Acrylonitrile-butadiene-styrene part production

MABS polymers (methyl methacrylate-acrylonitrile-butadiene-styrene) together with blends composed of polyphenylene ether and impact-resistant polystyrene (PPE/PS-I) also form part of the styrenic copolymer product range. Figure 2.1 provides an overview of the different classes of products and trade names. A characteristic property is their amorphous nature, i.e. high dimensional stability and largely constant mechanical properties to just below the glass transition temperature, Tg. 

Styrene is frequently used as part of some terpolymers with large practical utilization. One such copolymer is acrylonitrile-butadiene-styrene terpolymer (ABS). Usually it is made as poly(l-butenylene-graft-l-phenylethylene-co-cyanoethylene). This form of the copolymer can be made by grafting styrene and acrylonitrile directly on to the polybutadiene latex in a batch or continuous emulsion polymerization process. Grafting is achieved by the free-radical copolymerization of styrene and acrylonitrile monomers in the presence of polybutadiene. The degree of grafting is a function of the 1,2-vinyl content of the polybutadiene, monomer concentration, extent of conversion, temperature and mercaptan concentration (used for crosslinking). The emulsion polymerization process involves two steps production of a rubber latex and subsequent polymerization of styrene and acrylonitrile in the presence of the rubber latex to produce an ABS latex. 

As a measure of the level of sophistication of the industry the types of polymers consumed was as shown in figure 2. Others are mainly engineering thermoplastics (ETP), such as nylon, polyacrylates, polyacetals, polycarbonates, polyesters, and polpropylene oxide etc... These ETP s are growing at rates up to 20%. The main uses for plastic products are computer and business machine parts as well as design engineered products. The consumption of styrenic plastics (polystyrene acrylonitrile butadiene styrene - ABS) is high, relative to polyolefins, because of their demand in electric/electronic end-uses. 

A substantial part of the synthetic polymer dispersions is commercialized as dry products. These include styrene-butadiene rubber (SBR) for tires, nitrile rubbers, about 10% of the total poly(vinyl chloride) production, 75% of the total acrylonitrile-butadiene-styrene... 

BTBPE is used as an additive flame retardant, replacing octaPBDE, for polystyrene and acrylonitrile-butadiene-styrene products. BTBPE was found in the eggs of birds and especially in the dust and air in plants for the liquidation of electronic waste. Animal studies indicate minimum BTBPE absorption in the digestive tract. The major part of BTBPE is probably excreted, partly as metabolites, such as hydroxylated BTBPE and 2,4,6-tribromophenol. 

The use of a soluble metal-chelating agent such as tetrasodium ethylenediamine tetraacetate effectively stabilizes an anaerobic formulation against small amounts of metal contamination [173]. The wide variety of appUcations of anaerobic adhesives and sealants is made possible by the modifications which make the viscosity appropriate to the application. An application which requires penetration into close fitting parts should have very low viscosity while a product used with large, loose fitting parts should have a high viscosity. Polymethacrylates, cellulose esters, butadiene-styrene copolymers, acrylonitrile-butadiene-styrene copolymers, polyfvinyl chloride), copolymers of vinyl chloride and vinyl acetate, polyfvinyl acetate), cellulose ethers, polyesters, polyurethanes, and other thermoplastic resins have been used to control the flow characteristics of anaerobic sealants [174]. 

ABS. A thermoplastic, a terpolymer of acrylonitrile, butadiene, and styrene. ABS products are characterized by toughness and rigidity as well as by a higher thermal stability and scratch resistance than those of many other thermoplastics. Glass fibre reinforced, fiame-retardant, and other modified ABS grades are also available. ABS components can be metallized, for example, chromium-plated. Some applications panels and other car accessories casing and various parts of business machines, appliances, radio, TV sets, tape recorders pipes. Trade names Cycolac (USA), Kralastic (USA), Novodur (FRG), Techster (F), Terluran (FRG). 

When chlorinated polyether is used instead of butadiene, a copolymer called acrylonitrile-chlorinated polyethylene styrene (ACS) is produced. This copolymer has improved flame resistance and weatherability. [See also acrylonitrile-chlorinated styrene (ACS) teropolymer polyethylene styrene (ACS) terpolymer.] Acrylic styrene acrylonitrile (ASA) is produced by grafting an acrylic ester elastomer onto the styreneacrylonitrile segment. This results in better outdoor weathering. ASA is used in products such as gutters, mailboxes, shutters, and outdoor furniture. (See also acrylic styrene acrylonitrile.) Modifications are also available that enhance adhesion of electroplated coating to the ABS plastic. ABS is the most widely used material for electroplated plastic parts. 

Rubbers and elastomeric products for practical applications are usually blends of different elastomer types that develop specific domain morphologies at the microscale, and, therefore, they are a part of this chapter. The most common representatives of the ruhher family are natural ruhher (NR) and the synthetic polyhutadiene ruhher (PB). There are various copolymers of butadiene with styrene (styrene butadiene rubber, SBR) or acrylonitrile (acrylonitrile-butadiene rubber, NBR). Several elastomers have been developed for special purposes, such as EVA (ethylene vinyl acetate copolymer), PU (polyurethane), EPDM (ethylene propylene terpolymer), and siUcone rubber. 

The common feature of these materials was that all contained a high proportion of acrylonitrile or methacrylonitrile. The Vistron product, Barex 210, for example was said to be produced by radical graft copolymerisation of 73-77 parts acrylonitrile and 23-27 parts by weight of methyl acrylate in the presence of a 8-10 parts of a butadiene-acrylonitrile rubber (Nitrile rubber). The Du Pont product NR-16 was prepared by graft polymerisation of styrene and acrylonitrile in the presence of styrene-butadiene copolymer. The Monsanto polymer Lopac was a copolymer of 28-34 parts styrene and 66-72 parts of a second monomer variously reported as acrylonitrile and methacrylonitrile. This polymer contained no rubbery component. 

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