Exploring structure/property relationships to health and environmental hazards of polymeric polyisocyanate prepolymer substances-3. Aquatic exposure and hazard of aliphatic diisocyanate-based prepolymers.

The water extractability and acute aquatic toxicity of seven aliphatic diisocyanate-based prepolymer substances were investigated to determine if lesser reactivity of the aliphatic isocyanate groups, as well as increased ionization potential of the expected (aliphatic amine-terminated) polymeric hydrolysis products, would influence their aquatic behavior compared to that of previously investigated aromatic diisocyanate-based prepolymers. At loading rates of 100 and 1,000 mg/L, only the substances having log K ≤9 exhibited more than 1% extractability in water, and a maximum of 66% water extractability was determined for a prepolymer having log K = 2.2.