Synthesis and characterization of castor oil urethane triamine networks

Castor oil was polymerized with diisocyanate and crosslinked with primary triamine (Jeffamine T-403) to form networks. The effect of triamine as a crosslinking agent on rubbery castor oil urethane elastomer was determined by measuring network parameters such as average molecular weight between crosslinks (MC) number of polymer chains per unit volume (N), tensile strength, and modulus of the networks. The crosslinking density was varied by varying the ratio of NCO : NH₂ from 0.60 to 0.95. The results indicated the formation of highly crosslinked elastomers at all NCO : NH₂ ratios employed. The tensile stregth and modulus increased with increasing crosslink density up to a value of NCO : NH₂ 0.85 and after this there was no significant change, indicating the maximum limit of improvement attainble in terms of network characteristics.