Vinyl chloride polymers derived from

By far the greatest part of PVC production across the world is now made by the suspension process. Vinyl chloride monomer (derived from a reaction between ethylene (derived from oil) and chlorine (derived from common salt) is dispersed in deionised water with the help of small quantities of chemical dispersants and polymerisation initiators (typically peroxide compounds). At moderately raised temperature (50 C) and pressure (0.7 MPa) polymerisation proceeds and the polymer can be removed from the resulting slurry by de-watering and steam stripping the unconverted vinyl chloride monomer. 

An irregular polymer derived from vinyl chloride (ehloroethene), the eonstitutional units of whieh are linked both head-to-tail and head-to-head ... 

More than 500 million pounds of poly(vinyl acetate) (PVAc), poly(vinylidene chloride), and their copolymers and polymers derived from them are produced annually in the United States. PVAc does not have sufficient strength for producing the types of products obtained from polyethylene, polystyrene, and poly(vinyl chloride) since it is noncrystalline and has a Tg of only 28°C. However, poly(vinyl acetate) (XLI) and its copolymers find uses as... 

Production of all types of vinyl resins, exclusive of plasticizers and fillers, during 1941 to 1950 are presented in Figure 2. These totals are for production of all polymers customarily classified as vinyl resins, including polyvinyl chloride, copolymers of vinyl chloride with vinyl acetate or vinylidene chloride, or modified polymers derived from them. However, the principal monomeric raw material for this field of resins is vinyl chloride. 

The pioneer in the field of truly synthetic fibres was Carothers, who demonstrated that two comparatively simple compounds derived from phenol, namely, hexamethylenediamine and adipic acid, could be caused to polymerize to form a potentially fibrous polymer. This was spun into yarn which was successfully placed on the market as nylon. Shortly afterwards ethylene glycol and terephthalic acid were condensed to a polymer from which Terylene or Dacron was made. Ethylene is a by-product in the cracking of petroleum and is the starting point in the manufacture of vinyl chloride and acrlyonitrile, from which Vinyon and the various polyacrylonitrile fibres respectively are spun. 

Photosensitized crosslinking of polymers has been the subject of numerous publications [l - 30], concerned mainly with poly(ethylene), poly(vinyl alcohol), various vinyl copolymers, copolymers of maleic anhydride and/or phtalic anhydride with styrene and some polymers derivated from cinnamic acid. The following compounds were used as sensitizers benzophenone, 4-chloro- and 4,4-dimethylbenzophenone [l, 3-6, 8, 9l, oC -and -derivatives of anthraquinone [3, 23] acetophenone, hydroquinone, triphenylmethane and pyridine li.] chlorobenzene and no less than trichlorinated n-paraffins [6], a complex of zink chloride with o-dia-nizidine fill potassium bichromate [l2j, anthracene fl3, 14] 2,5-methoxy-4-amino-trans-stilbene [l5], benzyl ideneacetophenone fl6-l8] -thiophenylacetophenone,... 

Simple vinyl polymers are named by attaching the prefix poly to the monomer name. For example, the polymer made from styrene becomes polystyrene. However, when the monomer name consists of more than one word or is preceded by a letter or a number, the monomer is enclosed in parenthesis with the prefix poly. Thus polymers derived from vinyl chloride or 4-chlorostyrene are designated polyfvinyl chloride) and poly(4-chlorostyrene), respectively. This helps to remove any possible ambiguity. 

Source-based names are, for example, the ones we are accustomed to seeing for polymers such as polyethylene (see Section 6.21) and polystyrene (see Section 11.17). When the name of the monomer is a single word, the polymer derived from it is generated by simply adding the prefix poly-. When the name of the monomer consists of two words, both words are enclosed in parentheses immediately following poly. Thus, polyacrylonitrile and poly(vinyl chloride) are the polymers of acrylonitrile and vinyl chloride, respectively. 

Cadmium ricinoleate n. [CH3(CH2)5-CHOHCH2CH=CH(CH2)7COO]2-Cd. A white powder derived from castor oil, used as a heat stabilizer for vinyl chloride polymers and copolymers. 

Binders, vehicles, or resins may be of several types. AUsyd resins are among the most common and are composed of polymers of alcohols and adds—thus the term alkyd -ale from alcohol, -yd standing for add). Acrylic resins are based on polymers of methacrylate and methyl methacrylate (esters. Figure 11.32) similarly, vinyl resins are derived from vinyl chloride. Urethanes (polyurethanes) and some silicon-based resins are also encountered. Watercol-or paints use gum arabic as a binder. This material is obtained from the sap of the acacia tree and, when dry, forms a dear, water-soluble polymer matrix. 

Polyvinyl Acetate n A colorless, odorless, nontoxic, transparent, thermoplastic, water-insoluble, resinous high polymer derived from the polymerization of vinyl acetate with a catalyst used as a latex binder in certain paints and as an intermediate in the synthesis of polyvinyl acetal and polyvinyl alcohol. The major use is in water-based latex paints, adhesives, fabric finishes, and lacquers. In the plastics industry, the copolymers of vinyl acetate, particularly with vinyl chloride, are of most interest. Abbreviation for PVA and PVAc. 

