Mechanical properties of thermosets

Mullins, Michael J.; Liu, D.; Sue, Hung‐Jue

doi:10.1533/9780857097637.1.28

Cited by 16 publications

(10 citation statements)

References 24 publications

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“…The polyurethanes are in the glassy state, in fact the phase angle is close to zero degree and the viscous component of the complex modulus is negligible (G*≈ G'). This result is a typical value of a polymer in glassy state [Mullins, 2012], confirming the reliability of the tests.…”

Section: Curing Temperature Effect On Mechanical Propertiessupporting

confidence: 81%

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Viscoelastic characterisation of transparent binders for application on solar roads

Vizzari¹,

Chailleux²,

Gennesseaux³

et al. 2019

Road Materials and Pavement Design

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Polyurethanes are versatile materials and, in civil engineering, they are implemented as bonding elements, injection material to stabilize soil condition, as well as insulating and coating foams. Because of their good adhesion, their transparency, and their mechanical and thermal properties, the idea of the present research is to use it as organic matrix in a glass aggregates/glue composite used as a semi-transparent pavement surface layer.This research takes part in a wider project aiming at designing a hybrid pavement system able to harvest energy from the sun.The aim of this paper is to characterize four different types of thermoset polyurethanes in terms of curing time and visco-elastic properties. For this purpose, an experimental campaign was conducted, performing tests in a dynamic shear rheometer and a dynamic mechanical analysis.Curing time kinetics, defined as the evolution of phase angle, were modelled according to the Arrhenius law. Temperature and frequency dependence on the complex modulus were finally measured. The results demonstrate the strong dependency of the polyurethanes behaviour, overall mechanical performance and especially glass transition temperature, on the curing temperature.

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Section: Curing Temperature Effect On Mechanical Propertiessupporting

confidence: 81%

“…The Black curves referring to the polyurethanes binders never reach the value of δ = 90°. The reason comes from the cross-linked three-dimensional, covalently-bonded structure of the polyurethanes [Mullins, 2012]. Indeed, these materials are non-fusible after curing.…”

Section: Curing Temperature Effect On Mechanical Propertiesmentioning

confidence: 99%

Viscoelastic characterisation of transparent binders for application on solar roads

Vizzari¹,

Chailleux²,

Gennesseaux³

et al. 2019

Road Materials and Pavement Design

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“…Comparison of Figure 10b and 10d highlights the presence of plastic deformation in PU-CO, PU-MCO1 and PU-MCO2 before rupture. Considering that plastic deformation of thermosets starts after chain scission and is not governed by the crosslinking density [40,41], a comparison of the increasing hydroxyl index and the ultimate strain is not feasible. The introduction of TKL in the polyol strongly affected the mechanical behavior and increases the ultimate tensile stress (Figure 10a) and Young's modulus (Figure 10c) of lignin-containing polyurethanes.…”

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 99%

Bio-based polyurethane prepared from Kraft lignin and modified castor oil

Tavares¹,

Boas²,

Schleder³

et al. 2016

Express Polym. Lett.

114

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Abstract. Current challenges highlight the need for polymer research using renewable natural sources as a substitute for petroleum-based polymers. The use of polyols obtained from renewable sources combined with the reuse of industrial residues such as lignin is an important agent in this process. Different compositions of polyurethane-type materials were prepared by combining technical Kraft lignin (TKL) with castor oil (CO) or modified castor oil (MCO1 and MCO2) to increase their reactivity towards diphenylmethane diisocyanate (MDI). The results indicate that lignin increases the glass transition temperature, the crosslinking density and improves the ultimate stress especially for those prepared from MCO2 and 30% lignin content from 8.2 MPa (lignin free) to 23.5 MPa. Scanning electron microscopy (SEM) micrographs of rupture surface after uniaxial tensile tests show ductile-to-brittle transition. The results show the possibility to develop polyurethane-type materials, varying technical grade Kraft lignin content, which cover a wide range of mechanical properties (from large elastic/low Young modulus to brittle/high Young modulus polyurethanes).

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“…However, unlike PFA resin, both GO and PFA microspheres are prepared through complex, lengthy syntheses using toxic chemicals and strong acids and composites resulted in fragile films compared to dense, polymer-based substrates such as PI, making it unfeasible to form thick or free-standing films. PFA resins have similar mechanical properties to other thermosetting resins and PI (Young’s modulus of 2.3 GPa and yield point of ∼70 MPa), with a Young’s modulus of ∼0.8 GPa and tensile yield strength of ∼10 MPa. , Thus, formation of LIG directly from PFA resins, which are more mechanically robust and easily processable than PFA microspheres, would be desirable.…”

Section: Introductionmentioning

confidence: 99%

Salt-Induced Doping and Templating of Laser-Induced Graphene Supercapacitors

Hawes

Verma

Uceda

et al. 2023

ACS Appl. Mater. Interfaces

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The use of inexpensive and widely available CO2 lasers to selectively irradiate polymer films and form a graphene foam, termed laser-induced graphene (LIG), has incited significant research attention. The simple and rapid nature of the approach and the high conductivity and porosity of LIG have motivated its widespread application in electrochemical energy storage devices such as batteries and supercapacitors. However, nearly all high-performance LIG-based supercapacitors reported to date are prepared from costly, petroleum-based polyimide (Kapton, PI). Herein, we demonstrate that incorporating microparticles of inexpensive, non-toxic, and widely abundant sodium salts such as NaCl and Na2SO4 into poly(furfuryl alcohol) (PFA) resins enables the formation of high-performance LIG. The embedded particles aid in carbonization and act as a template for pore formation. While increasing both the carbon yield and surface area of the electrodes, the salt also dopes the LIG formed with S or Cl. The combination of these effects results in a two- to four-order-of-magnitude increase in device areal capacitance, from 8 μF/cm2 for PFA/no salt at 5 mV/s to up to 80 mF/cm2 for some PFA/20% Na2SO4 samples at 0.05 mA/cm2, significantly higher than that of PI-based devices and most other LIG precursors.

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Mechanical properties of thermosets

Cited by 16 publications

References 24 publications

Viscoelastic characterisation of transparent binders for application on solar roads

Viscoelastic characterisation of transparent binders for application on solar roads

Bio-based polyurethane prepared from Kraft lignin and modified castor oil

Salt-Induced Doping and Templating of Laser-Induced Graphene Supercapacitors

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