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    CM4655 ASSIGNMENT 3:  TORSIONAL PLATE RHEOMETRY

    DUE:  Thursday, November 18, 2004 5pm to me or in my mailbox in 203 Chem Sci (paper) or midnight (PDF).  Note that on the WE network you can produce a PDF file by printing the file to the printer  \\printer1\pdf.  The  PDF file will be emailed to you.

    REPORT OBJECTIVE

    For your assigned polymer, please measure and report on the true steady shear viscosity at three different temperatures, as measured with the Bohlin C-VOR torsional parallel plate rheometer in 309A of the Chemical Sciences Building.  Please also report G' and G" as a function of frequency for those three temperatures.

    EXPERIMENTAL NOTES

    1. Follow the rules in the safety handout, in the Bohlin C-VOR operating instructions, and in the CM Department Safety Manual at all times.
    2. If you have questions about operation of the Bohlin, please contact me (fmorriso@mtu.edu; office 7-2050; home 487-9703; cell 1-906-458-8401). If there is an emergency, dial 123 from a campus phone or 911 from any phone including the lab cell phone (906-281-2084).
    3. Do not exceed 220oC.  Polymers degrade at high temperatures.  For the lower range of temperature use 20oC above the material’s glass transition temperature or melting temperature.  You do not want to measure too close to Tg or Tm since the viscosity will be very large there and there is danger of damage to the transducer.
    4. Explore as wide a range of shear rate as possible; explain in your report what experimental factors limit the range of shear rate that is available to you.
    5. Check your data for reproducibility, and be sure to discuss how you did this in your report.  Include all data in your report; if you believe any data are incorrect, explain this in your report.
    6. Be sure to degas your polymer.  To do this, place the molded samples in the vacuum oven overnight.  Only take out of the vacuum oven the samples that you need for the experiment you are currently running; store all degassed polymer either in the vacuum oven under vacuum, in a desiccator with fresh desiccant, or in an airtight plastic bag.
    7. Purchase a bound laboratory notebook.  Use the notebook to keep track of each run, including conditions of the run, conditions of the polymer, and all observations related to the equipment.  Turn in your laboratory notebook along with your report or during the first class period after the report is turned in.  You may use the lab notebook from the first report (I will return it to you).

    REPORT NOTES

    1. Your report may be as short as you can make, it providing you meet the objective you were given.
    2. Please include an executive summary, an introduction, an experimental section (where you describe the instruments you used and how you handled your materials in the laboratory), a results and discussion section (where you describe what experiments were carried out and how they turned out), a summary, and a reference list.  You may look at articles in the journal Macromolecules for guidance on how these sections are typically structured.
    3. In your discussion section, be sure to mention any experimental difficulties you encountered and any observations you have.  Be sure to describe any changes that occur in the sample between when you load it and when you remove it from the instrument. 
    4. If you have any suggestions for laboratory improvements, please include them in the discussion section of your report.
    5. Please include your raw data in an appendix to the report.  Remember, only put things into the appendix that can be separated from the report.  The report (without appendices) should stand alone.
    6. You may submit your report as a printout delivered to me or to my CM department mailbox in room 203 Chem Sci or as a PDF file emailed to me as late as midnight on the due date.