Thermal Measurements on Polymeric Epoxy-Expandable Graphite Material

Asante, J. K. O.; Modiba, Fortunate; Mwakikunga, Bonex W.

doi:10.1155/2016/1792502

Cited by 6 publications

(7 citation statements)

References 22 publications

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“…This is due to the good heat conductivity of graphite worms: Although it allows a better dissipation of heat through the material, it enhances the decomposition of PP. 24 When used as the only FR compound in PP, ES 350 F5 and ES 700 F5 appear to provide similar fire protection. These are similar EG with a different expansion volume (twice as much for ES 700 F5), but the influence of this expansion volume is not noticeable here.…”

Section: Selection Of the Egmentioning

confidence: 98%

“…The presence of EG also accelerates the ignition that occurs earlier than that of neat PP (reduction between 18% and 52% of TTI, depending on EG). This is due to the good heat conductivity of graphite worms: although it allows a better dissipation of heat through the material, it enhances the decomposition of PP 24 .…”

Section: Selection Of the Expandable Graphitementioning

confidence: 99%

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Intumescent polypropylene: Interactions between physical and chemical expansion

et al. 2019

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To decrease the reaction to fire of a highly flammable plastic, polypropylene (PP), the concept of intumescence was applied. Two intumescent systems were designed, based on different mechanisms: physical expansion with expandable graphite (EG) and chemical expansion with modified ammonium polyphosphate (AP). Fire behavior of PP containing EG, AP or an AP/EG mixture with a total loading of 10wt% was evaluated by cone calorimetry at 35 kW.m-2. Thermocouples allowed measuring the temperature at the backside or inside samples over time and evaluating the thermal barrier of these intumescent materials. Two grades of AP (difference in composition) and several grades of EG (difference in expansion characteristics) were compared. Mixing AP and EG does not create a synergistic effect in studied conditions. Contrarily, the incorporation of small amount of EG in PP-AP modifies heat transfer in the coating, creating a strong anisotropy. Graphite worms are trapped vertically into the expanded AP, which increases the transverse heat conductivity (lower efficiency of the thermal barrier) and decreases the fire performance. This phenomenon disappears in thicker specimens. While a higher expansion volume of graphite worms improves fire performances of PP with only small amount of EG (1wt%), this effect is not noticeable with AP/EG mixtures.

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Section: Selection Of the Egmentioning

confidence: 98%

Section: Selection Of the Expandable Graphitementioning

confidence: 99%

Intumescent polypropylene: Interactions between physical and chemical expansion

et al. 2019

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“…As matrix material and hardener we have used DER-330 (Dow Chemical, [22]) epoxy resin and 921OP epoxyamine complex, respectively. Mass ratio of hardener in epoxy-hardener composition was 0.65.…”

Section: Methodsmentioning

confidence: 99%

Structure of intumescent epoxy composites with expandable graphite

2019

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Currently, thermoset-based polymer matrix composites are widely used for production of fire protective coatings. Intumescent properties of such coatings are highly dependent on composition. Expandable graphite is a prospective intumescent admixture; unfortunately, admixture of expandable graphite alone can lower the integrity of char residue down to unacceptable levels. The objective of the present work is to present the method that can be used for elimination of the mentioned drawback. The limiting values of expandable graphite in composite with two different admixtures - ammonium polyphosphate and ceramic cenospheres - were determined by means of study the structure of both intumescent epoxy composites and char residues of such composites. It was revealed that admixture of ceramic cenospheres leads to notable improvement of integrity of char residue. This improvement is mostly due to features of heat transfer in material with cenospheres which are characterized by low particle size and, at the same time, low heat conductance.

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“…They reported an increase in thermal degradation temperature due to the enhanced dispersion of expanded graphite in the epoxy matrix. Asante et al [38] studied the thermal degradation of epoxy/expandable graphite composites. The weight percentage of EG in the studied epoxy composites was 1, 3 and 5 wt.%.…”

Section: Introductionmentioning

confidence: 99%

Thermal Behavior and Flammability of Epoxy Composites Based on Multi-Walled Carbon Nanotubes and Expanded Graphite: A Comparative Study

et al. 2020

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Reduction of flammability and improvement of thermal stability of polymers during heating can be achieved by the introduction of fillers. Epoxy composites filled with different loadings of multi-walled carbon nanotubes (MWCNTs) and expanded graphite (EG) were prepared. The thermal oxidation stability of the prepared samples was investigated under heating in an oxidizing atmosphere using thermal analysis. The hardness was measured using the Shore D hardness test. The flammability of the prepared composites was evaluated by the ignition temperature and time-to-ignition. It was found that there was a rise in temperature corresponding to a 5% weight loss during heating for both epoxy/MWCNT and epoxy/EG composites compared to neat epoxy resin. The Shore D hardness of epoxy/MWCNT composites increased with content growth up to 0.1 wt.% and decreased with further concentration rise. The addition of MWCNTs and EG leads to an increase in the ignition temperature. It has been shown that MWCNTs improve the thermal behavior of epoxy resin in a low temperature region (below ~ 300 °C) whereas EG shows almost the same thermal behavior above 300 °C. The improvement of thermal properties can be achieved using MWCNTs and EG as fillers.

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Thermal Measurements on Polymeric Epoxy-Expandable Graphite Material

Cited by 6 publications

References 22 publications

Intumescent polypropylene: Interactions between physical and chemical expansion

Intumescent polypropylene: Interactions between physical and chemical expansion

Structure of intumescent epoxy composites with expandable graphite

Thermal Behavior and Flammability of Epoxy Composites Based on Multi-Walled Carbon Nanotubes and Expanded Graphite: A Comparative Study

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