Polypropylene , atactic

The rhodium-catalyzed borylation of alkanes is applied to regiospecific functionalization of polyolefines.165,165a The reaction of polypropylenes (atactic, isotactic, and syndiotactic) with B2pin2 in the presence of Cp Rh( 74-C6Me6) catalyst at 200 °G affords the borylated polymers, which are treated with basic hydrogen peroxide in a mixture of THF and H20 to oxidize the boronate esters to the corresponding alcohols (Scheme 20). The hydroxylated polymers contain 0.2-1.5% hydroxymethyl side-chains. 

Isotactic polypropylene Atactic polystyrene Low density polyethylene High density polyethylene A soft polyurethane Nylon 6... 

According to Eqs. (2.1.68), the function 5o(q) displays a small, sharp peak at q = 0, otherwise being nearly stationary. Calculations performed on isotactic polypropylene, atactic polystyrene, and polyethylene with realistic parameters [27] lead to o(0) of 1.30,1.20, and 1.05, respectively. This square expansion ratio increases with the thickness, or degree of bulkiness, of the chain and decreases with the length of the statistical segment if the two quantities are taken as proportional to v A r and to C(0)/, respectively. 

The origin of plastic has more influence on the distribution of products of biomass / plastic co-pyrolysis. According to Table 3 the yield of light liquids from beech-wood / plastic mixtures (1 2 weight ratio) was decreased in the following sequence isotactic-polypropylene > atactic-polypropylene > polyethylene, whilst the yield of heavy liquids was increased in the same order,... 

Resconi, L. Silvestri, R. Polypropylene, Atactic (High Molecular Weight). In The Polymeric Materials Encyclopedia Salamone, J. C., Ed. CRC Press Boca Raton, 1996 p 6609. 

MAJOR APPLICATIONS The polymers referred to in this chapter include those families of homopolymers of propylene which are known to have elastomeric recovery properties at reasonable molecular weight and for which properties have been attributed to a crystallizable-noncrystallizable (e.g., isotactic-atactic) stereoblock structure, or to a major component with a stereoblock structure, whether or not the compositions are homogeneous by solvent fractionation tests. Copol)rmers and blends are not deliberately included in the data presented, but are described in some of the references. (See also some of the closely related elastomeric polymers presented in the entry on Polypropylene, atactic in this handbook.) The criterion of multiple crystallizable blocks per polymer chain may be met in significant fractions of low-tacticity, low-stereoregularity polymers of very high molecular weight. 

Research Associate, Amoco Chemical Company, Naperville, Illinois Polypropylene, atactic Polypropylene, elastomeric (stereoblock) Polypropylene, syndiotactic... 

Chlorinations of polypropylene usually result in severe degradations of the polymer. When TiCU is the chlorination catalyst, presumably, less degradation occurs. Studies of bromination of polypropylene (atactic) show that when the reaction is carried out in the dark, in CCI4 at 60 °C, the substitution reactions proceed at the rate of 0.5% per hour. ... 

Both stmctures exhibit a high degree of crystallinity in contrast to disordered polypropylene (atactic) wherein the methyl group appears randomly in either side of the plane of the chain backbone. 

A-TAB . See Calcium phosphate dibasic Atactic butadiene polymer. See Polybutadiene Atactic poly(acrylic acid). See Polyacrylic acid Atactic polypropylene. See Polypropylene, amorphous Polypropylene Atactic polystyrene. See Polystyrene Atactic poly (vinyl chloride). See Polyvinyl chloride... 

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