Synthesis and characterization of new intrinsic self-healing hydroxyl-terminated polybutadiene (HTPB) functionalized with 2-ureido-4-pyrimidinone

The unique properties of hydroxyl-terminated polybutadiene (HTPB) make it suitable for use in various fields. Because it is impossible to use external factors to repair the damage caused by HTPB polymer in all places, it is very useful to create intrinsic self-healing properties. In this study, HTPB polymer became intrinsically self-healing during three stages of hydrobromination, amination, and the addition of 2-ureido-4-pyrimidinone groups. ATR and NMR analysis confirmed the formation of intermediates and the final self-healing compound. Also, DSC analysis showed that the glass transition temperature of the resin, which is its most important feature, has not changed. After self-healing HTPB was synthesized, this resin was mixed with isophorone diisocyanate and coated on a glass slide. The cured polyurethane coating was scratched, and an optical microscope monitored the healing process for 24 h. The corrosion test of metal plates confirmed the creation of self-healing properties in the resin. The places of scratches created on the control sample were rusted in the sodium chloride solution, while the plates with modified resin coating did not show this issue. Graphical Abstract HTPB polymer becomes intrinsically self-healing during three stages of hydrobromination, amination, and the addition of 2-ureido-4-pyrimidinone groups. These groups have a great tendency to form hydrogen bonds and give intrinsic self-healing properties to the resin. Self-healing HTPB can repair damage without the need for an external agent.