Polythiocarbamate polymers II.—Optimum conditions for synthesis

Abstract Polythiocarbamate polymers have been prepared from a prepolymer containing terminal isocyanate groups, obtained from reaction of a low molecular weight thiol‐terminated polymer with a diisocyanate. The prepolymer was chain extended and crosslinked with diols. and triols. Optimum conditions for prepolymer formation were established. Void formation in prepolymer is avoided by use of antioxidants but is difficult to prevent in the crosslinked material. Isocyanate appeared to be consumed in a reaction other than directly with thiol, and a water‐forming oxidation may be involved. A crosslinking reaction involving the thiocarbamate hydrogen and isocyanate appears to be favoured, contrary to results with carbamates. The nature of an isocyanate and catalyst complex is discussed.