Traditional textile flame retardant finishing can be achieved through two approaches. One method involves blending flame retardants with the textile raw materials during spinning to obtain flame-retardant textiles with notable effectiveness and good wash resistance, albeit at relatively higher costs. The other method involves post-finishing treatments such as impregnation, padding and baking, coating, or spray methods. While this approach is more cost-effective, the wash resistance is lower, and the long-term flame retardant effectiveness may be compromised by water and light exposure.
Various surface treatment technologies, such as sol-gel processes, adsorption of nanoparticles, layer-by-layer self-assembly, plasma treatment, deposition of biopolymers, and graft copolymer modification, have been applied to prepare multifunctional textiles with flame retardancy, waterproofing, UV protection, and self-cleaning properties.
- Sol-Gel Process
The sol-gel process involves modifying the chemical composition and arrangement of molecular building blocks to form a sol on the fabric surface, which acts as a barrier to isolate oxygen and prevent the escape of volatile substances, thereby enhancing the flame retardancy of the textile. This method offers advantages such as simple processing, high efficiency, mild reaction conditions, good film-forming properties, and ease of physical or chemical modification during the sol phase. It also enables environmentally friendly surface functionalization of the base material, allowing for tailored functional properties based on the chemical structure of the modified network. The sol-gel process has been effective in areas such as UV protection, immobilization of biomolecules, color fastness, wrinkle resistance, superhydrophobicity, and antistatic properties.
While the sol-gel process has seen significant research achievements in antistatic, UV-resistant, and superhydrophobic applications, its application in flame retardant textiles is still in its early stages. Due to the limited gel formation on the textile surface and the limited flame retardant capability of single sol components, the flame retardant effect is not significant. It requires the synergistic use of various flame retardants to achieve enhanced flame retardancy, such as the combined use of silicon sol with nitrogen- or boron-based flame retardants. Therefore, there is a need to develop synergistic sol-gel systems to improve flame retardant performance through the mutual advantages of different types of sols. Additionally, as the number of coating layers increases, flame retardant performance improves, but it also affects the fabric’s comfort and wash resistance.
- Adsorption of Nanoparticles
Nanomaterials, known for their environmental friendliness and non-toxicity, have found wide applications in flame retardancy. Nanoparticle adsorption involves immersing materials into a suspension containing nanoparticles, allowing the nanoparticles to adsorb onto the material surface. With their small particle size and large specific surface area, nanoparticles can modify the material surface, forming a dense and uniform nanocoating that inhibits the heat and flammable gas propagation. For instance, high-purity, ultrafine MH nanoparticles exhibit excellent flame retardant performance, providing protection and improving the flame retardancy of materials.
These advanced techniques demonstrate the potential for developing textiles with enhanced flame retardancy, among other functionalities, paving the way for safer and more versatile textile products.
