Functionality Determination of Hydroxyl-Terminated Brepolymers

Present methods to determine functionality of prepolymers are based upon a network theory proposed by Stockmayer. However, the Stockmayer functionality is weighted and becomes ambiguous for prepolymer mixtures with species of varying functionality. The number average functionality allows better prediction of the cure behavior of prepolymers. This paper presents a simple theory to obtain the number average functionality from gelation test data. This theory is shown to hold for pure compounds as well as for a mixture of prepolymers. The validity of the calculated functionality data is shown with well-characterized compounds.