Predicting chain conformation and entanglement of polymers from chemical structure

The characteristic ratio C ∞ and the entanglement molecular weight M e are two key molecular parameters that control melt viscoelasticity, solid mechanical (brittle/ductile) behavior, and adhesion of polymers. We show that the characteristic ratio C ∞ and the entanglement molecular weight M e can be predicted from chemical structure by group additivity with uncertainties usually less than ∼ 7% for C ∞ and ∼ 15% for M e , comparable with the accuracies of experimental values.