The Art of Mixtures

By: Jennings Bryson, Suzanne Hodges & Kyle Oldham

What Makes Paint a Mixture

• Paints are a type of mixture called a colloid. • Paint contains several components, including

the pigment, a solvent, a binding medium, and additives.

Paint Ingredients

• Pigment - gives the paint its color• Binding medium - a liquid polymer that

hardens to form a continuous layer when the paint dries

• Solvent - dissolves the binding medium and makes the paint more fluid.– (polymer: a large molecule)

• Additives- small amounts of substances modifying the paint properties

Physical Change

• Emulsion paints are water-based. Their solvent is water, and it dries when the water evaporates.– Physical change

Chemical Change

• The pigments in oil paints are dispersed in oil, which may itself be dissolved in a solvent.

• The solvent evaporates away when the paint dries. This leaves the pigment and oil behind. The oil oxidises to form a hard film. – This happens because the oil reacts with oxygen in the air.– Chemical changehttps://www.youtube.com/watch?v=Qc5snqAR8cI

http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway/carbon_chemistry/paintsrev1.shtml

Chemical or Physical

• Is mixing two different colors of paint a chemical or physical change?– It is a physical change because mixing the two

paints does not make a different substance, it simply makes a different color.

http://www.substech.com/dokuwiki/doku.pjp?id=composition_of_paintshttp://www.bbc.co.uk/schools/gcsebitesize/ocr_gateway_pre_2011/rocks_metals/1_paints_pigments2.shtml

Oil Paint Facts

• Most oil paints are undercoats or primers that will always come in a metal can

• The paint itself is flammable because it contains petroleum distillates(paint thinner)

• The vapor it gives off, volatile organic compounds, VOCs, can be very dangerous.

Oil Paint facts cont.

• Extra fact: – Before 1978, many paints’ pigments contained so

much mercury, that the neurotoxins were harmful to developing children, the adult brain, nervous system, and virtually every organ.

• Now, the danger of the mercury or VOCs subside after the paint dries.

• www.dejeronimopainting.com