Polypropylene (PP) and Polyethylene (PE)
The reduced viscosity of polypropylene (PP) is a measure of its relative viscosity when dissolved in a suitable solvent. It is often used as a measure of the molecular weight of the polymer. The test is usually conducted at 135 degrees C.
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To determine the reduced viscosity of polypropylene (PP) or polyethylene (PE), you will typically need to go through a number of steps.
Dissolve a known amount of the polymer sample in a suitable solvent. For PP or PE, common solvents include decalin, xylene, or tetralin. The concentration of the polymer solution should be within a suitable range to ensure accurate measurements.
Use a viscometer to measure the viscosity of the polymer solution. The viscometer should be chosen based on the viscosity range of the solution and the instrument's capabilities. Measure the viscosity of the polymer solution under controlled conditions, including temperature and shear rate, to ensure accuracy and reproducibility.
Measure the viscosity of the pure solvent under the same conditions used for the polymer solution. This serves as a reference value for the viscosity of the solvent.
Use the viscosity values obtained from measuring the solvent and the solution, you can calculate the reduced viscosity.
These values can provide information about the molecular weight of the polymer, with higher reduced viscosity values typically corresponding to higher molecular weight polymers.
It's important to ensure that the measurements are performed accurately and under controlled conditions to obtain reliable results. Additionally, it's recommended to consult relevant standards or literature for specific guidelines and best practices for viscosity measurements of polymers like PP and PE.
What solvents do I need?
Decalin (decahydronaphtalene) is a commonly used solvent for this test. Other solvents include Toluene, Tetralin or Xylene.
What is the temperature of measurement?
The most commonly used test method, ISO 1628 - 3, specifies a measurement temperature of 135 degrees C. When xylene is used the temperature of measurement is 50 degrees C.
What are the installation requirements?
The instrument must be accommodated in a fume hood in a temperature controlled laboratory environment.
How long does a test take?
From the solution is charged into the viscometer tube, the time to results is approximately 10 minutes. Fully automated cleaning and drying of the sample path then takes another 10-15 minutes.
Is reduced viscosity the same as IV?
Reduced viscosity and Intrinsic Viscosity are two different units of result. For details, please see the instructions detailed in ISO 1628 - 3.