Ultra-small SiO2 nanospheres self-pollinated on flower-like MoS2 for simultaneously reinforcing mechanical, thermal and flame-retardant properties of polyacrylonitrile fiber

Abstract

Aiming to imparting polyacrylonitrile (PAN) fiber with excellent mechanical, thermal and flame-retardant properties, the 3D hierarchical f-MoS2-SiO2 hybrids were synthesized by designing the ligand conjugation of defect-rich flower-like MoS2 with thiol-functionalized SiO2 nanospheres, which were introduced into polyacrylonitrile spinning solution to fabricate PAN composite fibers. With the incorporation of 2 wt% f-MoS2-SiO2, the tensile strength and breakage elongation of f-MoS2-SiO2/PAN fiber were improved by 42% and 35% compared with pristine PAN fiber, respectively. The 5% mass loss temperature (T-5%) of f-MoS2-SiO2/PAN fiber was improved by 22 °C, implying the improved thermal stability. Moreover, f-MoS2-SiO2/PAN composite fiber exhibited good flame retardancy with 32.8% and 26.7% reduction in peak heat release rate and total heat release in contrast to pure PAN, respectively. The analysis on gaseous and condensed phase demonstrated the incorporation of f-MoS2-SiO2 hybrids retarded the effusion of pyrolytic volatiles including HCN and carbonyl compounds, and facilitated carbonization on the surface of PAN fibers to protect underlying matrix. The paper will develop MoS2-based hybrids in the application of properties reinforcement of polymer composites.