polyurethane glue belongs to a class of adhesives based on polyurethane polymers. these polymers are formed through the reaction of a polyol (an alcohol containing multiple hydroxyl groups) and an isocyanate (a compound containing the isocyanate functional group, -n=c=o). this reaction, known as polyaddition, creates a polymer chain with urethane linkages (-nh-coo-). the versatility of...