ASTM D6188 Test for Viscosity of Cellulose by Cuprammonium Ball Fall

ASTM D6188 is used to estimate the molecular weight of cellulose by determining the viscosity of cuprammonium (CuAm) sol utions of cellulosic materials, such as wood pulp, cotton, and cotton linters.... Read More

  • Average 30% Cost

  • 100% Confidentiality

  • Free, No-obligation

  • 100% Customer



    ASTM D6188 is a rapid control test used in pulp manufacture. This test applies to a range of cellulose molecular weights because seven sample sizes are defined. ASTM D6188 is suitable for rapid, routine testing of large numbers of samples with high accuracy and precision. This test method is only valid if the sample dissolves completely, without gels. Cotton and high molecular weight pulps are difficult to dissolve. 

    Test Procedure:

    For ASTM D6188, an in-process or finished product sample is selected. In-process samples are washed to remove cooking and bleaching chemicals. Dry samples are bathed with demineralized water. All samples are squeezed to 20 to 40 % consistency as necessary, then passed through a picker. The wet pulp sample is dried with warm air and weighed. The weighed sample is placed in a 120 ml glass bottle, steel shots are added, a vacuum is pulled on the bottle, and 97 ml of cuprammonium (CuAm) solution is added. The bottle is shaken on a shaker which dissolves the pulp sample in the CuAm solution. The dissolved sample is moved to a glass viscosity tube. The tube is mounted vertically with a bright light behind the tube. A glass bead is dropped into the center of the solution. The speed of the fall will be used to determine the viscosity of cellulose. Slower the bead falls, the higher the viscosity. On the tube, there are two marks 20 cm apart. The time is measured for the glass bead to pass between two marks. This time (s) is the uncorrected “as is” cuprammonium ball fall viscosity. The temperature of the solution is determined, and the correction factor for this temperature is multiplied by the uncorrected viscosity of the sample. This gives the “as is” cuprammonium ball fall viscosity value. 

    Video 01: Viscosity by ball drop

    Specimen size:

    The ASTM C6188 test method requires the following:

    1. Cuprammonium solution, containing copper and ammonium hydroxide. 
    2. Potable water.
    3. Reagent (Water) to determine the pH of the film left after acid washing. 


    The viscosity of cellulose is reported. 


    ASTM D6188 is a rapid control test used in pulp manufacture. This test applies to a range of cellulose molecular weights because seven sample sizes are defined. 


    Core Materials Testing Services


    A variety of microscopy and spectroscopy tools available for precise measurements from the nano to the meter scale.

    Metrology Testing Services POPULAR TESTS:

    TEM SIMS Profilometry

    Materials Testing

    ASTM and ISO standard and custom chemical, mechanical, thermal, corrosion tests, etc. for all materials metals, ceramic or polymers.

    Materials Testing Services POPULAR TESTS:

    Nondestructive Testing Electrical Testing Chemistry Analysis

    Product Testing

    Thousands of tests for product quality and reliability under heat, humidity, temperature shock, vibration, drop, electrostatic discharge.

    Product Testing Services POPULAR TESTS:

    Vibration Testing Humidity Testing Accelerated Aging

    Looking for Material Testing?

    We have already delivered 10000+ Material Test results to top companies

      Send us a request

        Process for testing
          STEP 01

          You share material and testing requirements with us

          STEP 02

          You ship your sample to us or arrange for us to pick it up.

          STEP 03

          We deliver the test report to your email.

          Let’s work together!

          Share your testing requirements with us and we will be happy to assist you.

          ddd Just share your testing requirements and leave the rest on us!
          • Free, no-obligation consultation
          • Guaranteed confidentiality
          • Quick turnaround time
          • Hassle-free process


            Let us combine our capabilities to achieve success!!

              idea icon
              Want to connect with an expert before you leave?