FLAME RETARDANTS These are meant to modify the fire properties of the material

Flame retardants these are meant to modify the fire

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FLAME RETARDANTS These are meant to modify the fire properties of the material. ANTISTATS To reduce the electrostatic charging that can occur when polymeric material surfaces rub against each other. GENERAL PROPERTIES OF POLYMERIC MATERIALS 1) They are resistant both to atmospheric corrosion and to corrosion by many chemical reagents. 2) They have a fairly low relative density – a few will just float in water, but the majority are somewhat more dense. 3) Many are reasonably tough and strong, but the strength is less than that of metals.
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~ Page 55 of 73 ~ However, since the relative density of polymers is low, this means that many have an excellent strength/weight ratio. 4) Most of thermoplastic materials begin to soften at quite low temperatures, and few are useful for service at temperatures above 100 °C. Strength falls rapidly as the temperature rises. 5) Most polymers have a pleasing appearance, and can be coloured if necessary. Some are transparent and completely colourless. GENERAL USES OF POLYMERS In the building construction, polymers have been found very useful for a variety of purposes e.g. fittings, fixtures, structural component parts, etc. In the electrical industry, polymers have been found very useful for insulation materials, etc. The ICT industry has found a lot of good use for polymers. The motor vehicle industry has also increasingly adopted the use of polymeric materials instead of metals for various applications. STRUCTURE OF POLYMERS Polymers involve the combining of many small molecules to give a large molecule involving very large numbers of atoms. The resulting large molecule may be in the form of a long linear chain, a chain with side branches or a cross-linked polymer giving rise to a network of interlocked atoms as shown in Fig. 1 below. The molecular chains of a polymer may be amorphous, completely tangled up in a solid with no order whatsoever. There is however the possibility that the polymer molecules can be crystalline, arranged in an orderly manner within a solid. Because long molecules can easily become tangled up with each other, polymeric materials are often only partially crystalline, i.e. parts of the material have orderly arrangements of molecules while other parts are disorderly.
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~ Page 56 of 73 ~ Fig. 1 Monomer arrangement in copolymers [ edit ] Monomers within a copolymer may be organized along the backbone in a variety of ways. o Alternating copolymers possess regularly alternating monomer residues: [28] [AB...] n (2). o Periodic copolymers have monomer residue types arranged in a repeating sequence: [A n B m ...] m being different from n. o Statistical copolymers have monomer residues arranged according to a known statistical rule. A statistical copolymer in which the probability of finding a particular type of monomer residue at a particular point in the chain is independent of the types of surrounding monomer residue may be referred to as a truly random copolymer [29][30] (3).
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