HIGH IMPACT

At the time the experiments were perfomied (1984), this discrepancy between theory and experiment was attributed to quantum mechanical resonances drat led to enhanced reaction probability in the FlF(u = 3) chaimel for high impact parameter collisions. Flowever, since 1984, several new potential energy surfaces using a combination of ab initio calculations and empirical corrections were developed in which the bend potential near the barrier was found to be very flat or even non-collinear [49, M], in contrast to the Muckennan V surface. In 1988, Sato [ ] showed that classical trajectory calculations on a surface with a bent transition-state geometry produced angular distributions in which the FIF(u = 3) product was peaked at 0 = 0°, while the FIF(u = 2) product was predominantly scattered into the backward hemisphere (0 > 90°), thereby qualitatively reproducing the most important features in figure A3.7.5. 

However, the situation is much less complex for NMR spectra. Whereas measurement conditions may have a high impact on NMR spectra, chemical shift... 

Molding and glass-fiber- High-impact fiber- disulfide- nylon 6... 

Properties Heat- resistant Extrusion Heat- resistant High-impact Elame- retarded Platable 20% glass-reinforced... 

Properties resistant Extrusion resistant High-impact retarded Platable reinforced... 

Styrene-acrylonitrile copolymer Styrene- butadiene copolymer, high-impact Polysulfone ... 

Properties Unfilled reinforced high-impact Unfilled reinforced sulfone) sulfone)... 

Laboratory tests indicated that gamma radiation treatment and cross-linking using triaHylcyanurate or acetylene produced a flexible recycled plastic from mixtures of polyethylene, polypropylene, general-purpose polystyrene, and high impact grade PS (62). 

Properties ASTM Method High impact Medium impact Heat resistant... 

Acrylonitrile—Butadiene—Styrene. Available only as sheet, ABS has good toughness and high impact resistance. It is readily therm oform able over a wide range of temperatures and can be deeply drawn. ABS has poor solvent resistance and low continuous-use temperature. It is often used in housings for office equipment (see Acrylonitrile polymers). 

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. 

Property AST M test ABS Noryl a Nylon b P< Polyeste d r HD PE Polypropyle ne High impact polystyrene Polyurethane PV C... 

Structural Components. In most appHcations stmctural foam parts are used as direct replacements for wood, metals, or soHd plastics and find wide acceptance in appHances, automobUes, furniture, materials-handling equipment, and in constmction. Use in the huil ding and constmction industry account for more than one-half of the total volume of stmctural foam appHcations. High impact polystyrene is the most widely used stmctural foam, foUowed by polypropylene, high density polyethylene, and poly(vinyl chloride). The constmction industry offers the greatest growth potential for ceUular plastics. 

Glass-Based Grades. Grade G-3 is glass fabric with phenohc resin binder which shows high impact and flexural strength. It is used for thermal and mechanical apphcations and has good dimensional stabihty. 

The oxidative coupling of 2,6-dimethylphenol to yield poly(phenylene oxide) represents 90—95% of the consumption of 2,6-dimethylphenol (68). The oxidation with air is catalyzed by a copper—amine complex. The poly(phenylene oxide) derived from 2,6-dimethylphenol is blended with other polymers, primarily high impact polystyrene, and the resulting alloy is widely used in housings for business machines, electronic equipment and in the manufacture of automobiles (see Polyethers, aromatic). A minor use of 2,6-dimethylphenol involves its oxidative coupling to... 

Besides appHcation as heat-resistant molding powders for electronic and other appHcations, DAIP copolymers have been proposed for optical apphcations. Lenses of high impact resistance contain 50% DAIP, 20% benzyl methacrylate, and larger amounts of CR-39 (59). A lens of refractive index 71- = 1.569 andlow dispersion can be cast from phenyl methacrylate, DAIP, and isopropyl peroxide (60). Lenses of better impact properties can be obtained by modifying DAIP with aHyl benzoate (61). 

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