| 1. |
- Rahimi-Aghdam, T., et al.
(författare)
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Nitrogen and phosphorous doped graphene quantum dots : Excellent flame retardants and smoke suppressants for polyacrylonitrile nanocomposites
- 2020
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Ingår i: Journal of Hazardous Materials. - : Elsevier. - 0304-3894 .- 1873-3336. ; 381
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen (N-GQD) as well as nitrogen and phosphorous co-doped (NP-GQD) graphene quantum dots were demonstrated as novel, low cost, green and highly effective flame retardants and smoke suppressants for polyacrylonitrile (PAN) nanocomposites. The N-GQD and NP-GQD samples were synthesized by hydrothermal method with citric acid as the main reactant. For the first time, the flame retardant and smoke suppressant properties of the NP-GQD were studied. The GQDs were introduced into PAN by solvent blending route. Subsequently, thermal stability, flame retardancy, fire behavior, fire hazard and structure of the residual char were investigated by thermogravimetric analysis (TGA), UL-94 vertical burning test, cone calorimetry, FE-SEM, and Raman spectroscopy. Results showed that both PAN/N-GQD and PAN/NP-GQD nanocomposites had higher flame retardancy and smoke suppressant behavior in addition to lower fire hazard properties than neat PAN. Furthermore, the residual chars for the nanocomposite samples were increased in comparison to the neat PAN. The improvements were even more significant in case of the PAN/NP-GQD due to the synergistic effect of nitrogen and phosphorous. The improvements were mainly ascribed to the ability of the N-GQD and NP-GQD to provide stronger and larger protective char barrier layers, which was even more pronounced in case of the NP-GQD.
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| 2. |
- Rahimi-Aghdam, T., et al.
(författare)
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Polyacrylonitrile/N,P co-doped graphene quantum dots-layered double hydroxide nanocomposite : Flame retardant property, thermal stability and fire hazard
- 2019
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Ingår i: European Polymer Journal. - : Elsevier. - 0014-3057 .- 1873-1945. ; 120
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Tidskriftsartikel (refereegranskat)abstract
- ZnAl layered double hydroxide (ZnAl LDH) was synthesized via a facile hydrothermal method and then hybridized with the nitrogen and phosphorous co-doped graphene quantum dots at mild conditions. The structure and morphology of the prepared ZnAl LDH-NPGQD were characterized in detail by multiple techniques and then introduced into the polyacrylonitrile (PAN) matrix by solvent blending method. Subsequently, thermal stability, flame retardancy, fire behavior and fire hazard of the nanocomposite as well as structure of the residual char were investigated by thermogravimetric analysis (TGA), UL-94 vertical burning test, cone calorimetry and FE-SEM, respectively. The PAN/ZnAl LDH-NPGQD nanocomposite exhibited significantly higher flame retardancy and smoke suppressant capability in addition to lower fire hazard properties in comparison to the neat PAN. Moreover, incorporation of the ZnAl LDH-NPGQD into the PAN matrix increased the residual char from 0% for neat PAN to 14% for PAN/ZnAl LDH-NPGQD. These improvements were deduced to the ability of the ZnAl LDH-NPGQD to contribute in formation of stronger and larger protective char barrier layers.
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