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quiz8spr2000 - ~ ENGSC 3313 Spring 2000 Answer anv 4...

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Quiz 8 Name ENGSC 3313, Spring 2000 Answer anv 4 Questions only, 1 point each A polypropylene molecule, HO-(-C3H6-)SOO-OH, was initiated and terminated with free radicals. Of the ~ mass of the molecule, what fraction represents the contribution of the end groups? Total mass = 2(1 + 16) + 500[3 x 12) + (6 x 1)] = 21,034 amu Mass of End Groups = 2(1 + 16) = 34 aInU fr .34 amu 3 actIon = 21.034 amu = 1.6 x 10- , =0.16% Calculate the polydispersivity index (pDI) for the polymer of the following data. 2, G 5 7 0.15 H 6 8 0.20 c 5 3 0.06 Fraction Ratio of No. ofMolecules Mean weight (units of 104) Weight Fraction F 10 6 0.26 Mw M 5.90 5.465 ~ ~~ Pill= = N There are applications, such as shopping carts where polypropylene would be the better choice economically and design-wise based on mechanical properties, Qill polyethylene has to be used because such carts are sold worldwide, including Canada. Explain! 3. pp has too high a glass transition temperature (~ -1 0°C) so would be brittle when carts see the outdoors in Canadian -and Dakota, etc. -winters. Wheels would see impact conditions in service and would fracture.
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