Homework #9 Solutions 1. If you want to recycle the polymer, it must be able to form a liquid. If you want it to form a liquid, it can't be thermoset; it must be thermoplastic. Thermoset polymers are crosslinked. The crosslinking is caused by using a monomer with functionality greater than 2. Therefore, to get a recyclable polymer you should only use monomers with functionality equal to 2. Therefore, you can not use monomer b, which has f=3. You can use any combination of the other three monomers: a, c, and d; a and c; a and d; or c and d. 2. a.The amount of heat released tells you how many groups did not react during the 30 minutes of cure: %3862100cure%%62100xg/kJ85.0g/kJ53.0unreacted%=−===b.This is before both gelation and vitrification, so it is a liquid. c.Depending on what the Tg of the monomer is, it could be either a liquid or an uncrosslinked glass. 3. (a)Organic materials with extended π-conjugationunits may exhibit semiconducting behavior. [The extended π
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