|Gravimetric Determination of the Nonvolatile Content of Paint|
This activity provides the student with an introduction to gravimetric procedures and at the same time introduces the basic components of paints. A small amount of paint is weighed into one of two aluminum foil weighing dishes. Nesting the second dish in the first covers the paint sample, making it possible to weigh the sample without weight loss due to evaporation of volatile components, which begins to occur as soon as the paint is exposed to the atmosphere. The paint sample is then spread into a film by pressing the nested (second) dish against the first. The two dishes are separated and the paint films on them are dried in a forced-air oven. After 30 minutes of drying, the dishes are reweighed. The mass data is used to calculate the percent nonvolatile matter in the paint sample.
Historical Background of Paint and Coatings
Provides historical background information on this topic. No laboratory activity is included.
Making a Surface Coating
In this activity students prepare a nonaqueous surface coating by first making a polymeric resin and then adding an organic solvent. The product is a basic varnish that hardens by loss of organic solvent to the air. A simple paint can be made by adding pigment to the varnish. An oleoresinous varnish can be made by adding an oil, such as linseed. Certain properties of the varnishes and paint film can be tested and compared: drying time, hardness, flexibility, and degradation of film or underlying substrate due to long-term exposure to ultraviolet radiation.
Manufacturing Paint and Coatings
Provides background information on this topic. No laboratory activity is included.
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|Terrific Science, Cincinnati, Ohio|