To crosslink the films prepared last class, to test the effects of using a lower molecular weight PVOH on the film, and to prepare a 0.2 M NaOH solution for use next class.
- Determined the concentration of HCl needed, by determining the concentration of H2SO4
Preparation of Lower Weight PVOH Films
- Measured out 6 1 g samples of PVOH (MW = 22,000)
- Prepared a solution of 0.22 g phenol in 10 mL water.
- Dissolved the PVOH samples in 30 mL water (in 100 mL beakers)
- Once the PVOH had dissolved, the corresponding amounts of phenol solution were added (1% film = 1 mL, 0.1% =
NaOH Calculations and Preparation
- need to prepare 50 mL of a 0.2 NaOH solution from a 0.5 N NaOH soln.
(0.5 moles/L)(X) = (0.2 moles/L)(0.05 L) → X = 0.02 L = 20 mL
- Measure out 20 mL 0.50 NaOH
- Add to 30 mL water
- Save for use on Friday.
No data was collected today.
Description of Films Prepared Last Class
- 1% film prepared in Erlenmeyer flask looked the best, was uniform, etc.
- 0.1% and 9% films were not uniform, had lumps of PVOH
- The poor quality of the films was attributed to the high molecular weight of the PVOH.