Anomalous nano-barrier effects of ultrathin molybdenum disulfide nanosheets for improving the flame retardance of polymer nanocomposites

Abstract

Polymer/graphene-analogous nanosheet composites have great potential for improving their physical and mechanical properties during the past few years. Herein, ultrathin molybdenum disulfide (MoS 2 ) nanosheets were simultaneously exfoliated and non-covalently modified by ultrasonication in an aqueous solution of chitosan. The chitosan-modified MoS 2 (CS-MoS 2 ) nanosheets were then transferred from the aqueous solution to tetrahydrofuran by a simple solvent-exchange method for the fabrication of epoxy (EP) nanocomposites. Transmission electron microscopy and scanning electron microscopy were performed to display the homogeneous dispersion of CS-MoS 2 in an EP matrix. On incorporating 2 wt% CS-MoS 2 into an EP matrix, EP nanocomposites exhibited reductions of up to 43.3% and 14.6% in peak heatrelease rate and total heat release derived from cone calorimeters compared to those of neat EP, respectively. Moreover, toxic volatiles, such as hydrocarbons, aromatic compounds and CO, that escaped from the flaming EP nanocomposites were decreased compared to that of neat EP, demonstrating the higher smoke safety. Combined with the analyses of char residues and thermal stability of EP nanocomposites, the reduced fire hazards of EP nanocomposites could be attributed to the nano-barrier effects of MoS 2 , which could effectively inhibit the release of combustible gas to support burning and restrain the effusion of volatile toxic substances that cause the majority of deaths in fires.

Simultaneously electrochemical exfoliation and functionalization of graphene nanosheets: Multifunctional reinforcements in thermal, flame‐retardant, and mechanical properties of polyacrylonitrile composite fibers

“…As observed in Figure B2, the incorporation of FGNS led to a more roughly fractured appearance in PAN/FGNS‐3.0 fiber. This phenomenon indicated that the FGNS formed a strong interfacial interaction with PAN matrix . Furthermore, no existence of FGNS aggregation declared the good dispersion and embedding of FGNS in PAN matrix.…”

Multifunctions of Polymer Nanocomposites: Environmental Remediation, Electromagnetic Interference Shielding, And Sensing Applications

“…Various technologies such as solution-based processing, [33] melt mixing, [34] electrochemical polymerization, [35] have been reported to fabricate PNCs. To summarize, these approaches are generally classified into two groups, i. e. direct compounding and in situ polymerization based on whether the polymers or the monomers are mixed with the nanofillers during the preparation process.…”

Nanoreinforcements of Two-Dimensional Nanomaterials for Flame Retardant Polymeric Composites: An Overview

“…Organic phosphorus ame retardants [9,10] have high ame retardant e ciency, but most of these are liquids with poor heat resistance. In recent years, in addition to graphene, two-dimensional nanomaterials, such as hexagonal boron nitride (h-BN) [11][12][13][14][15][16], molybdenum disul de (MoS 2 ) [17][18][19][20] and black phosphorus [21] (Figure 1), have also been developed, which has greatly expanded the properties and applications of two-dimensional materials in this realm. Notably, two-dimensional materials and their derivatives have been extensively studied as photocatalysts [22,23], sensors [24], drug delivery vehicles [25], transistors [26], lithium ion batteries [27], water treatment agents [28], ion exchange [29], fuel cells [30], nano ltration membranes [31], conductive inks [32], quantum dots [33], adsorbents [34] and supercapacitors [35].…”