Thermoplastics polystyrene

The decade 1930-1940 saw the initial industrial development of four of today s major thermoplastics polystyrene, poly(vinyl chloride) (PVC), the polyolefins and poly(methyl methacrylate). Since all these materials can be considered formally as derivatives of ethylene they have, in the past, been referred to as ethenoid plastics however, the somewhat inaccurate term vinyl plastics is now usually preferred. 

Novel styrenic-based TPEs based on blends of a thermoplastic (polystyrene or styrene acrylonitrile) with a rubber (styrene butadiene or ethylene vinylacetate), with special reference to compatibilization and dynamic vulcanization, were reported by Patel et al. The performance properties were correlated with the interaction parameter and the phase morphology of the blend components [62]. 

Stjwex. [Faro/Engineering Thermoplastics] Polystyrene, SAN, ABS, or PPO resins, some glass or carbon reinforced thermoidastics. 

Thermoplastic polystyrene spoon before (top) and after (bottom) stirring a hot cup of coffee. The deformation caused by heating can be reversed by repeating the heating process. 

The most important thermoplastic foams are based on thermoplastic polystyrene and on the polyolefins PE, PP and PVC. The foaming process generally involves expansion resulting from use of chemical or physical blowing agents (Table 6). 

The history of synthetic polymers is incredibly short. The term polymer was introduced in 1832. The first synthetic polymer (phenol-formaldehyde) was commercialized as Bakelite in 1909, while the first thermoplastic (polystyrene, Trolitul ), 6 years later. The early polymer industry was developed by entrepreneurs that had little if any technical background. The commercial successes (and... 

Early development concentrated on the improvement of standard plastics, such as the thermosets, phenolic and polyester resins, and the thermoplastics, polystyrene, PVC, and polyolefins. More recently there has been considerable development of impact modification systems for engineering thermoplastics. 

The development of the styrenic block copolymers has created special challenges for resin manufacturers. These block copolymers are of two basic types. The first are the triblock copolymers, consisting of an elastomeric midblock and thermoplastic polystyrene end-blocks. These can be either the linear triblock copolymers, such as the Kraton polymers from Shell Chemical Company or the Europrene polymers from Enichem, or radial block copolymers, initially produced by Phillips Petroleum and now available from Petrofine SA under the tradename Finaprene. The linear triblock copolymers are the most widely used in the adhesive industry. 

Casting resin Thermoplastic elastomer Cast resin, flexible Mineral- and/or glass-filled Epoxy molding and encapsulating compound Polystyrene... 

Gun Propellents. Low sensitivity gun propeUants, often referred to as LOVA (low vulnerabUity ammunition), use RDX or HMX as the principal energy components, and desensitizing binders such as ceUulose acetate butyrate or thermoplastic elastomers (TPE) including poly acetal—polyurethane block copolymers, polystyrene—polyacrjiate copolymers, and glycidyl azide polymers (GAP) to provide the required mechanical... 

Physical or chemical vapor-phase mechanisms may be reasonably hypothesized in cases where a phosphoms flame retardant is found to be effective in a noncharring polymer, and especially where the flame retardant or phosphoms-containing breakdown products are capable of being vaporized at the temperature of the pyrolyzing surface. In the engineering of thermoplastic Noryl (General Electric), which consists of a blend of a charrable poly(phenylene oxide) and a poorly charrable polystyrene, experimental evidence indicates that effective flame retardants such as triphenyl phosphate act in the vapor phase to suppress the flammabiUty of the polystyrene pyrolysis products (36). 

Triphenyl phosphate [115-86-6] C gH O P, is a colorless soHd, mp 48—49°C, usually produced in the form of flakes or shipped in heated vessels as a hquid. An early appHcation was as a flame retardant for cellulose acetate safety film. It is also used in cellulose nitrate, various coatings, triacetate film and sheet, and rigid urethane foam. It has been used as a flame-retardant additive for engineering thermoplastics such as polyphenylene oxide—high impact polystyrene and ABS—polycarbonate blends. 

Phase Separation. Microporous polymer systems consisting of essentially spherical, intercoimected voids, with a narrow range of pore and ceU-size distribution have been produced from a variety of thermoplastic resins by the phase-separation technique (127). If a polyolefin or polystyrene is insoluble in a solvent at low temperature but soluble at high temperatures, the solvent can be used to prepare a microporous polymer. When the solutions, containing 10—70% polymer, are cooled to ambient temperatures, the polymer separates as a second phase. The remaining nonsolvent can then be extracted from the solid material with common organic solvents. These microporous polymers may be useful in microfiltrations or as controlled-release carriers for a variety of chemicals. 

Thermoplastics. The highest consumption of color concentrates is in thermoplastic resins, such as low and high density polyethylene, polypropylene, PVC, and polystyrene. Processing techniques for thermoplastics are usually based on dry color dispersion in a compatible resin (36). 

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... 

Noryl. Noryl engineering thermoplastics are polymer blends formed by melt-blending DMPPO and HIPS or other polymers such as nylon with proprietary stabilizers, flame retardants, impact modifiers, and other additives (69). Because the mbber characteristics that are required for optimum performance in DMPPO—polystyrene blends are not the same as for polystyrene alone, most of the HIPS that is used in DMPPO blends is designed specifically for this use (70). Noryl is produced as sheet and for vacuum forming, but by far the greatest use is in pellets for injection mol ding. 

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). 

General-Purpose Polystyrene. Polystyrene is a high molecular weight M = 2 — 3 x 10 ), crystal-clear thermoplastic that is hard, rigid, and free of odor and taste. Its ease of heat fabrication, thermal stabiUty, low specific gravity, and low cost result in mol dings, extmsions, and films of very low unit cost. In addition, PS materials have excellent thermal and electrical properties that make them useful as low cost insulating materials (see Insulation, ELECTRIC Insulation, thermal). 

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). 

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