Multigram-scale fabrication of organic modified MoS₂nanosheets dispersed in polystyrene with improved thermal stability, fire resistance, and smoke suppression properties

Abstract

A multigram-scale fabrication method was developed to modify molybdenum disulfide (MoS 2 ) nanosheets with cetyl trimethyl ammonium bromide (CTAB), and the CTAB-modified MoS 2 nanosheets (CTAB-MoS 2 ) were applied to improve the properties of polymers. CTAB-MoS 2 dispersed well in organic solvents and was incorporated into polystyrene (PS) by a masterbatch-based melt-blending method. The morphology, thermal behavior, fire resistance, and smoke suppression properties of the nanocomposites were studied. The CTAB-MoS 2 nanosheets dispersed well in PS and exhibited a partial exfoliation structure.The incorporation of 3 wt% CTAB-MoS 2 nanosheets led to an increase in thermal degradation temperature (43-60 C) and char formation as well as a reduction of the peak heat release rate (PHRR) (20%). Moreover, the addition of CTAB-MoS 2 nanosheets significantly decreased the smoke production rate (SPR), the peak specific extinction area (peak-SEA) values (52% reduction), and the gaseous products. The improvements in the thermal stability, fire resistance, and smoke suppression properties of PS nanocomposites were ascribed to good dispersion of modified MoS 2 nanosheets, physical barrier effects, and catalytic char function of MoS 2 nanosheets.

Enhanced Thermo‐Mechanical Stiffness, Thermal Stability, and Fire Retardant Performance of Surface‐Modified 2D MoS2Nanosheet‐Reinforced Polyurethane Composites

“…This is in agreement with a previous report, because MoS 2 and M‐MoS 2 act as catalysts to accelerate the early‐stage thermal degradation of polymer to form a thermally insulating char. Moreover, MoS 2 nanosheets in the polymer matrix increase the viscosity and rapidly increase the surface temperature during heating, while the physical barrier effect of MoS 2 nanosheets allows quick polymer decomposition . From the derivative plots, it can be seen that the maximum weight loss rate is higher in pristine PU than in the PU composites.…”

“…After the addition of MoS 2 and M‐MoS 2 to the PU, the TTI values of the composites slightly decreased, since the MoS 2 nanosheets catalyze polymer degradation as explained in the previous section. Moreover, MoS 2 nanosheets in the polymer matrix increase the viscosity and rapidly increase the surface temperature with the physical barrier effect of the nanosheets, and therefore, the polymer decomposes sooner than neat PU . In other words, it burns in the early stage to form a thermally insulating char, which can prevent heat and oxygen from contacting the polymer underneath, resulting in decreased flammability.…”

“…These M‐MoS 2 nanosheets are randomly aligned in the polymer matrix by formation of strong interfacial hydrogen bonds with PU chains, which is important to improve the mechanical and FR property of resulting PU composites. Owing to its high aspect ratio of MoS 2 nanosheets, it acts as strong physical barrier to lower the transfer of combustible pyrolysis components and accelerate the polymer degradation with increasing surface temperature . Therefore, in presence of M‐MoS 2 nanosheets accelerate the polymer degradation in early stage to forms high cross‐linked char and also it release non‐flammable gases such as NH 3 to the gas phase and dilutes the combustible gases.…”

The influence of melamine phosphate modified MoS2 on the thermal and flammability of poly(butylene succinate) composites

“…In comparison with the pristine MoS 2 , the (002) peak of MAP‐MoS 2 had shifted to 2 θ = 9.3°, which corresponded to interlayer distance of 0.95 nm, indicating the attachment of MAP molecules on the surface of the nanosheets enlarged the interlayer of modified MoS 2 and, thus would favor the intercalation of polymer chains . It had been generally accepted that the expansion of the interlayer space of the layered compounds was due to successful intercalation of the intercalating agents . FTIR analysis spectrum of MoS 2 and MAP‐MoS 2 (Fig.…”

Preparation of polystyrene/triphenyl phosphate composites by suspension polymerization and melt extrusion method — A comparative study

“…The PHRR of PS/TPP-M was reduced by 17% with respect to that of pure PS, whereas that for PS/TPP-S was reduced by 24%. The reduction in the PHRR could be correlated with the TPP particle dispersion and distribution in the polymer [37] . Via suspension polymerization, TPP can form nanoparticles and disperse uniformly in the PS matrix; however, nanodispersion of TPP in PS/TPP-M cannot be realized.…”