Delayed Flammability for Natural Fabrics by Deposition of Silica Core-Amine Shell Microspheres through Dip-Coating Process

Abstract

In this study, we synthesized a SiO2-APTES core-shell microsphere (Si-NH2-MS) flame retarding material (FRM) as a heat shielding layer on natural fabrics, such as jute, cotton, and flax(cellulose) fibers. This integration was made to improve the flame retardancy property of pure jute, pure cotton, and pure flax fibers by dip-coating deposition of charged anionic and cationic polyelectrolytes to create thin multilayer coatings on the surface of the fabrics via electrostatic interactions. Additionally, through interionic interactions, a strong gluing mechanism occurs between the fabric surface and Si-NH2-MS. Pure jute, pure cotton, and pure flax burned completely within 14, 12, and 10 s, respectively, whereas 2 wt% Si-NH2-MS treated jute, cotton, and flax fibers showed delayed burning times of 21, 18, and 15 s, respectively. Furthermore, 5 wt% Si-NH2-MS treated jute, cotton, and flax fibers showed delayed burning times of 48, 41, and 23 s, respectively, due to the thermal insulation layers developed by the proposed Si-NH2-MS, which were coated uniformly on the surface of the fibers with the help of covalent bonds. Moreover, ignition resistance and self-extinguishing competencies have been observed on fabrics coated with 5 wt% of Si-NH2-MS, which could be a great advantage for indoor fire quenching applications.