CHEM 3090 Lecture Notes - Dispersity, Due Date, Nylon 66
6 May 2014
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March 3rd, 2014 (by 9:30am) before class starts. Please, write your name and student id on your paper. Unstapled work won"t be accepted and will result in a mark of 0%. Unfortunately, the new catalyst also seems to co- produce the corresponding cyclic tetramer, with a tg of 80 c. Assume the length of the ethylene unit to be about 1. 78 . 3) a pet sample with a tg and a tm of 69 and 267 c, respectively, is heated to. Explain why: high- density polyethylene (no branching) is dissolved at elevated temperature. It is then melted and cooled slowly to room temperature to yield a different kind of material. Why is it that atactic polypropylene does not melt at all. 7) (optional for receiving 100% on this problem set. Figure below, taken from j. poly. 1978, 16, 1229, tg of nylon- . 6 decreases by about 25% when the polymer absorbs 10 wt % water.
