The ASTM D5225 test method specifies the use of a differential or modified differential viscometer to determine the solution viscosity of polymers. This test applies to all polymers that dissolve entirely without a chemical reaction or degradation, forming stable solutions over time and temperature. All types of synthetic polymers, biopolymers, proteins, and peptides can be measured using the differential viscometer utilized in the test. The ASTM D5225 test method also allows for quick viscosity characterization of polymers.
ASTM D5225 Test Method
| Measurement of Viscosity | ASTM D5225 uses a special setup with four capillaries, resembling a Wheatstone bridge. The solvent flows through these capillaries at a steady pressure, keeping the pressure sensor at zero. Then, the solution is injected, and the pressure slowly increases until it stabilizes. This final pressure value is directly related to the solution’s viscosity. |
| Monitoring of Differential Pressure | The differential pressure is continuously tracked using a strip chart recorder or computer, establishing a baseline for recording ∆P. |