50
For absolute measurements of viscosity, the corrected flow time multiplied by the constants indicated in
the viscometer certificate K results immediately in the kinematic viscosity in the unit mm
2
/s.
ν
= K (t-∆t
H
)
Relative viscosity is the quotient of the viscosities of a solution and the pure solvent. This has a high
significance in the evaluation of plastics. In polymer analytics, further parameters are derived from the
relative viscosity, such as the specific and inherent viscosity as well as the viscosity number and the
Fikentscher K value.
3.13 Evaluation example
DIN Ubbelohde viscometer type no. 532 10, calibrated for automatic measurements.
Capillaries no. I
Constant K = 0,009987
mm
2
/s
2
Flow time (averaged) t = 180,00
s
Hagenbach correction for 180.00 s ∆t
H
= 0,30 s (correction table in the manuals for viscometer)
Kinematic viscosity
ν
= K (t-∆t
H
)
= 0,009987
mm
2
/s
2
• (180,00 s - 0,30 s)
= 1,795
mm
2
/s*
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