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Abstract

Polyurea is a relatively new entrant in the field of protective coatings, particularly for improved blast resistance and ballistic performance [1,2]. These elastomers are well known for their short 'curing' times, excellent durability and exceptional adhesion to a variety of surfaces. In view of the rapid kinetics of isocyanate-amine reaction, conventional techniques like brush coating cannot be employed to form coatings [3]. Polyurea is commercially available as a two-part formulation: Side A, an isocyanate prepolymer duly diluted with a cyclic organic carbonate for viscosity matching with Side B, which is a blend of amines. For practical processing, the isocyanate and amine are reacted just prior to being sprayed through the nozzle over any surface, which need to be coated. Seamless polyurea coatings can be formed practically instantaneously, in a matter of just a few seconds. Figure 1: Bidentate hydrogen bonds between polyurea chains [6].