Polypropylenes, plastics

The major uses of ethylene and propene are as starting materials for the preparation of polyethyl ene and polypropylene plastics fibers and films These and other applications will be described in Chapter 6... 

Polypropylene Plastic or resin derived from the polymerization of... 

Efforts to improve IUDs have led to the use of medicated devices. Two types of agents are generally used—contraceptive metals and steroid hormones. The metal device is exemplified by the CU-7, a polypropylene plastic device in the shape of the number 7. Copper is released by a combination of ionization and chelation from a copper wire wrapped around the vertical limb. This system is effective for up to 40 months. 

Figure 2-9 (a) Class A glass volumetric flask. [Courtesy A. H. Thomas Co., Philadelphia, PA.] (fc>) Class B polypropylene plastic volumetric flask for trace analysis. [Courtesy Fisher Scientific, Pittsburgh, PA.] Class A flasks meet tolerances of Table 2-3. Class B tolerances are twice as big as Class A tolerances, (c) Short-form volumetric flask with Teflon-lined screw cap fits in the analytical balance in Figure 2-3a. Teflon protects the cap from chemical attack. 

PROBLEM 12.8 At high temperatures, cyclopropane is converted to propene, the material from which polypropylene plastics are made ... 

Margarine, cakes, chocolate, salad oils, and other everyday edible products are produced from natural oils via catalytic hydrogenation. Polyethylene and polypropylene plastics, com-... 

Reinforced thermoset (RTS) plastic B-stage sheet material can be processed with its required heating cycle. However the most popular is to use reinforced thermoplastic (RTP) sheets usually using polypropylene plastics. Compared to injection molding RTPs, these stamped products can provide improved mechanical and physical properties with its longer fibers such as impact strength, heat distortion temperature, and much less anisotropy. 

Apparatus and techniques for the sampling and concentration of particulate and dissolved trace metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) from seawater were used to monitor ambient trace metal concentrations and heavy metal dis charges. Particulate trace metals were collected in 0.4 fim Nuclepore filter bags, and dissolved metals were concentrated on Chelex-100 chelating resin. The apparatus is constructed of polyethylene and polypropylene plastics to reduce possible sample contamination. 

Vexar [Du Pont], TM for both low and high-density polyethylene and polypropylene plastic netting. Available in a wide variety of forms and... 

As of 1998, Exxon was the third largest U.S. corporation in terms of revenues, in excess of 122 billion. It was incorporated in the state of New Jersey in 1898 and became a distinct entity upon the dissolution of the Standard Oil Trust in 1911. In 1997 about 14 billion (10.3% of Exxon s total revenue) was attributed to chemicals, making it the third largest U.S. producer of chemicals. The chemical products include basic petrochemicals, including olefins and aromatics, additives for fuels and lubricants, polyethylene and polypropylene plastics, specialty resins, specialty and commodity solvents, and performance chemicals for oil field operations. 

L., Goetz, M. A, Liesch, J. M., Zink, D. L., and Kaczorowski, G. J. (1993) A light stabilizer (Tinuvin 770) that elutes from polypropylene plastic tubes is a potent L-type Ca -channel blocker. Proc Natl. Acad. Sci USA 90,9523-9527. 

Propylene is obtained from refining of gasoline and thermal or catalytic cracking of hydrocarbons. It is used to produce polypropylene (plastic) and in the manufactnre of acetone, isopropanol, cumene, and propylene oxide. 

Hardness is another property which can be roughly tested with a fingemail applied to the underside of an ol ect. Plastics which can be marked with a fin-gemail include polyethylene, polypropylene, plasticized PVC and polyurethane while other types are not affected. A rather unusual test is to tap the plastic firmly with a fmgemail. If the sound is metallic, the plastic is likely to contain polystyrene. 

Brinell hardness See test, Brinell hardness. Brintzinger A chemist from Konstanz University, Hamburg, Germany, who m 1982 was the first to report on rnetalloorganic (metallocene) complex compounds of titanium and zirconium. Science and industry soon used his discovery to develop new polymerized compounds such as polyethylene and polypropylene plastics. Unlike its classical predecessors, the structure of metallocenes can be analyzed in all types of details, enabling it to be adapted to suit the requirements of the plastic researchers with a broad scope of possible variations. See catalyst, metallocene. 

Nonwoven melt-blown These fibers are composed of discontinuous filaments and are smaller than those of spun-bonded fabrics. Fibers produced are very fine with a typical diameter of 3 pm. Most commercial products are made of polyester or high melt-flow polypropylene plastic. 

Plastic lumber is recycled plastics processed such as commingled plastic, polyethylene plastic, and polypropylene plastic. To improve their performances different developments have been used such as specialty additives (lubricants, deoxidizers, etc.). An example is by adding as low as 10 wt% of short glass fiber to these recycled plastics can double their strength. Other fibers used include hemp, flax, and sisal. They are principally extruded other processes are used such as injection and compression molding, to produce products competitive to wood lumber on land and in the water. Compression molding allows for a deep-molded grain and a much more dense board. The density also helps the product resist moisture absorption and improves weatherability. 

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