Dual functions of bioinspired, water-based, reusable composite as a highly efficient flame retardant and strong adhesive

Currently, halogen-containing flame retardants and volatile organic solvent-based adhesives cause enormous damage to the environment and human health. To overcome these threats, a novel approach has been proposed to prepare formaldehyde and halogen-free green adhesive, which will also be flame retardant. Using a facile cooking method, we synthesized phosphorus functional groups decorated tapioca starch and arjuna bark composite (P@TS/AJ). As prepared P@TS/AJ composite is a water-based, reusable and eco-friendly adhesive with strong adhesive strength. The P@TS/AJ green adhesive exhibited high tensile strength, i.e., 55.5 MPa, compared with commercially available adhesive 49.4 MPa for cotton fabric. It applies to various substrates, such as textiles, paper, glass, cardboard, plastic, wood, etc. Furthermore, this bio-based strong adhesive has shown high flame retardant properties. The flame retardant property was optimized with a simple spirit lamp flame test, a limiting oxygen index (LOI) test, and a vertical flammability test (VFT). P@TS/AJ coated cotton fabric showed excellent LOI result, 46.98 % and VFT produced only 2 cm char length. Moreover, P@TS/AJ coated fabric didn't burn during the flame test and sustained more than 613 s on continuous illumination to flamed. This work not only offers a simple approach for making innovative fire-retardant adhesive coatings for many flammable surfaces but also releases a new technique for utilizing waste resources and a new strategy for the design and synthesis of advanced structural and functional materials.