A cationic, durable, P/N-containing starch-based flame retardant for cotton fabrics

Area of Science:

• Materials Science
• Polymer Chemistry
• Textile Engineering

Background:

• Developing durable flame retardants for textiles is crucial for safety.
• Existing treatments often lack longevity after washing.
• Cationic flame retardants offer potential for improved fabric interaction.

Purpose of the Study:

• To synthesize and characterize a novel cationic flame retardant, DTPAP.
• To evaluate the flame retardancy and durability of DTPAP-treated cotton fabrics.
• To elucidate the flame retardant mechanism of DTPAP.

Main Methods:

• Synthesis of DTPAP (6-(2-(dimethoxy phosphoryl)-2-(trimethyl ammonium)) methoxy-2-methoxy-polysaccharide ammonium phosphate).
• Structural verification using NMR and FTIR spectroscopy.
• Flame retardancy tests including Vertical Flame Test (VFT) and Limiting Oxygen Index (LOI).
• Durability assessment after 50 laundering cycles (LCs).
• Surface analysis using X-ray photoelectron spectroscopy (XPS) and Energy Dispersive X-ray Spectroscopy (EDS).
• Combustion behavior analysis using Cone Calorimetry.

Main Results:

• DTPAP was successfully synthesized and grafted onto cotton fabrics via P(=O)-O-C bonds, confirmed by FTIR and XPS.
• DTPAP-treated fabrics exhibited excellent flame retardancy, passing VFT with an initial LOI of 43.9%.
• Flame retardancy was retained after 50 LCs, with LOI remaining at 29.9% and passing VFT.
• DTPAP treatment resulted in lower metal ion content compared to other cationic flame retardants.
• Cone calorimetry indicated a condensed-phase flame retardant mechanism with no concentrated heat release.

Conclusions:

• DTPAP is a durable, cationic flame retardant for cotton fabrics.
• The P(=O)-O-C linkage ensures strong grafting and high durability.
• The reduced ion exchange due to cation introduction enhances flame retardant longevity.
• DTPAP offers a promising approach for developing high-performance, durable flame-retardant textiles.