Styrene plastics high-impact

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). 

In addition to polystyrene and high-impact polystyrene there are other important styrene-based plastics. Most important of these is ABS, with a global capacity of about 5 X 10 t.p.a. and production of about 3 X 10 t.p.a. The styrenic PPO materials reviewed in Chapter 21 have capaeity and production figures about one-tenth those for ABS. Data for the more specialised styrene-acrylonitrile copolymers are difficult to obtain but consumption estimates for Western Europe in the early 1990s were a little over 60000 t.p.a. 

Polystyrene (PS) The volume of expanded polystyrene produced probably exceeds the volume production of all other plastics (excluding the polyurethanes) put together. At least half the weight of polystyrene produced is in the form of high impact polystyrene (HIPS)—a complex blend containing styrene-butadiene rubber or polybutadiene. 

Styrene maleic anhydride SMA is a copolymer made with or without rubber modifiers. They are sometimes alloyed with ABS and offer good heat resistance, high impact strength and gloss but with little appreciable improvement in weatherability or chemical resistance over other styrene based plastics. 

In a block copolymer, a long segment made from one monomer is followed by a segment formed from the other monomer. One example is the block copolymer formed from styrene and butadiene. Pure polystyrene is a transparent, brittle material that is easily broken polybutadiene is a synthetic rubber that is very resilient, but soft and opaque. A block copolymer of the two monomers produces high-impact polystyrene, a material that is a durable, strong, yet transparent plastic. A different formulation of the two polymers produces styrene-butadiene rubber (SBR), which is used mainly for automobile tires and running shoes, but also in chewing gum. 

The principal use of acrylonitrile since the early 1950s has been in the manufacture of so-called acrylic textile fibers. Acrylonitrile is first polymerized to polyacrylonitrile, which is then spun into fiber. The main feature of acrylic fibers is their wool-like characteristic, making them desirable for socks, sweaters, and other types of apparel. However, as with all synthetic textile fibers, fashion dictates the market and acrylic fibers currently seem to be in disfavor, so this outlet for acrylonitrile may be stagnant or declining. The other big uses for acrylonitrile are in copolymers, mainly with styrene. Such copolymers are very useful for the molding of plastic articles with very high impact resistance. 

Transition from liquid behavior to solid behavior has been reported with fine particle suspensions with increased filler content in both Newtonian and non-Newtonian liquids. Industrially important classes are rubber-modified polymer melts (small rubber particles embedded in a polymer melt), e.g. ABS (acrylo-nitrile-butadiene-styrene) or HIPS (high-impact polystyrene) and fiber-reinforced polymers. Another interesting suspension is present in plasticized polyvinylchloride (PVC) at low temperatures, when suspended PVC particles are formed in the melt [96], The transition becomes evident in the following... 

Thermoplastics are predominant among the plastics used for the household, entertainment office appliance industry with styrenics pre-eminent, including polystyrene, high-impact polystyrene, EPS, ABS, SAN, ASA. .. followed by PP. Several engineering thermoplastics such as PA, PC, PBT, PPO and POM are also used. 

The concept is similar to the grafting of plants in botany. To form a styrene-butadiene graft polymer, already polymerized butadiene is dissolved in monomeric styrene and an initiator is added. Because polybutadiene readily undergoes chain transfer at the allylic sites, polystyrene chains grow on the polybutadiene backbone. This forms high impact polystyrene, a low cost plastic that is otherwise too brittle without the grafting. 

B.J. Jody, B. Arman, D.E. Karvelas, J.A. Pomykala, Jr., and E.J. Daniels, Method for the separation of high impact polystyrene (HIPS) and acrylonitrile butadiene styrene (ABS) plastics, US Patent 5 653867, assigned to The University of Chicago (Chicago, IL), August 5,1997. 

Acrylonitrile (CH2=CH-CN) was made from acetylene and HCN until the 1960s. Today it is made by direct ammoxidation of propylene. Its major use is in making polyacrylonitrile, which is mainly converted to fibers (Orion). It is also copolymerized with butadiene and styrene to produce high impact plastics. 

Characteristic functions and the representative structures of plastics additives providing marketable and durable materials are included in this chapter. Types of additives for plastics used in contact with food are listed in Table 3-1. Similar additives as for PS are used for elastomer-modified plastics forming multilayer systems (blends) and used rather exceptionally in contact with food, such as high-impact polystyrene (HIPS) or acrylonitrile-butadiene-styrene polymer (ABS). Some of the additives, stabilizers in particular, are very reactive and are present in the plastic matrix in a chemically transformed form. 

The following TPs are the main thermoforming materials processed high-impact and high-heat PS, HDPE, PP, PVC, ABS, CPET, PET, and PMMA. Other plastics of lesser usage are transparent styrene-butadiene block copolymers, acrylics, polycarbonates, cellulosics, thermoplastic elastomers (TPE), and ethylene-propylene thermoplastic vulcanizates. Coextruded structures of up to seven layers include barriers of EVAL, Saran, or nylon, with polyolefins, and/or styreneics for functional properties and decorative aesthetics at reasonable costs.239-241... 

To improve the properties of PLA, plasticizers, special additives such as chain-extenders, polymer blends, and composites are commonly investigated. Martin and Averous (10) have studied the effects of various plasticizers on the properties of PLA. Pilla et al. (11-12) have investigated the effects of chain-extenders on the foaming properties of PLA. In addition, a vast number of studies have been conducted to enhance the properties of PLA by blending it with various polymers such as polyethylene oxide (PEO), polypropylene oxide (PPO), polyvinyl acetate, polyolefins, polystyrene, HIPS (high impact polystyrene), polyacetals, polycarbonate, and acrylonitrile butadiene styrene (ABS) (13-26). 

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