Foaming, plastics

FMN See flavin mononucleotide, foamed plastics See cellular plastics. 

Foam controllers Foamed lonomers Foamed materials Foamed plastic Foamed plastics... 

Foam-injection molding Foam plastic sheathing Foam products Foam regulators Foam rheology... 

The use of CFCs as foam blowing agents has decreased 35% from 1986 levels. Polyurethanes, phenoHcs, extmded polystyrenes, and polyolefins are blown with CFCs, and in 1990 the building and appHance insulation markets represented about 88% of the 174,000 t of CFCs used in foams (see Foamed plastics). 

Cellular polymers have been commercially accepted in a wide variety of appHcations since the 1940s (10—19). The total usage of foamed plastics in the United States has risen from 441 X ICf t in 1967 to 1.6 x 10 t in 1982, and has been projected to rise to about 2.8 X 10 t in 1995 (20). 

A cellular plastic has been defined as a plastic the apparent density of which is decreased substantially by the presence of numerous cells disposed throughout its mass (21). In this article the terms cellular plastic, foamed plastic, expanded plastic, and plastic foam are used interchangeably to denote all two-phase gas—soHd systems in which the soHd is continuous and composed of a synthetic polymer or mbber. 

One ASTM test procedure has suggested (24) that foamed plastics be classified as either rigid or flexible, a flexible foam being one that does not mpture when a 20 x 2.5 x 2.5 cm piece is wrapped around a 2.5 cm mandrel at a uniform rate of 1 lap/5 s at 15—25°C. Rigid foams are those that do mpture under this test. This classification is used in this article. 

The properties of commercial rigid foamed plastics are presented in Table 2. The properties of commercial flexible foamed plastics are presented in Table 4. The definition of a flexible foamed plastic is that recommended by the ASTM Committee D 11. The data shown demonstrate the broad ranges of properties of commercial products rather than an accurate set of properties on a specific few materials. Specific producers of foamed plastics should be consulted for properties on a particular product (137,138,142). 

Table 2. Physical Properties of Commercial Rigid Foamed Plastics ...

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