Chlorinated hydrocarbon / plastic

Polystyrene. Polystyrene [9003-53-6] is a thermoplastic prepared by the polymerization of styrene, primarily the suspension or bulk processes. Polystyrene is a linear polymer that is atactic, amorphous, inert to acids and alkahes, but attacked by aromatic solvents and chlorinated hydrocarbons such as dry cleaning fluids. It is clear but yellows and crazes on outdoor exposure when attacked by uv light. It is britde and does not accept plasticizers, though mbber can be compounded with it to raise the impact strength, ie, high impact polystyrene (HIPS). Its principal use in building products is as a foamed plastic (see Eoamed plastics). The foams are used for interior trim, door and window frames, cabinetry, and, in the low density expanded form, for insulation (see Styrene plastics). 

Polypropylene has a chemical resistance about the same as that of polyethylene, but it can be used at 120°C (250°F). Polycarbonate is a relatively high-temperature plastic. It can be used up to 150°C (300°F). Resistance to mineral acids is good. Strong alkalies slowly decompose it, but mild alkalies do not. It is partially soluble in aromatic solvents and soluble in chlorinated hydrocarbons. Polyphenylene oxide has good resistance to ahphatic solvents, acids, and bases but poor resistance to esters, ketones, and aromatic or chlorinated solvents. 

CHLORINATED HYDROCARBONS Hydfoearbons containing ehlorine atoms, e.g. triehloroethylene. Some of these ehemieals aeeumulate in the food chain and do not readily degrade. Some plastics which contain certain chlorinated hydrocarbons release dioxins into the ah, when burnt at low temperatures. 

Some solvents, including aromatic and chlorinated hydrocarbons, ketones and ethers, will soften the sheet by acting as additional plasticizers. 

Fluorinated rubbers, copolymers of hexafluoropropylene and vinylidene-fluorides, have excellent resistance to oils, fuels and lubricants at temperatures up to 200°C. They have better resistance to aliphatic, aromatic and chlorinated hydrocarbons and most mineral acids than other rubbers, but their high cost restricts their engineering applications. Cheremisinoff et al. [54] provide extensive physical and mechanical properties data on engineering plastics. A glossary of terms concerned with fabrication and properties of plastics is given in the last section of this chapter. 

Caprolactam, a white solid that melts at 69°C, can be obtained either in a fused or flaked form. It is soluble in water, ligroin, and chlorinated hydrocarbons. Caprolactam s main use is to produce nylon 6. Other minor uses are as a crosslinking agent for polyurethanes, in the plasticizer industry, and in the synthesis of lysine. 

Solvent wiping. Rubbers tend to swell by application of solvents and the mechanical interlocking of the adhesive is favored. Although chlorinated hydrocarbon solvents are the most effective, they are toxic and cannot be used toluene and ketones are currently the most common solvents. The treatment with solvents is effective in the removal of processing oils and plasticizers in vulcanized mbbers, but zinc stearate is not completely removed and antiozonant wax gradually migrates to the mbber/polyurethane adhesive interface. Table 27.1 shows the moderate increase in adhesion produced in SBR by MEK wiping. 

Blankenship A, Chang DPY, Jones AD, et al. 1994. Toxic combustion by-products from the incineration of chlorinated hydrocarbons and plastics. Chemosphere 28 183-196. 

Chlorinated compounds PCP, PCBs, PCDD/Fs Manufacture of pesticide and herbicide (D) Wood preservation sites (P) Pulp and paper production (P) Municipal waste incineration (P,D) Plastics, fire-retardants manufacture (P,D) Chlorinated phenols -3.6 Chlorinated hydrocarbons - 2.4 [43, 44]... 

TPE/PVCs are handicapped by the ecological problems involved with chlorine and possibly with some plasticizers a lower elasticity than conventional rubbers, the more so as the hardness increases certain risks of creep, relaxation and permanent set, the more so the higher the temperature rises higher cost than TPOs aromatic and chlorinated hydrocarbon behaviour limited thermal behaviour density fume toxicity and corrosivity in the event of fire tool corrosion risks. 

