A new method for measuring the degree of crosslinking in elastomers

A rapid method for determining the degree of crosslinking in elastomers is described which involves measuring equilibrium compression modulus at very small deformations on solvent-swollen samples. The elastomer used was a polyether urethane vulcanized by an accelerated sulfur recipe. The degree of crosslinking as measured by the compression method agreed with that measured by the extension method within 1–3%. Both methods agreed reasonably well with the theoretical values calculated from the sulfur level, polymer molecular weight, and crosslink structure.