Preliminary synthesis of polyurethane from trimer isocyanate for self-healing polyurethane materials

Polyurethane is a flexible polymer that is frequently used in coatings, elastomers, adhesives, and foam products because of its exceptional mechanical characteristics. When employed, polyurethane frequently develops microcracks as a result of mechanical impact, chemical abrasion, and UV radiation. These cracks can reduce the mechanical properties, shorten the polyurethane's lifespan, are difficult to see visually, and are also challenging to fix. Based on the self-healing characteristic of living things, self-healing polyurethane has been developed as a replacement material to address environmental sustainability issues. The major goal of this research is to thoroughly investigate polyurethane's characteristics in order to create a self-healing polyurethane material. Polyurethane was synthesized from a polyester polyol and pentamethylene diisocyanate (PDI) trimer, while the self-healing capability was introduced by incorporating furfuryl amine and bismaleimide into the polymer structure. Furan and maleimide groups are expected to form thermally reversible cross-links via the Diels-Alder reaction, prompting the polymer to self-heal. Two methods were carried out to examine the characteristics of occurring reactions in obtaining polyurethane suitable for the synthesis of self-healing polyurethane. The first method, one-pot, demonstrated that the polyol consumed all isocyanate groups, leaving no isocyanates for reaction with furfuryl amine. The second method, two steps, was successfully performed in synthesizing a polyurethane prepolymer having furan groups attached to its structure. This method will be used in the further process of synthesizing self-healing polyurethane.