Fliiorothene. A plastic polymer of trifluoro-chloroethylene, C2F3C1. Resistant to coned acids and alkalies up to 300°F. Swelled by some chlorinated hydrocarbons Ref CondChemDict (1961), 507-R (1971), 208-R... 

Another group of chlorinated hydrocarbons comprises those made from paraffin wax. Major applications are in extreme pressure lubricants and as extenders and plasticizers in surface coatings and in vinyl plastics. The chlorinated waxes were also widely applied in flameproofing cotton fabrics, which led to large consumption by the military. It is believed that current military requirements for flame-resistant fabrics will be met by vinyl sheeting of vinyl-coated textile products, so that the World War II demand for the halogenated waxes will not be repeated. 

Hydrolysis of Chlorinated Hydrocarbons. The production of oxygenated aliphatics by the hydrolysis of chlorinated hydrocarbons includes the synthetic glycerol process and the amyl alcohols process. Glycerol (7) is made from propylene via allyl chloride (CH2 CHCH2C1), and competes with glycerol made from fats and oils for use in dynamite and alkyd resins, as a tobacco humectant and cellophane plasticizer, in cosmetics and pharmaceuticals, and for other applications. Amyl alcohols have been made since 1926 by the alkali hydrolysis of a mixture of amyl chlorides, made by the chlorination of pentanes from natural gasoline. Production from this source far exceeds the supply from the fusel oil by-product of fermentation processes. Amyl alcohol and its derivatives are used mainly as solvents. 

FORMAMIDE. Form amide (meibanamide), HCONHi. is the lirsi member of the primary amide series and is the only one liquid at room temperature. II is hygroscopic and has a faint odor of ammonia. Formamide is a colorless to pale yellowish liquid, freely miscible with water, lower alcohols and glycols, and lower esters and acetone. It is virtually immiscible in almost all aliphatic and aromatic hydrocarbons, chlorinated hydrocarbons, and ethers. By virtue of its high dielectric constant, close to that of water and unusual for an organic compound, formamide has a high solvent capacity lor many heavy-metal salts and for salts of alkali and alkalinc-carth metals. It is an important solvent, in particular for resins and plasticizers. As a chemical intermediate, formamide is especially useful in the synthesis of heterocyclic compounds, pharmaceuticals, crop protection agents, pesticides, and for the manufacture of hydrocyanic acid. 

Polystyrene is an inexpensive transparent plastic which is often used in industry for the fabrication of parts by injection moulding. However, the tougher acrylic plastics are preferable for the construction of laboratory apparatus. Polystyrene is soluble in many organic liquids and, if strain free, may be solvent-bonded by the use of chlorinated hydrocarbons, benzene, or toluene. Special impact-resistant grades are available which are less susceptible to solvents and thus a little harder to solvent-bond than the conventional material. Polystyrene also may be welded. 

Plasticizers include the esters of a few aliphatic and aromatic mono and dicarboxylic acids, aliphatic and aromatic phosphorus acid esters, ethers, alcohols, ketones, amines, amides, and non-polar and chlorinated hydrocarbons. These additives are used in various mixtures. For their separation and qualitative detection, thin-layer chromatography (TLC) is preferred. Usually Kieselgur plates, 0.25 mm thick, activated at 110°C for 30 min, in the saturated vapor are used. Methylene chloride and mixtures of diisopropyl ether/petether at temperatures between 40 to 60°C have been successfully used as the mobile phase. Refer to Table 1. 

PCBs are mixtures of chlorinated hydrocarbons. Regarding the source of contamination, they can be divided into two main groups intentional (commercial products) and unintentional (by-products of combustion, such as an incinerator trace amounts of PCBs have been reported in agricultural chemicals or chemical products as impurities) (UNEP Chemicals, 2002). PCBs were produced commercially in the United States from 1929 to 1977. Due to their chemical inertness, heat resistance, a high dielectric constant and nonflammable properties, they have been used extensively for a variety of industrial purposes, such as dielectrics in transformers and large capacitors as heat exchange fluids and in plastics (WHO, 1993). 

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