Gel-spun fibers from magnesium hydroxide nanoparticles and UHMWPE nanocomposite: The physical and flammability properties

In this study, magnesium hydroxide [Mg(OH)2] nanoparticles were successfully incorporated into ultrahigh molecular weight polyethylene (UHMWPE) to produce nanocomposite fibers with reduced flammability. To improve the dispersibility in processing solvent (decalin) and the compatibility with UHMWPE, the Mg(OH)2 nanoparticles were firstly modified with oleic acid. Fourier transform infrared spectroscopy indicated that the oleic acid was covalently bonded on the surface of Mg(OH)2 nanoparticles and formed a coating layer. The modified Mg(OH)2 could disperse evenly and stably in decalin. The UHMWPE/decalin solutions with different percentages of Mg(OH)2 were gel-spun and then hot drawn to yield UHMWPE nanocomposite fibers. The addition of Mg(OH)2 nanoparticles altered the mechanical properties of the fibers by affecting their maximum draw ratio. High loading of the nanoparticles would decrease both strength and modulus of the fibers. The thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) under air flow demonstrated their flammability could be remarkably reduced. The starting thermal decomposition temperature was increased by 30 °C. Their combustion peak temperatures were also increased significantly.