Polystyrene crystal clear

Polystyrene (crystal) Clear-melt zinc stearate (bis-stearamides are usually adequate) secondaiy bis-amides assist How... 

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). 

Although it is called crystal clear polystyrene, atactic PS is amorphous and clear, as are PMMA and polycarbonate (PC). In contrast, hdpe and nylon 66 are highly crystalline and opaque. The relationship of packing efficiency to specific gravity and crystallinity is readily illustrated by ldpe and HDPE, which are 60 and 95% crystalline, respectively, and have specific gravities of 0.91 and 0.97, respectively. 

Polystyrene, the familiar crystal-clear brittle plastic used to make disposable drinking glasses and, when foamed, the lightweight white cups for hot drinks, is usually made by free-radical polymerization. Commercially an initiator is not used because polymerization begins spontaneously at elevated temperatures. At lower temperatures a variety of initiators could be used (e.g., 2,2 -azobis-(2-methylpropionitrile) which was used in the free-... 

Radiation-curing adhesives for crystal clear plastics such as acrylic glass/ Plexiglas, polystyrene, polycarbonate. 

For bonded joints with crystal clear plastics like polystyrene and acrylic glass to metals, it is also possible to apply radiation-curing adhesives (Sections 4.3.2 and 9.3.3). 

Polystyrene is generated from the monomer styrene by polymerisation in the presence of a catalyst. It is a crystal-clear plastic, easy to colour and completely free of odour and... 

The characteristic feature of polystyrene is its hardness. PS tends to stress cracking. The PS produced by free radical polymerization is atactic and therefore amorphous and crystal clear. The properties of PS are manifold altered by copolymerization and blending (see Table 2.2.5). 

Dry mineral powders must be fed using some type of bulk handling system, preferably totally enclosed to prevent contamination of non-filled parts. If a molder, for example, is making filled parts and also polystyrene chandelier lights, one or two specks of filler are enough to ruin the crystal-clear parts. 

Polystyrene and its copolymers account for about 10 percent of the domestic resin market. In its unmodified state, polystyrene is a hard, crystal-clear thermoplastic with relatively poor impact strength. Styrene is one of only a few vinyl monomers that can be polymerized by free radical, cationic, anionic, and Ziegler-Natta processes. 

Comments Crystal clear grades of general purpose polystyrene. ... 

Transparent Polymers. Amorphous thermoplastics, like poly (methyl methacrylate), polystyrene, SAN, PVC, or the cellulose esters are transparent and used for glazing, photographic film, blown bottles, or clear packaging containers. Only a few crystalline thermoplastics, like poly (4-methyl-l-pentane), where the crystalline and the amorphous phases have almost identical refractive indexes, or polycarbonate, which has smaller crystals than the wavelength of light, are also transparent. R. Kosfeld and co-workers analyzed the mobility of methyl groups in polycarbonate, poly (methyl methacrylate) and poly( -methyl styrene) by NMR spectroscopy. 

Example I A typical example is the history of the disposable seven-ounce drinking cup, made from readily available and low-cost clear, crystal polystyrene (PS). From an original model of such a cup at 15 g per unit, the side walls, the rim, and the bottom were gradually reduced, while adding thin ribs not only for strength but to make it moldable at all with such a narrow thickness. This resulted in cups of about 9 to 11 g, which was better than before but still not good enough. 

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