Viscosity Number of Polyamide
The "viscosity number" of polyamide refers to a measure of the average molecular weight of the polymer. It is commonly used to characterize the polymer's viscosity in solution and is particularly relevant in the production and processing of polyamides.
PA, PA6 and PA66 can be dissolved in Formic Acid, m-Cresol or sulphuric acid for testing. RPV models and accessories listed below accommodate Polyamide testing.
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Viscosity Number of Polyamide
The viscosity number (also known as relative viscosity or inherent viscosity) is typically determined by dissolving a known mass of the polymer in a suitable solvent at a specific temperature and measuring the viscosity of the resulting solution.
The viscosity measurement is then compared to the viscosity of the pure solvent under the same conditions.
The viscosity number is influenced by factors such as polymer chain length and branching. Generally, higher viscosity numbers correspond to higher molecular weights and longer polymer chains.
In the case of polyamides, such as nylon, the viscosity number is an important parameter that affects the material's properties and processing characteristics, including its mechanical strength, thermal stability, and melt viscosity.
The specific viscosity number values can vary depending on the type of polyamide (e.g., nylon 6, nylon 6,6) and the measurement conditions.
Typically, viscosity numbers for polyamides fall within a certain range, with higher values indicating higher molecular weights and potentially better mechanical properties.
What solvents do I need?
Typically the polyamide is dissolved in Formic Acid or M-Cresol prior to measurement. Sulphuric acid is also in use. Cleaning and drying is typically done with the dissolving solvent and acetone.
What is the temperature of measurement?
Polyamide is typically measured at 25 degrees C. This is as specified in the method protocols of ISO 307 and ASTM D789.
What are the installation requirements
A fume hood in an air-conditioned laboratory.
How long does it take to measure the Viscosity Number of Nylon?
A complete sample cycle on the RPV Polymer Viscometer will take approximately 30 minutes. After the 30 minutes, the unit will be ready for the operator to load the next sample.
Is RV the same as Viscosity Number?
RV is short for relative viscosity. This is a measure of the increase in viscosity of a given solvent caused by the presence of a portion of fully solubilized polymer. The Viscosity Number is calculated based on the RV data.
Which test protocol is best?
ISO 307 appears to be the most widely used test protocol for polyamide. Another important test method is ASTM D789. Some resin manufacturers run proprietory test protocols in their plant laboratories.