Accurate description of intrinsic viscosity changes under polymer degradation: Narrow schulz distributions

For the Shulz distributions with weight—polydispersity from 1.4 to 2.0, the following equation is correct: ln [η] = ln [η]0 − a{ln P0 + DD − ln[PF − P0) × exp(−1.2 × DD)]}. Here, P0 and PF are viscosity–polydispersities of the initial molecular weight distribution (MWD) and the Flory distribution, respectively; a is the Mark–Houwink exponent; and DD = ln(Mn0/Mn). For more narrow MWDs, the complicated equation is required: ln [η] = ln[η]0 − a{ln P0 + DD − ln[PF − (PF − P0 × exp(−0.9 × DD − 0.28 × DD2)]}. The inaccuracy of these equations is less than 1.5%.