Polyurethane sealant based on hydroxy terminated polybutadiene (HTPB) capped with isophorone di-isocyanate (IPDI)

A two component polyurethane sealant has been prepared. Component A, known as prepolymer is Synthesized by capping hydroxy terminated polybutadiene (HTPB) with isophorone di-isocyanate(IPDI). Component B, known as hardener, comprises of a polyol (polyoxypropylene triol) as crosslinker methylene bis orthochloroaniline (MOCA) and benzylidene bis orthochloroaniline (BOCA) as chain extenders and fillers have been used. The shelf life of the prepolymer synthesized has been studied in terms of the stability of the isocyante content and corresponding viscosity changes with time. The sealant prepared has been characterized in terms of tensile properties and adhesion with rubber substrates. The unequal reactivity of the isocyanate has been taken advantage of, in tuning the pot life of the sealant. The effect of various urethane catalysts vis-a-vis pot life and mechanical properties of the sealant was evaluated.