Processing degradation of polyamide 6/montmorillonite clay nanocomposites and clay organic modifier

Davis, Rick D.; Gilman, Jeffery W.; VanderHart, David L.

doi:10.1016/s0141-3910(02)00263-x

Cited by 193 publications

(114 citation statements)

References 16 publications

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“…This double peak was attributed, using the NIST (National Institute of Standards and Technology) database of infrared spectra [22], to C≡N and/or C−C≡N bonds. The formation of such compounds when PA6 degrades is already reported in the literature [28]. It could thus be assumed that GAS modifies the degradation pathway of PA6, leading to the formation of molecules presenting nitrile end-groups.…”

Section: Tga-ftirmentioning

confidence: 62%

Flame Retardancy of PA6 Using a Guanidine Sulfamate/Melamine Polyphosphate Mixture

et al. 2015

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Polyamide 6 (PA6) is a widely-used polymer that could find applications in various sectors, including home textiles, transportation or construction. However, due to its organic nature, PA6 is flammable, and flame-retardant formulations have to be developed to comply with fire safety standards. Recently, it was proposed to use ammonium sulfamate as an effective flame retardant for PA6, even at low loading content. However, processing issues could occur with this additive considering large-scale production. This paper thus studies the use of another sulfamate salt-guanidine sulfamate (GAS)-and evidences its high efficiency when combined with melamine polyphosphate (MPP) as a flame retardant for PA6. A decrease of the peak of the heat release rate by 30% compared to pure PA6 was obtained using only 5 wt% of a GAS/MPP mixture in a microscale calorimeter. Moreover, PA6 containing the mixture GAS/MPP exhibits a Limiting Oxygen Index (LOI) of 37 vol% and is rated V0 for the UL 94 test (Vertical Burning Test; ASTM D 3801). The mechanisms of degradation were investigated analyzing the gas phase and solid phase when the material degrades. It was proposed that MPP and GAS modify the degradation pathway of PA6, leading to the formation of nitrile end-group-containing molecules. Moreover, the formation of a polyaromatic structure by the reaction of MPP and PA6 was also shown. OPEN ACCESSPolymers 2015, 7 317

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Section: Tga-ftirmentioning

confidence: 62%

Flame Retardancy of PA6 Using a Guanidine Sulfamate/Melamine Polyphosphate Mixture

et al. 2015

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“…during heating: i) thermal degradation of the organic modifier of the layered silicate at temperatures of about 200-250 8C, which may affect the dispersion of the clay; [4][5][6] ii) rearrangement of the layers during the high temperature processes; [7] iii) polymer degradation or oxidation, which may be influenced by the presence of catalytic active sites at the surface of the clay and in contact with the organic matrix.…”

Section: Introductionmentioning

confidence: 99%

Heat Induced Structure Modifications in Polymer‐Layered Silicate Nanocomposites

Pastore

Frache

Boccaleri

et al. 2004

Macro Materials & Eng

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Summary: The success of the use of layered silicates in polymer nanocomposites, to improve physical and chemical properties is strictly related to a deeper knowledge of the mechanistic aspects on which the final features are grounded. This work shows the temperature induced structural rearrangements of nanocomposites based on poly[ethylene‐co‐(vinyl acetate)] (EVA) intercalated‐organomodified clay (at 3–30 wt.‐% silicate addition) which occur in the range between 75 and 350 °C. In situ high temperature X‐ray diffraction (HT‐XRD) studies have been performed under both nitrogen and air to monitor the modifications of the nanocomposite structure at increasing temperatures under inert/oxidative atmosphere. Heating between 75 and 225 °C, under nitrogen or air, causes the layered silicate to migrate towards the nanocomposite surface and to increase its interlayer distance. The degradation of both the clay organomodifier and the VA units of the EVA polymer seems to play a key role in driving the evolution of the silicate phase in the low temperature range. The structural modifications of the nanocomposites in the high temperature range (250–350 °C), depended on the atmosphere, either inert or oxidizing, in which the samples were heated. Heating under nitrogen led to deintercalation and thus a decrease of the silicate interlayer space, whereas exfoliation was the main process under air leading to an increase of the silicate interlayer space.Heat induced structural modification of EVA‐clay nanocomposite under nitrogen and air.magnified imageHeat induced structural modification of EVA‐clay nanocomposite under nitrogen and air.

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“…A more recent application, which is directly aligned with the research presented in this manuscript, was LBL clay coatings (sodium exchanged montmorillonite) of cotton fabric to improve the fire performance characteristics of this textile [26]. Clay has been extensively studied in LBL thin films [31,35,36] and, when used as an additive filler, has been shown to simultaneously improve the mechanical and fire performance attributes of polymers [37,38,39].…”

Section: Introductionmentioning

confidence: 88%

Fabrication, characterization and flammability testing of carbon nanofiber layer-by-layer coated polyurethane foam

Davis¹,

Kim²

2010

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This is the first reported use of Layer-by-Layer (LBL) assembly to fabricate thin film coatings on polyurethane foam, of incorporating carbon nanofibers (CNF) into LBL fabricated coatings, and of using LBL fabricated coatings to reduce the flammability of polyurethane foam. The (359 ± 36) nm thick four bilayer coating of polyethyleneimine/CNF (cationic layer) and poly(acrylic acid) (anionic layer) contained (50.9 ± 0.1) mass fraction % CNF. This CNF coating covered the entire internal and external surfaces of the porous foam. The distribution of the CNFs was nonuniform on the microscale with regions of large CNF aggregation to regions with individual CNFs and isolated regions that appeared to contain no CNFs. Even though the microscopic CNF distribution was non-uniform, the macroscopic CNF network armor that was generated from this LBL process significantly reduced the flammability of the foam; i.e., 55% ± 6% reduction in total heat release and peak heat release rate. This reduction caused by the CNF coating is 50% better than previously reported by incorporating twice as much CNFs directly into the foam and 12% to 47% greater than other technologies currently used to reduce foam flammability.

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Processing degradation of polyamide 6/montmorillonite clay nanocomposites and clay organic modifier

Cited by 193 publications

References 16 publications

Flame Retardancy of PA6 Using a Guanidine Sulfamate/Melamine Polyphosphate Mixture

Flame Retardancy of PA6 Using a Guanidine Sulfamate/Melamine Polyphosphate Mixture

Heat Induced Structure Modifications in Polymer‐Layered Silicate Nanocomposites

Fabrication, characterization and flammability testing of carbon nanofiber layer-by-layer coated polyurethane foam

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