What is the term for a family of polymers ranging from rubbery to brittle formed by the reaction of a diisocyanate with a polyol, also described as polyurethane?

• A. Urethane
• B. Acrylate
• C. Epoxy resin
• D. Polyamide

Answer: (A)

The main idea here is that when a diisocyanate reacts with a polyol, urethane linkages form and repeat units build a polyurethane polymer. That linkage is the defining feature, so the family is described as urethane polymers, often referred to as polyurethane. The broad range from rubbery to brittle comes from how these polymers are built: the polyol provides soft, flexible segments or rigid, stiff segments, and the overall crosslinking level can be tuned. This is why you can get flexible foams and elastomers or rigid, tough plastics from the same chemistry. Other options point to different chemistries—acrylates come from acrylic monomers, epoxy resins from epoxides, and polyamides from diamines and acids—so they don’t describe this diisocyanate–polyol system.