Strong and Flame-Resistant Thermoplastic Polymer Adhesives Based on Multiple Hydrogen Bonding Interactions

Reversible adhesives with a combined competence of strong bonding performance, broad substrate universality, multiple usages, and flame resistance are in substantial demand due to their wide applications and the persistent problems of increasing ecological concern. In this work, we developed thermoplastic polymer adhesives to harvest the abovementioned properties by molecularly designed copolymers including quadruple hydrogen bonds and phosphorus-containing moieties. Taking advantage of the intensive hydrogen bonding of the 2-ureido-4[1H]-pyrimidone dimer and the enhanced adhesive/substrate interfacial interaction, the designed adhesives enabled a solid bonding for various substrates including metals and polymers. In addition to the readily multiple usage capabilities due to the reversible association/dissociation of hydrogen bonding, the unique molecular design of the adhesives allows the synergetic N/P flame retardancy, leading to an excellent flame-resistant property as verified by thermal gravimetric analysis, microscale combustion calorimetry, limit oxygen index measurements, and horizontal combustion tests. We envision that the designed adhesives with desirable multifunctionality can be adopted in a range of fields such as automobile, aerospace, and high-rise residence applications.