User:Elizabeth Ghias/Notebook/Experimental Chemistry/2013/02/11

Objective

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.

Description

Crosslinking

1. Determined the concentration of HCl needed, by determining the concentration of H₂SO₄

Preparation of Lower Weight PVOH Films

1. Measured out 6 1 g samples of PVOH (MW = 22,000)
2. Prepared a solution of 0.22 g phenol in 10 mL water.
3. Dissolved the PVOH samples in 30 mL water (in 100 mL beakers)
4. 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

1. Measure out 20 mL 0.50 NaOH
2. Add to 30 mL water
3. Save for use on Friday.

Data

No data was collected today.

Notes

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.