- B 10 Pts As Your Advisor Has High Requirements He Wants To Use Low Dispersity Polymers Only He Asks You To Synthes 1 (193.96 KiB) Viewed 64 times
- B 10 Pts As Your Advisor Has High Requirements He Wants To Use Low Dispersity Polymers Only He Asks You To Synthes 2 (75.82 KiB) Viewed 64 times
(b) (10 pts) As your advisor has high requirements; he wants to use low dispersity polymers only. He asks you to synthesize a new batch targeting M,=12,000. You synthesized the polymer (the chemical structure of your product is shown below) and get its proton NMR spectra in using CHCl3 solvent to determine its Mn. The integrated areas corresponding to different protons in the structure are listed in the table below: Proton a b Integrated area 34.88 21.54 9.89 22.07 9.00 C d e Ds Note the solvent peak and H2O peak in the spectra, which can artificially cause high integration values for peak a and peak d, respectively. Also, it is known that the peak c has a slightly lower integration value that is postulated to be due to an upfield shift of some of the repeat units near the polymer terminus. Thus, it is best to use peak b. Calculate M, for the polymer you synthesized (neglect the end group contribution). Show all your work. Was your synthesis successful? What is the error % if you use the peak a, c and d for your M, determination. на на -R сня "Н,С- -01 CHE HRI HD H4 НА H n CHCI, TMS PPM
maj (a) Suppose your lab has very low-dispersity polystyrene (C3H8), batches with the following characteristics: Polymer 1: Mn: 5,000 g/mol Polymer 2: Mn: 30,000 g/mol In your project, you needed to use an intermediate molecular weight of polystyrene of M=12,000. You noticed that this intermediate molecular weight is not available in your lab, and, for some reason, you do not want to synthesize it. So you want to mix the two polymers available to get the desired intermediate Mr. Before talking to your advisor about this plan, you need to know the dispersity of this mixture Calculate the weight fraction of Polymer 1 you should have in the mixture and the resulting dispersity.