exam 3 spring _09 - EMA 3066, Exam 3 April 2, 2009 Name:_...

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EMA 3066, Exam 3 April 2, 2009 Name:______________________________ First Last I have neither given nor received help on this exam.___________________ Signature 1. A polymer with a repeat unit molecular weight of 105 g/mole is 10.0% crosslinked (i.e. a crosslink occurs every 10 repeat units). If the density of this polymer is 1.20 g/cm 3 , determine its modulus in MPa at 25 ˚ C. Note that 1 J = 1 N -m. NOT COVERED FOR FALL ’10 EXAM 3
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EMA 3066, Exam 3 April 2, 2009 2. On a single graph, sketch the stress-strain curves for polyethylene with 30 wt% crystallinity and with 80 wt% crystallinity, clearly showing the differences between the two.
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EMA 3066, Exam 3 April 2, 2009 3. If the stress relaxation modulus for polystyrene is 100 Pa after 10.0 minutes at 150 ˚ C, at what time is the stress relaxation modulus equal to 100 Pa at 160 ˚ C? Take the glass transition to be 100º C.
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EMA 3066, Exam 3 April 2, 2009 4. Draw a viscoelastic model (combinations of springs and dashpots) that will exhibit the
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exam 3 spring _09 - EMA 3066, Exam 3 April 2, 2009 Name:_...

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