Pulp & Cellulose
The limiting viscosity of cellulose provides a key insight into the strength of the pulp/cellulose at the mill. A high limiting viscosity corresponds to longer polymer chains and and a higher degree of polymerization.
Tappi T230, ISO 5351 and ASTM D1795 are the main method protocols for Certificate of Analysis testing of pulp samples.
RPV systems as listed below offer automation of this labour intensive and delicate test.
Pulp & Cellulose - ISO 5351, ASTM D1795, Tappi T230
The limiting viscosity of cellulose is a measure of the degree of polymerization (DP) of cellulose molecules in a solution. It is typically determined by measuring the viscosity of a solution containing a known concentration of cellulose dissolved in a suitable solvent, such as cupriethylenediamine (CED) solution.
In practical terms, the limiting viscosity of cellulose can be used to assess the quality and properties of cellulose-based materials, such as paper, textiles, and films. For example, in the production of electrical paper, which relies on cellulose as the main component for its insulating properties, controlling the degree of polymerization can ensure that the paper has the desired mechanical strength, dielectric properties, and processability.
Additionally, the limiting viscosity of cellulose can be used as a parameter in quality control processes to ensure consistency in cellulose-based products and to monitor the effects of processing conditions or chemical treatments on the molecular weight distribution of cellulose.
Overall, the limiting viscosity of cellulose serves as an important parameter for understanding and controlling the properties of cellulose-based materials in various industrial applications.
What solvents do I need?
Prior to measurement, the cellulosic material must be fully solubilized in a 50/50 mixture of water and cuprithylene diamine (CED). On completion of the measurement, the Automated pulp viscometer cleans the sample path with water and the uses acetone as a drying solvent.
What is the temperature of measurement ?
25 degrees C. Viscometers are held at temperature in a temperature controlled viscometer bath. Alternatively, one type of viscometer has a jacket design, where the tempered water is circulated through for temperature control.
What are the installation requirements?
A laboratory environment with a stable temperature. Access to venting a tube into a fume hood or to a duct, which leads to the outside. The instrument itself does not need to be fitted in a fume hood.
How long does it take to measure the limiting viscosity of pulp?
A complete measurement cycle takes approximately 30 minutes on the PSL Rheotek automated pulp viscometer. This also includes automated cleaning and dyring of the sample path of the instrument.
Is there an easier way to do this without solvents?
The internationally recognised test method protocols for pulp and cellulose viscosity all require the material to be solubilised in a mixture of water and solvent.