Unusually high values of the quotient d ln η/d ln M of some low-molecular-weight liquid polymers

Unusually high values of the quotient d ln η/d ln M ≡ a (where η is viscosity and M is molecular weight) found for some low-molecular-weight liquid polymers (4 ⪬ a ⪬ 8) are discussed in terms of the theory of flow processes of polymeric liquids. The effect is assigned mainly to the dependence on the chain length of the friction factor per main chain atom or atomic group but deviations of short chains from the conformation of random coils can also contribute significantly. The variation of the quotient a with temperature, however, is due to the former factor only.