Foamed plastics classes

In terms of fire safety, there are no fire resistance requirements and all interior surfaces must comply with the FSI of 200 in the Steiner tunnel test, ASTM E 84,114 or a radiant panel index of 200 in the radiant panel test, ASTM E 162.55 Thermal insulation materials, other than foam plastics, must meet an ASTM E 84 Class A requirement (i.e., FSI < 25 and SDI < 450) and loose-fill insulation must meet the same requirements as the building codes, which are mostly based on smoldering tests (as the materials tend to be cellulosic). Foam plastic insulation must be treated as in the building codes as well (see Table 21.13) it cannot be used exposed (expensive foam that meets the NFPA 286 test is not used in manufactured housing) and must meet an ASTM E 84 Class B requirement behind the thermal barrier. 

Examples of Class IV products are small appliances, typewriters, and cameras with plastic parts plastic-backed tapes and synthetic fabrics or clothing. An example of packing material is a metal product in a foamed plastic cocoon in a corrugated carton. 

Much of this growth has been recorded periodically in Modern Plastics (particularly every January), the Journal of Cellular Plastics, and the annual "Modern Plastics Encyclopedia." Collection of information in textbook form began with Ferrigno in 1967, Banning in 1969, and Frisch and Saunders in 1972-73. More recently Meinecke and Clark, and most recently Hilyard, have made notable contributions to the understanding of foam properties. This chapter will summarize the processes by which foamed plastics are produced, the major classes, the relationships between foam structure and properties, the leading polymers used in foam production, and their major applications and markets. 

PUR are a broad class of highly cross-linked plastics prepared by multiple additions of poly-functional hydroxyl or amino compounds. Typical reactants are polyisocyanates [toluene diisocyanate (TDI)] and polyhydroxyl molecules such as polyols, glycols, polyesters, and polyethers. The cyanate group can also combine with water this reaction is the basis for hardening of the one-part foam formulations. 

Surfactants used as lubricants are added to polymer resins to improve the flow characteristics of the plastic during processing they also stabilise the cells of polyurethane foams during the foaming process. Surfactants are either nonionic (e.g. fatty amides and alcohols), cationic, anionic (dominating class e.g. alkylbenzene sulfonates), zwitterionic, hetero-element or polymeric (e.g. EO-PO block copolymers). Fluorinated anionic surfactants or super surfactants enable a variety of surfaces normally regarded as difficult to wet. These include PE and PP any product required to wet the surface of these polymers will benefit from inclusion of fluorosurfactants. Surfactants are frequently multicomponent formulations, based on petro- or oleochemicals. 

Polyurethanes, as a class of materials, are one of the most versatile available. By varying the reactants, their amounts and the reaction conditions, one can obtain millable elastomeric gums, hard rigid plastics, reactive liquids, and foams. The versatility is such that it is very difficult to provide a brief summary. 

This particular manufacturer created a composite panel consisting of a glass-fiber reinforced plastic outer shell backed with a rigid polyurethane foam. The product looks like a cluster of hand split wood shakes. When installed, the panels interlock and look exactly like a shake shingle roof to the casual observer. These panels have been tested and qualify as a Class A built-up roof covering. In addition, they provide a much greater resistance to the transmission of heat than wood shake shingles. The panels are fast and easy to install and quite durable. 

This class of materials includes inhibited greases produced by impregnation of a polymer thickener into liquid oils foamed by the inhibitor vapors. The polymer forms a skeleton that, under high loads, imparts the properties of a solid to the lubricant p < 0.1 — 2.0 kPa). Thanks to the high viscosity of the foamed oil, it localizes in the polymer skeleton cells so that the system becomes quasi-compatible. It can be roughly referred to as a plastic, although showing the properties of both solid and liquid polymer materials. 

In Germany, Otto Bayer attempted to circumvent the nylon patent, and in doing so discovered that molecules called diisocyanates reacted with another class of substances called diols to make polymers. Furthermore, Bayer found that, if the reactants were contaminated with a trace of water, the water would react with some of the diisocyanate to form carbon dioxide bubbles. As the bubbles escaped, they caused the plastic to foam. 

Handbook of Polymer Testing provides in one volume that comprehensive coverage of physical test methods for polymers. The properties considered cover the whole range of physical parameters, including mechanical, optical, electrical, and thermal as well as resistance to degradation, nondestructive testing, and tests for processability. All the main polymer classes are included rubbers, plastics, foams, textiles, coated fabrics, and composites. For each property, the fundamental principles and approaches arc discussed and particular requirements and the relevant international and national standards for the different polymer classes considered, together with the most-up-to-date techniques. 

A rigid foam is defined as one in which the polymer matrix exists in the crystalline state or, if amorphous, is below its Tg. Following from this, a flexible cellular polymer is a system in which the matrix polymer is above its Tg. According to this classification, most polyolefins, polystyrene, phenolic, polyycarbonate, polyphenylene oxide, and some polyurethane foams are rigid, whereas rubber foams, elastomeric polyurethanes, certain polyolefins, and plasticized PVC are flexible. Intermediate between these two extremes is a class of polymer foams known as semirigid. Their stress-strain behavior is, however, closer to that of flexible systems than to that exhibited by rigid cellular polymers. 

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