Development of multifunctional, flame retardant cotton fabric using biomass-based phosphorylated sodium lignin...

To impart flame-retardant (FR) properties to cotton fabric in a sustainable way, various biomacromolecules such as DNA, casein, and sodium lignin sulfonate (SLS) have been explored in the recent past. However, the high add-on percentage requirement of these molecules on fabric surface to obtain the desirable effect makes the fabric stiffer and also the property lacks durability. To address these issues, in the present study, a sustainable biomass-based FR agent has been synthesized by phosphorylation reaction of SLS. The synthesized phosphorylated sodium lignin sulfonate (PSLS) has been incorporated into cotton fabric through a novel and facile method wherein the cyanuric chloride acts as a cross-linker between cellulose and PSLS. The PSLS compound treated substrate with an add-on percentage of 10 has shown Limiting Oxygen Index (LOI) of 30 which has been reduced by 16 % only even after 25 washings, indicating that the treated fabric retains its flame-retardant properties after multiple washing. Additionally, the finished fabric has exhibited self-extinguishing behavior with no afterglow. Besides its flame-retardant efficacy, the treated fabric has demonstrated durable antibacterial activities (nearly 100 % efficiency). The finished fabric has shown UV ray protection with an ultra-violet protection factor (UPF) of 50+ and has offered 91 % antioxidant properties, both of which can remain effective after multiple launderings. This eco-friendly, sustainable, biomass-based FR agent has bestowed a new avenue to make cotton fabric flame-retardant along with incorporation of other multifunctionalities, all without the use of any hazardous chemicals.