Styrenic plastics polystyrene

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. 

Eoamed polystyrene sheet has exceUent strength, thermal resistance, formabUity, and shock resistance, as weU as low density. It is widely known for its use in beverage cups, food containers, building insulation panels, and shock absorbent packaging. Polystyrene products can be recycled if suitable coUection methods are estabUshed. Eoamed polystyrene sheet can also be easily therm oformed (see Styrene plastics). 

Benzene, toluene, and xylene are made mosdy from catalytic reforming of naphthas with units similar to those already discussed. As a gross mixture, these aromatics are the backbone of gasoline blending for high octane numbers. However, there are many chemicals derived from these same aromatics thus many aromatic petrochemicals have their beginning by selective extraction from naphtha or gas—oil reformate. Benzene and cyclohexane are responsible for products such as nylon and polyester fibers, polystyrene, epoxy resins (qv), phenolic resins (qv), and polyurethanes (see Fibers Styrene plastics Urethane POLYiffiRs). 

Over 70% of the total volume of thermoplastics is accounted for by the commodity resins polyethylene, polypropylene, polystyrene, and poly(vinyl chloride) (PVC) (1) (see Olefin polymers Styrene plastics Vinyl polymers). They are made in a variety of grades and because of their low cost are the first choice for a variety of appHcations. Next in performance and in cost are acryhcs, ceUulosics, and acrylonitrile—butadiene—styrene (ABS) terpolymers (see... 

In the eady 1920s, experimentation with urea—formaldehyde resins [9011-05-6] in Germany (4) and Austria (5,6) led to the discovery that these resins might be cast into beautiful clear transparent sheets, and it was proposed that this new synthetic material might serve as an organic glass (5,6). In fact, an experimental product called PoUopas was introduced, but lack of sufficient water resistance prevented commercialization. Melamine—formaldehyde resin [9003-08-1] does have better water resistance but the market for synthetic glass was taken over by new thermoplastic materials such as polystyrene and poly(methyl methacrylate) (see Methacrylic polya rs Styrene plastics). 

Styrene [100-42-5] (phenylethene, viaylben2ene, phenylethylene, styrol, cinnamene), CgH5CH=CH2, is the simplest and by far the most important member of a series of aromatic monomers. Also known commercially as styrene monomer (SM), styrene is produced in large quantities for polymerization. It is a versatile monomer extensively used for the manufacture of plastics, including crystalline polystyrene, mbber-modifted impact polystyrene, expandable polystyrene, acrylonitrile—butadiene—styrene copolymer (ABS), styrene—acrylonitrile resins (SAN), styrene—butadiene latex, styrene—butadiene mbber (qv) (SBR), and unsaturated polyester resins (see Acrylonithile polya rs Styrene plastics). 

Polystyrene [9003-53-6] (PS), the parent of the styrene plastics family, is a high molecular weight linear polymer which, for commercial uses, consists of - 1000 styrene units. Its chemical formula (1), where n = - 1000, tells htde of its properties. 

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). 

Self-Test F.5A The molar mass of styrene, which is used in the manufacture of the plastic polystyrene, is 104 g-mol", and its empirical formula is CH. Deduce its molecular formula. 

Polystyrene (PS), 7 610t 23 326, 348, 358. See also Polystyrenes Styrene Styrene plastics biodegradation of, 23 376 brominated, 11 470-474 chain transfer to, 23 383 colloidal suspensions, 7 275 crystalline syndiotactic, 23 388 decomposition of, 14 109 effect of orientation on oxygen permeability, 3 393t... 

ISO 1622-1 1994 Plastics - Polystyrene (PS) moulding and extrusion materials - Part 1 Designation system and basis for specifications ISO 1622-2 1995 Plastics - Polystyrene (PS) moulding and extrusion materials - Part 2 Preparation of test specimens and determination of properties ISO 2561 1974 Plastics - Determination of residual styrene monomer in polystyrene by gas chromatography... 

Copolymerization allows the synthesis of an almost unlimited number of different products by variations in the nature and relative amounts of the two monomer units in the copolymer product. A prime example of the versatility of the copolymerization process is the case of polystyrene. More than 11 billion pounds per year of polystyrene products are produced annually in the United States. Only about one-third of the total is styrene homopolymer. Polystyrene is a brittle plastic with low impact strength and low solvent resistance (Sec. 3-14b). Copolymerization as well as blending greatly increase the usefulness of polystyrene. Styrene copolymers and blends of copolymers are useful not only as plastics but also as elastomers. Thus copolymerization of styrene with acrylonitrile leads to increased impact and solvent resistance, while copolymerization with 1,3-butadiene leads to elastomeric properties. Combinations of styrene, acrylonitrile, and 1,3-butadiene improve all three properties simultaneously. This and other technological applications of copolymerization are discussed further in Sec. 6-8. 

