Styrenic plastics Polymer

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... 

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. 

Like almost all synthetic polymers, styrene plastics ate susceptible to degradation by heat, oxidation, uv radiation, high energy radiation, and shear, although... 

Many mbber-modified styrene plastics are fabricated into sheet by extmsion primarily for subsequent thermoforming operations. Much consideration has been given to the problem of achieving good surface quaUty in extmded sheet (230,231). Excellent surface gloss and sheet uniformity can be obtained with styrene-based polymers. 

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). 

As of 1992, the first specialty platable plastic, acrylonitrile—butadiene—styrene (ABS) terpolymer (see Acrylonitrile polymers, ABS resins), is used ia over 90% of POP appHcatioas. Other platable plastics iaclude poly(pheayleae ether) (see PoLYETPiERs), ayloa (see Polyamides), polysulfoae (see Polymers CONTAINING sulfur), polypropyleae, polycarboaate, pheaoHcs (see Pphenolic resins), polycarboaate—ABS alloys, polyesters (qv), foamed polystyreae (see Styrene plastics), and other foamed plastics (qv). 

Chemical reduction is used extensively nowadays for the deposition of nickel or copper as the first stage in the electroplating of plastics. The most widely used plastic as a basis for electroplating is acrylonitrile-butadiene-styrene co-polymer (ABS). Immersion of the plastic in a chromic acid-sulphuric acid mixture causes the butadiene particles to be attacked and oxidised, whilst making the material hydrophilic at the same time. The activation process which follows is necessary to enable the subsequent electroless nickel or copper to be deposited, since this will only take place in the presence of certain catalytic metals (especially silver and palladium), which are adsorbed on to the surface of the plastic. The adsorbed metallic film is produced by a prior immersion in a stannous chloride solution, which reduces the palladium or silver ions to the metallic state. The solutions mostly employed are acid palladium chloride or ammoniacal silver nitrate. The etched plastic can also be immersed first in acidified palladium chloride and then in an alkylamine borane, which likewise form metallic palladium catalytic nuclei. Colloidal copper catalysts are of some interest, as they are cheaper and are also claimed to promote better coverage of electroless copper. 

There are three principal families of styrene containing polymers, which are used to make commercial plastic products. The first family is pure polystyrene, the second family comprises random copolymers, and the final family consists of polystyrene chains grafted to blocks of rubbery polymers. There are also synthetic rubbers that contain significant concentrations of styrene, but these are outside the scope of this book. 

Styrene is a commercially important monomer that is used extensively in the manufacture of polystyrene resins and in co-polymers with acrylonitrile and 1,3-butadiene (reinforced plastics). Exposure to styrene occurs due to intake of food that has been in contact with styrene-containing polymers. lARC has determined that styrene is possibly carcinogenic to humans. There is no restriction on using styrene within the European Union (i.e., there is no SML). 

Methacrylonitrile (1) differs from 2 only in that it has a methyl (CH3) group on the a-carbon atom. It too is widely used in the preparation of homopolymers and copolymers, elastomers, and plastics and as a chemical intermediate in the preparation of acids, amides, amines, esters, and other nitriles. In a study conducted by the NTP in which 1 was administered orally to mice for 2 years, there was no evidence that it caused cancer, although other less serious toxic effects were noted [27]. Because 1 does not cause cancer, but undergoes many of the same nucleophilic addition reactions as 2 at the (3-carbon, it is sometimes used as a safer commercial replacement for 2, such as in the manufacture of an acrylonitrile-butadiene-styrene-like polymer that provides improved barrier properties to gases such as carbon dioxide in carbonated beverage containers. 

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)... 

Polymeric implants - [FOAMED PLASTICS] (Vol 11) - [ACRYLONITRTLEPOLYMERS - SURVEY AND SAN (STYRENE-ACRYLONITRILECO-POLYMERS)] (Vol 1) -for contraception [CONTRACEPTIVES] (Vol 7)... 

This study was therefore undertaken to prepare and evaluate acrylonitrile—butadiene-styrene (ABS) and methyl methacrylate-butadiene-styrene (MBS) polymers under similar conditions to determine whether replacement of acrylonitrile by methyl methacrylate could improve color stability during ultraviolet light aging, without detracting seriously from the good mechanical and thermal-mechanical properties of conventional ABS plastics. For purposes of control, the study also included briefer evaluation of commercial ABS, MBS, and acrylonitrile-butyl acrylate-styrene plastics. 

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. 

Hindered phenols are used preferentially for processing and long-term heat aging of PO where their very low-discoloring properties are advantageous (Pospisil, 1998 Zweifel, 1998 Pospisil, 1993). Phenolic antioxidants are effective also for thermal stabilization of styrene-based polymers. Low amounts are used in PET and aliphatic PA. Common concentrations in plastics range between 0.025 and 0.3 %. 

Arandes et al. [84] studied the catalytic degradation of several plastics (polypropylene, polystyrene, polystyrene-polybutadiene) dissolved in a light cycle oil (ECO) in a riser simulator of a ECC unit using both a fresh and an equilibrated ECC catalysts. Similarly, De la Puente [85, 112] studied the catalytic degradation of styrene-based polymers dissolved in benzene streams in the same riser simulator. Although the reported results are promising, oil refiners are reluctant regarding the inherent risks for the normal operation of the refinery units. 

Styrene [100-42-5] (phenylethene, vinjibenzene, phenjiethjiene, styrol, cinnamene), CgHc,CH=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 crystaUine polystyrene, mbber-modified impact polystyrene, expandable polystyrene, acrylonitrile—butadiene—styrene copolymer (ABS), styrene—acrjionitrile resins (SAN), styrene—butadiene latex, styrene—butadiene rubber (qv) (SBR), and unsaturated polyester resins (see AcRYLONiTRim polymers Styrene plastics). 

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