Part Two. Foam is a substance that is formed by trapping many gaseous bub­bles in a liquid or solid

Paints

Part One

Foam is a substance that is formed by trapping many gaseous bub­bles in a liquid or solid. Liquid foams are used in extinguishing fires, especially oil fires. Solid foams form an important class of lightweight cellular engineering materials. These foams can be clas­sified into two types based on their pore structure: open cell structured foams and closed cell foams.

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Open cell structured foams contain pores forming an intercon­nected network which is relatively soft. If filled with air, this foam could be a good insulator.

Closed cell foams do not have interconnected pores. [Normally, the closed cell foams have higher compressive strength due to their structures; they are also denser, require more material, and are more expensive to produce.]⁰ The closed cells can be filled with a specia­lized gas to provide improved insulation.

More recently synthetic foam has been used in combination with structural materials, such as concrete. [It is usually used as part of a structural insulated panel where the foam is sandwiched between wood and cement or insulated concrete forms where concrete is sand­wiched between two layers of foam.]° All types of foam are also used as core material in sandwich structured composite materials. (1 050 п.зн.)

[Paints is any liquid, liquefiable, or mastic composition which after application to a substrate[3] in a thin layer is converted to an opaque solid film. ]⁰ Cave paintings drawn with red and yellow ochre, hema­tite, manganese oxide, and charcoal may have been made by early Homo sapiens as long as 40,000 years ago.

|Pigments are granular solids incorporated into the paint to contri­bute colour, toughness, texture or simply to reduce the cost of the paint.]⁰ They can be classified as either natural or synthetic types. Hiding pigments, in making paint opaque, protect the substrate from the harmful effects of ultraviolet light.

[Fillers are a special type of pigment that serves to thicken the film, support its structure and just increase the volume of the paint.]⁰ Fillers are usually made of cheap and inert materials, such as earth, talc, lime, clay, etc. Some paints contain large proportions of pig­ment/filler and binder.

[Binder, commonly referred to as vehicle, is the actual film form­ing component of paint.]⁰ It is the only component that must be present; other components are included optionally, depending on the desired properties of the cured film. [The binder imparts adhesion, binds the pigments together, and strongly influences such properties as gloss potential, exterior durability, flexibility, and toughness.]⁰

Paint can be applied as a solid, a gaseous suspension (aerosol), or a liquid. Techniques vary depending on the practical results desired. As a solid, the paint is applied as a very fine powder, and then baked at high temperature. This melts the powder and causes it to stick to the surface. In the liquid application, paint is applied directly using brush­es, paint rollers, blades, etc. Paint application by spray is the most popular method in industry.

*Substrate is a substance or layer that underlies something, or on which some process occurs. (1 600 п.зн.)

4. Переведите предложения [...]⁰ письменно.

5. Закончите предложения по темам.

A.

■ Foam is a substance...

■ Open cell structured foams...

■ Closed cell foams...

■ More recently synthetic foam has been used...

■ It is usually used as part of a structural insulated panel where the foam...

B.

■ Paint is any liquid, liquefiable, or mastic composition...

■ Pigments are granular solids incorporated into...

■ Fillers are a special type of pigment that serves...

■ Binder is the actual...

■ As a solid, the paint is applied...

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