Structural closed cell foam is a type of material consisting of internal closed spheres or pores that form a type of cell network. It is created when gas bubbles are formed as the material solidifies from a liquid state and the fact that these cells are not interconnected makes the material strong, stiff, and flexible at the same time. This unique internal structure provides the foam with enhanced properties and the versatility to be used in a number of applications. Since the cells are not connected to each other, they can be filled with various types of gases during their formation, providing extra mechanical abilities.
The application range is very wide. These light and rigid closed cell foams are mainly used as thermal insulators and packaging materials for electronic and computer components, clothing, metal products, furniture, food, plants and any kind of goods. Other major application fields are: marine equipment, aerospace, construction, and industrial production (containers, crafts, etc)
Some of the basic types and uses of closed cell foam are described below.
Types and Specific Uses
Aerogel: This is a silicon-based foam that consists of 99.8% air, which makes it the lightest bulk material available (density of 3 mg/cm3). Aerogel's melting point is almost 1,200 °C, it can endure extreme temperatures and has remarkable insulatory and fire protecting properties. These properties make it suitable for firefighter equipment and astronaut spacesuits. NASA has also used it as a protection thermal shield for space instruments and equipment. Aerogel is known as frozen or blue smoke, since it feels like hard plastic.
Latex: This is a natural material that comes from rubber trees and its basic function is to protect the plant against fungi, bacteria and browsing animals. Most common applications involve the manufacturing of pillows, rubber gloves, condoms, sealant materials and chewing gum. It is also used as a paint binder and even as a source for opium.
Polyisocyanurate: The basic characteristic of polyisocyanurate is the high thermal resistance that makes it very effective for insulation applications, a common feature among all closed cell foams. It is mostly found in the interior of vehicles, ships, aircrafts and even residents. A drawback in the case of polyisocyanurate is the high installation costs.
Airex or FloTex foam: This is a foam of extremely high fire resistance and low moisture absorbency, properties that make it suitable for the construction of cockpit doors and insulation of aircraft panels.
Polystyrene: A polymer that can be manufactured by petroleum and has a variety of desirable properties. It can be colorless or take on various colors, it is hard, inflexible and most importantly inexpensive. Polystyrene can be cast into molds and easily take any particular form, a fact that makes it suitable for a variety of applications. One of the most popular types is the expanded polystyrene (EPS), a very light material that consists of 5% polystyrene and 95% air. The latter is mostly used as a packing material for cushioning fragile items inside boxes, insulation, coffee cups, food containers etc. It is also known under the trade name Styrofoam.
Polychloroprene: Also known with the trade name Neoprene, it is actually the polymer of chloroprene. This material has advanced rubber properties compared to natural rubber. It is mostly used in oil and gasoline tube manufacturing due to its high oil resistance. Other applications include automobile belts, wet suits, adhesives, gaskets, hoses and corrosion-resistant coatings.
Polythene foam: Polyethylene or polythene is another inexpensive plastic, obtained through the polymerization of ethylene or ethene. It is odorless, ozone friendly and inert to grease, solvent and water. The most frequent use involves packaging for the food industry, although it is often found in marine equipment due to its ability to float in water (buoyancy).
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