Evaluation of the molecular weight distribution and crosslink density of the sol and gel components by intrinsic viscosity measurements

Abstract A theory is developed utilizing the partitioning of a partially crosslinked polymer into sol and gel fractions when the initial molecular weight may be expressed as a Schulz‐Zimm or sum of Schulz‐Zimm distributions. The results show that the initial molecular weight distribution may determined from the ratio of the initial and sol fraction intrinsic viscosities. The treatment is also extended to the case where chain degradation accompanies the cure. The theory also permits the evaluation of the gel, sol, and overall crosslink index and coefficient of each component distribution of the polymer as a function of the weight soluble fraction. The components may be the same kind or different kinds of polymers or copolymers. The computed results for a two‐component system clearly show how the differences between the molecular weights or the distributions of the two components influence the difference between the crosslink indices of the two components in the vulcanized gel.