Sample Exam I - (a Which polymer will degrade faster...

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(a) Which polymer will degrade faster, poly(D-L lactide) or poly(L- lactide)? Explain why? Polyglycolide has a higher crystallinity because it is hydrophilic. The device with more Polyglycolide will degrade faster because it has a higher crystallinity and because it’s hydrophilic. Drug release would also be faster with a compound that contained more polyglycolide because of hydrolytic ester bonds on its backbone cause it to slowly degrade, leaving room for pores to form and for drugs to slowly diffuse outward into the body. Which of these have a higher melting temperature and why? Polyglycolide has a higher crystallinity and therefore a higher melting temperature. Melting temperature is the temperature at which all crystalline regions melt, and since the polyglycolide is more crystalline, it has a higher melting point due to stronger IMF bonds. (b) Draw a typical stress-strain curve of a solid material and show (a) the elastic region (b) the plastic region (c) yield strength and (d) fracture strength
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