Film -use of microbial polysaccharides [MICROBIAL POLYSACCHARIDES] (Vol 16) -cellulose esters m [CELLULOSE ESTERS - ORGANIC ESTERS] (Vol 5) -drying of [DRYING] (Vol 8) -by extrusion [PLASTIC PROCESSING] (Vol 19) -ITOPE [OLEFIN POLYMERS - POLYETHYLENE - HIGH DENSITY POLYETHYLENE] (Vol 17) -from LDPE [OLEFIN POLYMERS - POLYETHYLENE - LOW DENSITY POLYETHYLENE] (Vol 17) -of LLDPE [OLEFIN POLYMERS - POLYETHYLENE - LINEAR LOW DENSITY POLYETHYLENE] (Vol 17) -of polyethylene oxide) [POLYETHERS - ETHYLENE OXIDE POLYMERS] (Vol 19) -of polystyrene [STYRENE PLASTICS] (Vol 22) -m printing processes [PRINTING PROCESSES] (Vol 20)... 

As of 1992, the first specialty platable plastic, acrylonitrile—butadiene—styrene (ABS) terpolymer (see Acrylonitrile polymers, abs resins), is used in over 90% of POP applications. Other platable plastics include poly(phenylene ether) (see Polyethers), nylon (see Polyamides), polysulfone (see Polymers containing sulfur), polypropylene, polycarbonate, phenolics (see Pphenolic resins), polycarbonate—ABS alloys, polyesters (qv), foamed polystyrene (see Styrene plastics), and other foamed plastics (qv). 

Unlike bulk plastics and paper where unwanted substances can be removed by vacuum stripping (e.g. vinylchloride monomer from polyvinylchloride, styrene from polystyrene) or by washing (e.g. organic and metallic residues in mass-polymerised plastics), adhesives by their gummy nature are difficult to clean-up. Residues of incomplete polymerisation and reaction by-products could be effectively retained and may subsequently migrate. On the other hand, adhesives are generally not used in direct contact with the packaged foods. Rather, they are applied at seams and pack ends and any contact with the food is likely to be incidental and limited in area. 

PBBs were also widely used as flame retardant additives in polymer formulations, e.g., synthetic fibers, molded plastics and plastic housings also in the manufacture of polycarbonates, polyesters, polyolefins and polystyrenes. Nixed ABS polymers (acrylonitrile -butadiene - styrene), plastics, coatings and lacquers also contained added PBBs to enhance fire-retardancy. 

FIGURE 2.23 Scheme for fabrication of plastic microdevices from silicon master using an intermediate soft mold, (a) Silicon structures are fabricated using conventional photolithography and reactive ion etching, (b) PDMS is cured in situ over the silicon master, (c) Polystyrene is hot embossed onto the PDMS mold or polymerized in situ from partially polymerized styrene, (d) Polystyrene replica is separated from the mold [85]. Reprinted with permission from Springer Science and Business Media. 

Major applications for styrene plastics are summarized in Table III (23). The packaging and serviceware (disposables) markets predominate, and account for approximately 50% of the total. One of the most rapidly growing portions of these markets is in low-density (usually 1-10 Ib/ft ) polystyrene foams, either in the form of extruded foam sheet or expanded polystyrene beads (EPS). Projections indicate that production of these foams will be greater than 2000 metric tons (24). 

The use of cellular styrene plastics for insulation has been widespread for many years (25). More recently, polystyrene "structural" foams have been used, especially in wood replacement applications. Such use is expected to grow in the future, particularly as wood becomes less available and greater demands are placed on more efficient use of "short" plastic materials. 

Additional opportunities in the styrene plastics industry exist for the development of products having such unique properties as high heat resistance and optical transparency. Arco produces the Dylark family of heat-resistant styrene plastics, which are copolymers of styrene-maleic anhydride. These products have a good balance of mechanical properties and have a heat distortion (under ASTM D68) of 234 F (33) which is markedly higher than homo polystyrene. 

Perhaps the best known member of the "heat-resistant" styrene plastics family is General Electric s Noryl (34). Noryl is an alloy of poly(phenylene oxide) and high-impact polystyrene. Heat deflection temperatures for Noryl range as high as 300 °F. The balance of mechanical properties is excellent, although processability is more difficult than for conventional styrene plastics. 

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