Cannon Instrument miniPV-X - Manual (Page 29)

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CANNON ® miniPV-Series Automatic Viscometer with VISCPRO ® Instruction & Operation Manual
Version 1.a— January, 2011; CANNON ® Instrument Company
2139 High Tech Road • State College, PA 16803 • USA
the density of both will not be included in relative viscosity calculations.
Unity Reference blank
A preexistent blank, Unity Reference, is hard-coded in the VISCPRO®
software with a value of “1”. Users selecting this blank when running an
RV
sample are effectively calculating the kinematic viscosity of the solution in
a
manner which permits them to use VISCPRO® polymer report options.
Testing volatile samples
The environment for viscosity measurement using the MiniPV
AIRBATH and compound viscometer is much different than it would be
with a conventional liquid bath and a U-shaped viscometer. Because of
the continuous downward flow of air in the AIRBATH, evaporation of
sample components have the potential to adversely affect the analysis.
This
is because evaporation changes the composition of the sample and may
also affect temperature stability).
If you are testing at higher temperatures and/or with samples containing
components which may evaporate during the analysis, cover the sample
with aluminum foil or other easily penetrable membrane and secure with
the “O” ring and cap supplied for that purpose with the MiniPV. This
will seal the sample until the viscosity measurement is performed. Then
the
viscometer tip penetrates the aluminum foil/membrane and performs the
entire analysis without withdrawing completely from the sample vial.
NOTES If the aluminum foil has been penetrated and the sample has remained
in the analysis chamber for more than a few minutes, do not attempt to
reuse the sample. A new sample should be prepared.
It is especially important to cover the samples when performing solution
viscosity analysis of polymers. Even a slight change of composition
caused by solvent evaporation may cause significant error.
Even samples that are high in viscosity may still contain volatile compo-
nents;