A Flame-Retardant Phytic-Acid-Based LbL-Coating for Cotton Using Polyvinylamine

Abstract

Phytic acid (PA), as a natural source of phosphorus, was immobilized on cotton (CO) in a layer-by-layer (LbL) approach with polyvinylamine (PVAm) as the oppositely charged electrolyte to create a partly bio-based flame-retardant finish. PVAm was employed as a synthetic nitrogen source with the highest density of amine groups of all polymers. Vertical flame tests revealed a flame-retardant behavior with no afterflame and afterglow time for a coating of 15 bilayers (BL) containing 2% phosphorus and 1.4% nitrogen. The coating achieved a molar P:N ratio of 3:5. Microscale combustion calorimetry (MCC) analyses affirmed the flame test findings by a decrease in peak heat release rate (pkHRR) by more than 60% relative to unfinished CO. Thermogravimetric analyses (TGA) and MCC measurements exhibited a shifted CO peak to lower temperatures indicating proceeding reactions to form an isolating char on the surface. Fourier transform infrared spectroscopy (FTIR) coupled online with a TGA system, allowed the identification of a decreased amount of acrolein, methanol, carbon monoxide and formaldehyde during sample pyrolysis and a higher amount of released water. Thereby the toxicity of released volatiles was reduced. Our results prove that PA enables a different reaction by catalyzing cellulosic dehydration, which results in the formation of a protective char on the surface of the burned fabric.

One‐step flame retardant/hydrophobic finishing on cotton fabric with ammonium salt of hexamethylenediamine ‐ N, N, N′, N′ ‐ tetra (methylphosphonic acid) doped silica sol

“…Besides, a significant broadband near 1672 cm −1 appears due to the NH 2 and the OH (in PO[OH]) deformation vibrations. For the residual carbon of the modified sample, the intensity of the band at 1672 cm −1 increased and was assigned to CC (in PCC or alkenes) double bond stretching vibrations, which resulted in the formation of char residues 37 . The finished cotton fabric has excellent thermal stability, which can greatly reduce the occurrence of fire and the losses caused by it.…”

Layer-by-Layer Deposition: A Promising Environmentally Benign Flame-Retardant Treatment for Cotton, Polyester, Polyamide and Blended Textiles

“…The majority of scientific papers on the application of LbL deposition to reduce the flammability of fabrics has been devoted to cotton. The compounds used for the deposition of cotton are long-chain organic polymers [85][86][87][88][89] and short-chain organic molecules [90][91][92], as well as suspensions of inorganic nanoparticles [93][94][95].…”

“…Zilke et al pre-treated cotton fabric with BPEI (1 wt%) to add a positive charge on the fabric surface and then dipped it into anionic PA (5 wt%, pH 0.7) and cationic 5 wt% polyvinyl amine (PVAm), forming 5, 10 and 15 BLs. The lowest number of BLs passing horizontal flame spreading test was 10 [89]. PVAm is a linear polymer with the highest content of primary amine functional groups of any polymers [103].…”

“…lowest number of BLs passing horizontal flame spreading test was 10 [89]. PVAm is a linear polymer with the highest content of primary amine functional groups of any polymers [103].…”

Phytic Acid-Iron/Laponite Coatings for Enhanced Flame Retardancy, Antidripping and Mechanical Properties of Flexible Polyurethane Foam

“…Meanwhile, PA has a wide range of sources and exists in various plant tissues, such as beans, cereals, and oilseeds [ 29 , 30 ]. When PA is used as a flame retardant, it can act as an acid source to form a complete intumescent flame-retardant system with other carbon sources, and can also cooperate with metals, nitrogen-containing compounds, and other flame retardants [ 31 , 32 , 33 ]. Recently, PA and sodium lignosulfonate (SLS) have been used to create bio-based coating via dip-coating on polyurethane (PU) sponge [ 34 ].…”