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Environmental/Exposure Testing of Various Polymer Coatings

Objective:

The purpose of this activity is to:

gain an understanding of exposure on various polymeric coatings
gather data from extended observation to make conclusions/comparisons
use data to determine applicability of coatings in business/industry/environment

Materials:

Acetic acid solution, pH 5.0 (acid rain)
OR
2% NaCl solution (ocean water)
OR
Acetic acid solution, pH 6.5 (saliva)
OR
Ammonia solution, pH 10 (household cleaners)
Disposable plastic pipette
Labeled Coated glass slides (one for each coating to be studied)
Tray
Thermometer
White copy paper
Clear tape

Saftey:

Manufacturers provide instruction for the use of their products, and these instructions should be followed completely. Protective gloves and lab coats should be worn when preparing and handlingthe coated glass slides and safety glasses should be worn at ALL times.

Procedures:

Obtain your solution (each group should use a different solution) and the rest of supplies from teacher.
Make an Initial Observations Data Table of the physical characteristics of each coating before applying any of the solutions (your teacher should have an example).
Using tape, secure white copy paper to your tray to minimize differences in reflected light.
Also, secure each slide to the paper now covering the tray. Make sure slides are coating-side up. Label your tray with your names, the class period, and which solution you are using.
After making initial observations and preparing slides and tray, add 0.1mL of solution to the center of each coating sample slide. Note whether the solution is absorbed or repelled and compare the drop size among the different coatings. Record temperature.
Place slide tray in a sunny windowsill. (trays should be clearly labeled to avoid future complications)
Every 24 hours after the initial test, observe the effect the solutions had on the coatings. Enter data into a separate data table for observations after each test (your teacher should have an example of such a data table).
Following observations, reapply 0.1 mL of test solution to each sample on the tray taking care to keep the newly introduced amount of solution in the same proximity/area as in the prior test.
Repeat this procedure for approximately two weeks. The longer the experiment is maintained the more pronounced the effects of the environmental test.

Conclusions:

Compare your data and observations withthat of the other groups. How did the coatings perform?

Was there a coating that was clearly superior in most or all of the tests?

Was there a coating that was clearly inferior in most or all of the tests?

Name some physical characteristics which have obviously played a role in coating performance.