I have urea in powder form. What is the easiest method to synthesize polyurea using the urea powder?

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Burkhard Koehler

This is true. An alternative is the reaction of diisocyanates with water. Water can be used in excess. No exact stoichiometry is required. It can be made in a solvent which is able to solve water, e.g. dioxane. The mixture must be refluxed and the polyurea precipitates.

Mu-Shih Lin

Another option might react urea with phosgene in dichloroethane by interfacial polymerization, using tertiary amines (sch as tertiary trimethyl amine bromide, or pyridine as acid absorption). please refer to the process of interfacial polymerization of polycarbonate.