H3PO3-modified hyperbranched polyethyleneimine/montmorillonite coatings for flame-retardant polyester/cotton fabrics

• A flame-retardant polymeric electrolyte composite coating (HPEI/MMT) was developed. • HPEI was protonated by phosphorous acid to improve flame retardant efficiency. • LOI value of the coated fabric can reach 64.9 % with 15.3 % PPM addition. Polyelectrolyte complex coatings have been developed for flame-retardant fabrics, which demonstrate advantages in simplified operations and high flame retardancy. In this study, a polyelectrolyte complex coating (called PPM) was developed through the integration of H 3 PO 3 , hyperbranched polyethyleneimine, and montmorillonite, and was subsequently applied onto polyester/cotton fabrics using a one-step blade coating method. We thoroughly investigated the chemical structure, surface morphology, flame retardancy performance, thermal decomposition behavior, and mechanical properties of the coated fabrics. It was found that H 3 PO 3 was incorporated into the PPM coating via ionic bonds, with a phosphorus atomic content of 0.9 %. Homogeneous and continuous coatings were formed on the surface of fabrics because of good film-forming ability of PPM. When the PPM loading was 15.3 %, the coated fabric showed a limiting oxygen index value of 64.9 % and quickly self-extinguished during the vertical flammability test with a damage length of 63 mm. In the cone calorimetry test, the PPM-coated fabric presented a 50 % reduction in peak heat release rate and a 52 % decrease in total smoke production. The PPM coating exhibited flame-retardant activities in both condensed and gaseous phases.