Abstract
We show how 1H–NMR transversal relaxation and 2H–NMR spectroscopy can be used for the determination of the number average molecular mass MC in typical elastomers at temperatures well above the glass transition temperature. MC‐results of the different NMR methods are compared among one another and with MC‐results of other common independent methods. Moreover, the NMR measurements provide a number of additional useful parameters: correlation times, portions of dangling chain ends and of sol molecules, molecular order.