The linear master dependence for polymer melts in the non-Newtonian range

Summary The multivariable power function · _o = B( _o)^b ₁· q^b ₂· G^b ₃ (symbols are explained in the text) is proposed as the general linear master dependence for the behaviour of linear and branched polymer melts in the non-Newtonian range. It can be applied for generation of any flow curve for a given polymer sample provided that constants B, b₁, b₂ and b₃ are known. It has been found, using the experimental data on polycarbonate, that B is approximately equal to 3×10^–5 being the universal constant, and b₁=0.77 for linear polymers. Lower values of b₁ indicate the existence of branched macromolecules, and the relationship of b₁ vs G can be used for determination of branching degrees from the rheological data.