Flame retarding effect of graphite in rotationally molded polyethylene/graphite composites

Mhike, Washington; Ferreira, Ignatius; Li, Jing; Stoliarov, Stanislav I.; Focke, Walter Wilhelm

doi:10.1002/app.41472

Cited by 22 publications

(12 citation statements)

References 41 publications

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“…Upon exposure to high temperatures, the intercalated guest molecules decompose into gaseous species that make the graphene sheets to expand rapidly in a wormlike morphology [6].…”

Section: Introductionmentioning

confidence: 99%

Effect of Carbon Fillers in Ultrahigh Molecular Weight Polyethylene Matrix Prepared by Twin-Screw Extrusion

Rocha¹,

Cordeiro²,

Ferreira³

et al. 2016

MSA

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Oxidized (GO) and expanded (G-Exp) graphite were employed to prepare composites with ultrahigh molecular weight polyethylene (UHMWPE) matrix using masterbatches of polyethylene with different compositions. The materials and a blend of UHMWPE/HDPE were prepared by extrusion and their properties were evaluated. The effect of carbon fillers on the crystalline structure, thermo dynamic-mechanical (DMTA) and thermal properties (melting and crystallization temperatures) of the composites were discussed. The thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) measurements showed that the addition of masterbatch with GO and G-Exp significantly increased the crystallite size of composites, increasing the temperatures of melting, degradation, glass transition and the degree of crystallinity of polyethylene. DMTA analysis indicated the storage and loss moduli of composites in relation to neat UHMWPE, the blend and UHMWPE/composites. SEM micrographs showed a flatter, continuous and uniform surface meaning a compact lamellar structure. The present work resulted in interesting findings on the effects of GO on the crystalline structures, mechanical and thermal properties of UHMWPE, which can lead to generalizations useful for future work.

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“…Upon exposure to high temperatures, the intercalated guest molecules decompose into gaseous species that make the graphene sheets to expand rapidly in a wormlike morphology [6].…”

Section: Introductionmentioning

confidence: 99%

Effect of Carbon Fillers in Ultrahigh Molecular Weight Polyethylene Matrix Prepared by Twin-Screw Extrusion

Rocha¹,

Cordeiro²,

Ferreira³

et al. 2016

MSA

View full text Add to dashboard Cite

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“…However, before ignition, after cessation of the flame or in the case where this flame is turbulent, the solid is exposed to environmental oxygen. A chemical reaction between the solid and oxygen may significantly alter the dynamics of the pyrolysis process and affect key flammability characteristics such as the maximum burning rate [34] or the time to ignition [35]. Development of a robust procedure for quantification of this behavior is an important step toward comprehensive modeling of material flammability.…”

Section: Discussionmentioning

confidence: 99%

Parameterization and Validation of Pyrolysis Models for Polymeric Materials

Stoliarov

2015

Fire Technol

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A methodology for parameterization of pyrolysis models for polymeric solids is proposed. This methodology is based on a series of experiments including thermogravimetric analysis, differential scanning calorimetry, infrared radiation absorption measurement and controlled atmosphere, radiation-driven gasification experiments involving simultaneous sample mass and temperature monitoring. These experiments are interpreted using a transient pyrolysis model run in an infinitely fast (0D) and one-dimensional (1D) transport modes to derive a complete property set. This property set is subsequently validated by comparing the mass loss rate histories obtained from the gasification experiments to the model predictions. For a range of previously studied materials, these predictions were found to be, on average, within 10 to 20% of the experimental values. This manuscript provides an overview of this methodology, accompanied by examples of its application, identifies its imitations and suggests paths for future development.

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“…A previous study considered antistatic polyethylenegraphite composites using micron-sized natural flake graphite 23 . The inclusion of the natural graphite in polyethylene also improved the ignition resistance in cone calorimeter fire tests 24 . However, the impact and tensile strengths of these composites were severely compromised at the graphite loadings required to achieve static dissipation ( 10 wt.%).…”

Section: Introductionmentioning

confidence: 97%

Rotomolded antistatic and flame-retarded graphite nanocomposites

Mhike

Focke

Asante

2017

Journal of Thermoplastic Composite Materials

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Graphite nanoplatelets with an average particle size of 13 μm and an estimated flake thickness of about 76 nm were prepared by microwave exfoliation, followed by ultrasonication-assisted liquid phase delamination, of an expandable graphite. This nano-additive was used to fabricate linear low density polyethylene (LLDPE) and poly(ethylene-co-vinyl acetate) (EVA) based nanocomposite sheets using rotational moulding. The dry blending approach yielded surface resistivities within the static dissipation range at filler loadings as low as 0.25 wt.% (0.1 vol.%). However, even at this low graphite content, impact properties were significantly reduced compared to the neat polymers. Bilayer mouldings via the double dumping method proved to be a feasible approach to achieve both acceptable mechanical properties and antistatic properties. This was achieved by rotomolding nanocomposite sheets with a 1 mm outer layer containing the filler and a 2 mm inner layer of neat LLDPE. Excellent fire resistance, in terms of cone calorimeter testing, was achieved when the outer layer also contained 10 wt.% expandable graphite.

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Flame retarding effect of graphite in rotationally molded polyethylene/graphite composites

Cited by 22 publications

References 41 publications

Effect of Carbon Fillers in Ultrahigh Molecular Weight Polyethylene Matrix Prepared by Twin-Screw Extrusion

Effect of Carbon Fillers in Ultrahigh Molecular Weight Polyethylene Matrix Prepared by Twin-Screw Extrusion

Parameterization and Validation of Pyrolysis Models for Polymeric Materials

Rotomolded antistatic and flame-retarded graphite nanocomposites

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