Viscosity average molecular weight of an unknown polymer using viscometry method скачать в хорошем качестве

Viscosity average molecular weight of an unknown polymer using viscometry method

Intrinsic Viscosity [η] [η] = lim(c→0) (ηₛₚ/c) = lim(c→0) (ln ηᵣₑₗ/c) This is obtained by extrapolating both reduced and inherent viscosity to zero concentration. Mark-Houwink Equation The relationship between intrinsic viscosity and molecular weight is given by the Mark-Houwink-Sakurada equation: [η] = K × M̄ᵥᵃ Taking logarithm: log[η] = log K + a × log M̄ᵥ Why do we measure flow time instead of viscosity directly? : According to Poiseuille's law, viscosity is directly proportional to flow time for the same apparatus and liquid volume. Measuring flow time is simpler, more accurate, and eliminates the need to know the capillary dimensions.