engleski

Environmentally-Benign Phytic Acid-Based Multilayer Coating for Flame Retardant Cotton

Chemically bleached cotton fabric was treated with phytic acid (PA), chitosan (CH) andurea by means of layer-by-layer (LbL) deposition to impart flame retardant (FR) behavior using onlybenign and renewable molecules. Samples were treated with 8, 10, 12 and 15 bilayers (BL) of anionicPA and cationic CH, with urea mixed into the aqueous CH solution. Flammability was evaluated bymeasuring limiting oxygen index (LOI) and through vertical flame testing. LOI values are comparableto those obtained with commercial flame-retardant finishes, and applying 10 or more bilayersrenders cotton self-extinguishing and able to pass the vertical flame test. Microscale combustioncalorimeter (MCC) measurements show the average reduction of peak heat release rate (pHRR) ofall treated fabrics of ~61% and the reduction of total heat release (THR) of ~74%, in comparisonto untreated cotton. Decomposition temperatures peaks (T1max) measured by thermogravimetricanalyzer (TG) decreased by approximately 62◦C, while an average residue at 650◦C is ~21% for 10 and more bilayers. Images of post-burn char indicate that PA/CH-urea treatment is intumescent.The ability to deposit such a safe and effective FR treatment, with relatively few layers, makes LbL analternative to current commercial treatments.

layer-by-layer assembly ; flame retardant ; cotton ; phytic acid ; chitosan ; urea

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