“…A sample heating/Cooling rate of 5°C/min was used to determine the thermal expansion coefficient along with the Tg values between the temperature interval of 30°C-120°C. Coefficient of linear thermal expansion was calculated above and below the Tg along with the entire temperature interval The coefficient of thermal expansion (α) is determined using the equation [19].…”

Section: Thermo Mechanical Analysismentioning

confidence: 99%

Study of Thermal Properties of Granite Powder (Scrap) Reinforced Polyester Resin Composite

Paul¹,

Miah²,

Gafur³

et al. 2017

J Adv Chem Eng

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Journal of Advanced Chemical EngineeringPaul et al., J Adv Chem Eng 2017, 7:1 DOI: 10.4172/2090 Volume AbstractComposite materials are now widely used in engineering application and the scope of its application is widespread mainly for its contrapuntal properties. In this research work composites were prepared by crosslinking the polyester resin with Methyl Ethyl Ketone Peroxide and finally reinforced with the Granite scrap powder. Granite stone as filler was used at 20%, 30%, 40% and 50% with respect to the weight of unsaturated polyester resin with styrene monomer at 7.5% as constant basis mentioning that 0% sample (without Granite Filler) was also prepared to compare the results with it. Thermal analysis of the prepared composite such as Thermo Gravimetric Analysis (TGA), Thermo-mechanical Analysis (TMA) and Thermal Conductivity of the composites were analyzed along with the SEM analysis to find out correlation between thermal properties with composite surface topology. Thermo gravimetric analysis is done to determine the kinetics of thermal degradation and Thermo mechanical analysis is to determine expansion co-efficient along with Tg of polyester resin and granite blends composite. To avoid the thermo-oxidative degradation, thermal analysis was carried out for samples in nitrogen atmosphere at heating rates of 20°C/min. Thermal Conductivity analysis is performed to determine the ability of the composite to conduct heat at various temperatures.

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Effect of chain flexibility in the network structure on the viscoelasticity of epoxy thermosets

Cited by 37 publications

References 19 publications

Liquid crystal epoxy resins based on biphenyl group cured with aromatic amines - studied by dielectric spectroscopy

Liquid crystal epoxy resins based on biphenyl group cured with aromatic amines - studied by dielectric spectroscopy

Tailoring the viscoelasticity of epoxy thermosets

Study of Thermal Properties of Granite Powder (Scrap) Reinforced Polyester Resin Composite

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