Applications Polymers

Solution viscosity – Quality feature of plastics


Determining solution viscosity as a measure for the medium molecular mass of a polymer is one of the most tried-and-tested methods and the most sensitive method to evaluate the molecular identity of many plastics.

Since the processing and usage properties of the plastic depend strongly on its molecular structure, the quality of the plastics can be easily monitored through the solution viscosity or most of them can be optimized and the necessary figure can be determined from this.

Binding standards for the practical execution of viscosity measurement exist for plastics.

These determine, for example, solvents, concentration, sample preparation, viscometer type and size, measuring temperature, number and reproducibility of the processing time measurements as well as the type of evaluation.

As the measurement result, the relative viscosity is always calculated from the ratio of viscosities of the polymer solution and of the solvent.

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Technical polymers

Viscosity number of polyamides (PA) and polybutylene terephthalates (PBT)

Transparent polymers

Viscosity number and IV value of polyesters (PC, PMMA, PET)


Molar mass and IV value of polypropylene and polyethylene (UHMWPE)


Determining K-value acc. to Fikentscher (chain length of the basic polymers)

Medical Polymers

Molar mass and IV value of hyaluronic acid products and absorbable polymers

Cellulose and papers

Degree of polymerization of insulation paper using solution viscosity

LAUDA Scientific Viscometry systems – Advantages and benefits at a glance



Intuitive measuring principle

LAUDA Scientific measuring systems with high degree of automation


Easy, affordable execution with stopwatch

Parallel measurement positions accelerate the process

Contact with solvents is reduced

Safe operation even by semi-skilled shift workers

Supplies important figures quickly for the chain lengths of polymers and their changes

Comparison of the specifications with current figures in the quality check

Production control in shift operation

Incoming components inspection of raw polymers

Outgoing components inspection of semi-finished products and compounds

Sample preparation and principle are determined in a few standards

High selectivity on properties of the polymer chain

Useful tool for polymer research

Worldwide comparability

Can be carried out everywhere with minimum effort

Results practically uninfluenced by filler materials or additives to the plastic, like, for example, with the melt flow index

High degree of flexibility

Applicable in many ways

Easy to implement

In some industries, e.g. automotive, the solution viscosity is required

Compensation for extra effort as competitive advantage

Continuous monitoring during product generation

Analysis of finished product over the entire life-span and recycling