polyurethane: any of various polymers containing the urethane radical; a wide variety of synthetic forms are made and used as adhesives or plastics or paints or rubber
relation: an abstraction belonging to or characteristic of two entities or parts together
beta blocker: any of various drugs used in treating hypertension or arrhythmia; decreases force and rate of heart contractions by blocking beta-adrenergic receptors of the autonomic nervous system