Sodium alginate-assisted exfoliation of MoS₂ and its reinforcement in polymer nanocomposites

In this work, molybdenum disulfide (MoS₂) nanosheets were facilely prepared by direct exfoliation of MoS₂ in aqueous media with the assistance of sodium alginate (SA). Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectra results showed that the raw MoS₂ was successfully exfoliated into few-layer MoS₂ nanosheets (SA-MoS₂). FTIR and thermal gravimetric analysis (TGA) investigations showed that the obtained MoS₂ nanosheets were modified by SA after exfoliation and improved dispersion in water were achieved. The obtained SA-MoS₂ nanosheets were employed to reinforce the water-soluble polymer SA. No obvious macroscopic phase separation could be found from the SA/SA-MoS₂ films. Dynamic mechanical analysis (DMA) results showed that almost 9 times enhancement for the storage modulus of SA was achieved with the incorporation of only 0.5wt% of SA-MoS₂, and the thermal stability of SA was also found improved with the addition of SA-MoS₂ according to the thermal gravimetric analysis TGA results.