Impact properties and rheological behavior of exfoliated graphite nanoplatelet-filled impact modified polypropylene nanocomposites

Duguay, Alex J.; Kızıltaş, Alper; Nader, Jacques W.; Gardner, Douglas J.; Dagher, Habib J.

doi:10.1007/s11051-014-2307-4

Cited by 13 publications

(13 citation statements)

References 14 publications

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“…Similar results were found for graphene‐based poly(vinyl alcohol) composites and were related to their intercalated structure . Consequently, the presence of rGO‐g intercalated aggregates increased the rigidity and hindered dissipation of mechanical energy . The significant increase in E values for the TPS/PLA/rGO‐g composites was an indication of the compatibilizing effect of rGO‐g, and corroborated the SEM results.…”

Section: Resultssupporting

confidence: 84%

Preparation and Properties of Poly(lactic Acid)/Thermoplastic Starch/Reduced Graphene Oxide Composites

Ferreira

Andrade

2018

Macromolecular Symposia

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Glucose‐reduced graphene oxide (rGO‐g) is incorporated in thermoplastic starch (TPS)/polylactic acid (PLA) 1:1 immiscible blend by one‐step extrusion. X‐ray diffraction shows increased crystallinity for TPS/PLA/rGO‐g composites and intercalation of rGO‐g lamellae. Differential scanning calorimetry indicated that the rGO‐g filler induced crystal nucleation in the composites. Scanning electron microscopy images obtained for the composites presented improved adhesion between the phases. Thermogravimetric analysis results showed improvement in the maximum degradation rate (Tmax) for TPS and for PLA phases in the composites. Tensile tests revealed increase of rigidity of the composites in relation to the neat blend, reaching 10‐fold increase of the Young's modulus for the composition with rGO‐g incorporated at 5.0% mass content. The presence of rGO‐g intercalated lamellae resulted in a small volume of conductive pathways, which led to conductivity values around σ = 10−8 and 10−7 S cm−1 for the composition with rGO‐g incorporated at 3.0 and 5.0% mass content, respectively.

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Section: Resultssupporting

confidence: 84%

Preparation and Properties of Poly(lactic Acid)/Thermoplastic Starch/Reduced Graphene Oxide Composites

Ferreira

Andrade

2018

Macromolecular Symposia

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“…These results from tensile and impact tests are most probably related to the presence of large rGO aggregates within the PLA phase (in the bulk or at the interface), as detected by XRD. These large aggregates would certainly increase rigidity and hinder dissipation of mechanical energy .…”

Section: Resultsmentioning

confidence: 99%

Tuning the mechanical and electrical conductivity properties of graphene‐based thermoplastic starch/poly(lactic acid) hybrids

2018

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Environmentally friendly approaches were followed to develop thermoplastic starch (TPS)/poly(lactic acid) (PLA) extruded hybrids at 70:30 and 30:70 compositions, with the incorporation of reduced graphene oxide at 1.0, 3.0, and 5.0 mass% contents. Glucose was chosen as reagent to reduce graphene oxide (GO) to the rGO sample. Theoretical models predicted that the final location of rGO was at the interface of the components. The adhesion between the polymeric phases in the hybrids, observed by scanning electron microscopy, and the improved compatibilization suggested by mechanical and dynamic mechanical analyses indicated that a large fraction of rGO platelets were at the interface. X‐ray diffraction showed that rGO acted as a nucleating agent for PLA and revealed a better dispersion of rGO lamellae within TPS. Consequently, the phase composition of the TPS/PLA/rGO hybrids played an important role on the properties of the hybrids. For the neat TPS/PLA blend at 70:30 composition, ɛmax = (4.7 ± 0.6)% and the electrical conductivity was found around 10−13 S/cm. The incorporation of rGO led to more flexible and to higher conductivity materials, with ɛmax = (15.1 ± 0.7)% and σ = 1.1 × 10−5 S/cm for the hybrid with rGO at 5.0 mass% content. POLYM. COMPOS., 40:E1131–E1142, 2019. © 2018 Society of Plastics Engineers

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“…The incorporation of GNP in polyamide (PA12) shows that GNP alters the glass transition temperature and crystallization characteristics of PA12 [97]. On the other hand, the addition of GNP to polypropylene decreases the impact strength [98]. The incorporation of GNP in polycarbonate is associated with a percolation threshold of 4.0 vol% [99]; at 5 vol% GNP (above the threshold), the electrical resistivity remains high at 4.0 9 10 7 X cm and the thermal conductivity remains low at 0.37 W/(m K) [99].…”

Section: Graphite Nanoplatelet Compositesmentioning

confidence: 99%

A review of exfoliated graphite

2015

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Exfoliated graphite (EG) refers to graphite that has a degree of separation of a substantial portion of the carbon layers in the graphite. Graphite nanoplatelet (GNP) is commonly prepared by mechanical agitation of EG. The EG exhibits clinginess, due to its cellular structure, but GNP does not. The clinginess allows the formation of EG compacts and flexible graphite sheet without a binder. The exfoliation typically involves intercalation, followed by heating. Upon heating, the intercalate vaporizes and/or decomposes into smaller molecules, thus causing expansion and cell formation. The sliding of the carbon layers relative to one another enables the cell wall to stretch. The exfoliation process is accompanied by intercalate desorption, so that only a small portion of the intercalate remains after exfoliation. The most widely used intercalate is sulfuric acid. The higher concentration of residue in unwashed EG causes the relative dielectric constant (50 Hz) of the EG to be 360 (higher than 120 for KOH-activated GNP), compared to the value of 38 for the water-washed case. An EG compact is obtained by the compression of EG at a pressure lower than that used for the fabrication of flexible graphite. Compared to flexible graphite, EG compacts are mechanically weak, but they exhibit viscous character, outof-plane electrical/thermal conductivity and liquid permeability. The viscous character (flexural loss tangent up to 35 for the solid part of the compact) stems from the sliding of the carbon layers relative to one another, with the ease of the sliding enhanced by the exfoliation process.

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Impact properties and rheological behavior of exfoliated graphite nanoplatelet-filled impact modified polypropylene nanocomposites

Cited by 13 publications

References 14 publications

Preparation and Properties of Poly(lactic Acid)/Thermoplastic Starch/Reduced Graphene Oxide Composites

Preparation and Properties of Poly(lactic Acid)/Thermoplastic Starch/Reduced Graphene Oxide Composites

Tuning the mechanical and electrical conductivity properties of graphene‐based thermoplastic starch/poly(lactic acid) hybrids

A review of exfoliated graphite

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