Other typical pyrotechnic fuels include charcoal, sulfur, boron, siUcon, and synthetic polymers such as poly(vinyl alcohol) and poly(vinyl chloride). Extensive use has been made of natural products such as starches and gums, and the use of these materials continues to be substantial in the fireworks industry. MiUtary pyrotechnics have moved away from the use of natural products due to the inherent variabiUty in these materials depending on climatic conditions during the growth of the plants from which the compounds are derived. 

Diesters. Many of the diester derivatives are commercially important. The diesters are important plasticizers, polymer intermediates, and synthetic lubricants. The diesters of azelaic and sebacic acids are useflil as monomeric plasticizing agents these perform weU at low temperatures and are less water-soluble and less volatile than are diesters of adipic acid. Azelate diesters, eg, di- -hexyl, di(2-ethylhexyl), and dibutyl, are useflil plasticizing agents for poly(vinyl chloride), synthetic mbbers, nitroceUulose, and other derivatized ceUuloses (104). The di-hexyl azelates and dibutyl sebacate are sanctioned by the U.S. Food and Dmg Administration for use in poly(vinyl chloride) films and in other plastics with direct contact to food. The di(2-ethylhexyl) and dibenzyl sebacates are also valuable plasticizers. Monomeric plasticizers have also been prepared from other diacids, notably dodecanedioic, brassyflc, and 8-eth5lhexadecanedioic (88), but these have not enjoyed the commercialization of the sebacic and azelaic diesters. 

For instance, poly(vinyl chloride), derived from the polymerisation of vinyl chloride (chloroethene), CH2=CHC1, contains repeating units -CH2-CHCI-. However, long-chain molecules are of various lengths and the units are not necessarily all uniquely oriented and joined in a regular fashion, which would result in the polymer formulated -(CH2-CHC1)h. ... 

Configuration also refers to structural regularity with respect to the substituted carbon within the polymer chain (Figure 1.9). For linear homopolymers derived from monomers of the form H2C = CHX, such as styrene and vinyl chloride, configuration from monomeric unit to monomeric unit can vary somewhat randomly (atactic abbreviated at) with respect to the geometry and configuration about the carbon to which the X is attached, or can vary alternately (syndiotactic st), or can be uniform (isotactic it) when all the X groups can be placed on the same side of a backbone plane. 

The photo-cross-linkability of a polymer depends not only on its chemical structure, but also on its molecular weight and the ordering of the polymer segments. Vinyl polymers, such as PE, PP, polystyrene, polyacrylates, and PVC, predominantly cross-link, whereas vinylidene polymers (polyisobutylene, poly-2-methylstyrene, polymethacrylates, and poly vinylidene chloride) tend to degrade. Likewise, polymers formed from diene monomers and linear condensation products, such as polyesters and polyamides, cross-link easily, whereas cellulose and cellulose derivatives degrade easily. ... 

For low radiation doses, peroxides accumulate almost linearly with dose. However, after a certain dose has been reached, their concentration tends to level off. This conclusion can be derived from the observed change in the rate of graft copolymerization initiated by polymers subjected to increasing doses of preirradiation in air. Figure 2 illustrates this effect in the case of grafting acrylonitrile onto polyethylene (2). The drop in the yield of peroxide production presumably results from the efficient radiation-induced decomposition of these peroxides. Peroxides are known to decompose under free radical attack, and selective destruction of peroxides under irradiation has been established experimentally (8). This decomposition can become autocatalytic, and sometimes the concentration of peroxides may reach a maximum at a certain dose and decrease on further irradiation. Such an effect was observed in the case of poly (vinyl chloride). Figure 3 shows the influence of preirradiation dose on the grafting ratio obtained with poly (vinyl chlo-... 

The most common molecules from which polymers are made are ethylene (chemical formula CH2=CH2) and its derivatives. The key to its polymerisation is the double bond, which opens to form bonds to other ethylenes and the end result is a chain of CH2 groups, -CH2-CH2-CH2-CH2-CH2- which can be millions of carbons long. This is polyethylene. Another common polymer is poly(vinyl chloride) which is made from vinyl chloride (chemical formula CH2=CHCl) and is better known as PVC. See also PPMA and HEMA. The following table lists various common polymers headed by those based on ethylene and its derivatives ... 

Most thermal stabilizers for poly (vinyl chloride) are metal salts of carboxylic acids or mercaptans. The commonly used metals are cadmium, barium, zinc, lead, calcium, and dibutyltin. Originally it was assumed the metal salts act as scavengers for hydrogen chloride. However, Frye and Horst (7, 8) found evidence for the introduction of ester groups in the polymer from metal carboxylate stabilizers, which led them to postulate that thermal stabilizers function by substituting the unstable chlorine atoms with the ligands of the stabilizer to yield derivatives which are more thermally stable than the original chloride. 

Several procedures exists for calculating the heats of polymerization for various monomers but they are not very important. It is still more useful to consider the experimentally measured values as the best basis both for theoretical studies and for practical calculations. For ethylene derivatives, the value of — AHlc (from liquid monomer to amorphous solid polymer) ranges from 33.5 kJ mol-1 for a-methylstyrene, through ca. 96 kJ mol-1 for vinyl chloride, to 174 kJ mol-1 for tetrafluoroethylene. 

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