Lab 2 questions answered

1) What is the difference between t and t0?  In the handout, it says in the procedure that t0 is the average time the solution took to reach the second point (step 8), yet it in the calculations section (step 1) it says t is the average flow time.  Is t the value for flow time in one trial, and t0 the average flow time of all the trials?

A) to is the flow time of the solvent without any polymer. It is the background. This should be your water reading. t is the value of the polymer solutions.

2)  When you ask us to plot viscosity vs. shear strain rate and then fit the data with the appropriate equation.  What type of equation are you looking for?

A) There are a number of equations on the back of the lab. But you should try to fit it to the power law

3)  Same problem for the plot of viscosity vs. temperature.  Also, which viscosity value should we use for each temperature?  Should we take an average viscosity for each temp?

A) Take the shear vs viscosity and have 3 graphs for each of the temps. Then take the average Newtonian viscosity vs temp. 

4)What literature data should we use for PP in part I of the lab.

A) I did a google search and this was one of the many hits:http://www.atsrheosystems.com/ats%20notes/polypropylene%20rheology-qc.pdf

Check it out to see if it helps.