User:Klare Lazor/Notebook/Chem-496-001/2013/02/15

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Objective

1) Crosslink Monday's Films: This was done with the same procedures as always: Placed in 0.7M HCl (70 degrees) for 1hr then into 1.68g/100mL Sodium BiCarbonate 15 minute then soaked in water for at least an hour. This was done in the hood.

2) Remove and dry the films crosslinked on monday on paper towels in the hood.

3) Preparing PVOH and 3-Chloro-2-Hydroxypropyltrimethylammonium chloride reacted crystals. Procedure and Calculations below:

Description

Calculations for the quaternary ammonium in pvoh synthesis

From previous calculations, there are 1.369E22 OH groups in 1g PVOH MW22000. We want to prepare 2g, so it's actually 2.738E22 OH groups. We want to prepare a solution of the 3-Chloro-2-Hydroxypropyltrimethylammonium chloride such that it reacts w 10% of OH groups in 2g of PVOH in a 1:1 reaction. 2.738E22 OH groups x 0.1 = 2.738E21 molecules of 3-Chloro-2-Hydroxypropyltrimethylammonium chloride react w 10% of OH groups in 2g PVOH. 2.738E21 molecules of 3-Chloro-2-Hydroxypropyltrimethylammonium chloride / 6.022 molecules per mole = 0.0045 moles 3-Chloro-2-Hydroxypropyltrimethylammonium chloride. 0.0045 moles 3-Chloro-2-Hydroxypropyltrimethylammonium chloride x 188.1g/mole 3-Chloro-2-Hydroxypropyltrimethylammonium chloride = 0.855g of 3-Chloro-2-Hydroxypropyltrimethylammonium chloride would react w 10% of the OH groups in PVOH.

4 sets of 2g PVOH were left to dissolve (as much as possible on a stir plate) in 5mL 0.2M NaOH for 30 minutes. 0.855g of 3-Chloro-2-Hydroxypropyltrimethylammonium chloride was left to dissolve in 5mL 0.2M NaOH for 30 minutes.

So... we want solutions of PVOH and 3-Chloro-2-Hydroxypropyltrimethylammonium chloride in 10 mL of 0.2M NaOH such that 3-Chloro-2-Hydroxypropyltrimethylammonium chloride reacts with 0.01%, 0.1%, 1% and approximately 10% of the OH groups in 2g PVOH. Thus, since our "stock" solution of 3-Chloro-2-Hydroxypropyltrimethylammonium chloride is 10% and 0.885g in 5mL NaOH (0.2M). 0.855g/5mL=0.171g/mL 3-Chloro-2-Hydroxypropyltrimethylammonium chloride "stock" solution...

0.01%: x/0.855g=0.01%/10%, x=0.000855g. 0.000855g/0.171(g/mL)= 0.005mL of the "stock" 3-Chloro-2-Hydroxypropyltrimethylammonium chloride solution. Thus to make our 0.01% 3-Chloro-2-Hydroxypropyltrimethylammonium chloride:PVOH, would require the 2gPVOH dissolved in 5mL NaOH 0.2M + 0.005mL of the "stock" 3-Chloro-2-Hydroxypropyltrimethylammonium chloride filled to 10mL NaOH 0.2M [4.995mL extra NaOH 0.2M]. Similarly...

0.1%: Required the 2gPVOH dissolved in 5mL NaOH 0.2M + 0.05mL of the "stock" 3-Chloro-2-Hydroxypropyltrimethylammonium chloride filled to 10mL NaOH 0.2M [4.95mL extra NaOH].

1%: Require the 2gPVOH dissolved in 5mL NaOH 0.2M + 0.5mL of the "stock" 3-Chloro-2-Hydroxypropyltrimethylammonium chloride filled to 10mL NaOH 0.2M [4.5mL extra NaOH].

To make the "10%" solution, we used the 4.445mL left over "10% stock" 3-Chloro-2-Hydroxypropyltrimethylammonium chloride solution. To solve for the actual percentage this makes... (4.445mL)(0.171g/mL 3-Chloro-2-Hydroxypropyltrimethylammonium chloride) = 0.760095g 3-Chloro-2-Hydroxypropyltrimethylammonium chloride (0.760095g)/(0.855g)=x%/10% x=8.89% so, the solution is actually 8.89% of PVOH OH groups reacting w 3-Chloro-2-Hydroxypropyltrimethylammonium chloride.

The PVOH and 3-Chloro-2-Hydroxypropyltrimethylammonium chloride wasn't dissolving properly after they were combined (the PVOH never really dissolved in the first place) so the solutions were moved to the hood to dissolve on the hot plate.

Observations of cross linked films

  • Alot better than previous films with higher mw.
  • flatter less brittle, less bubbles
  • 1% seems the best
  • 10% to fragile to little crosslikning
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