Copolymers ethene

Alternatively, NIR spectroscopy has been applied to relate NIR data to mechanical properties [4], A multivariate data analysis was performed on a series of commercial ethene copolymers with 1-butene and 1-octene. For the density correlation, a coefficient of determination better than 99% was obtained, whereas this was 97.7% for the flexural modulus, and only 85% for the tensile strength. 

Norbornene-ethene copolymer, 16 113 Norbornene-ethylene copolymers, 20 433 physical properties of, 20 420-422 Norbornenodiazetine derivatives, 13 306 Nordel IP (metallocene), 7 637 Nordihydroguaiaretic acid, antioxidant useful in cosmetics, 7 830t Nordstrandite, 2 421, 425 activation, 2 394 classification, 2 422 decomposition sequence, 2 392 from gelatinous boehmite, 2 427 structural properties of, 2 423t NO-reduction reactions, TWC catalyst, 10 49... 

One could also imagine a complex that at one site will insert only one certain type of alkene due to high steric constraints (e.g. ethene) and a second alkene at the other site thus giving an alternating copolymer that may even contain stereoregularity, thus obtaining for instance an alternating norbomene/ethene copolymer [34],... 

Under the same conditions, syndiospecific (Cs-symmetric) metallocenes are more effective for inserting a-olefins into an ethene-copolymer than isospecific working (C2-symmetric) metallocenes, or unbridged metallocenes. In this case hafnocenes are more efficient than zirconocenes, too. 

Very interesting transformations of the polyketones into other polymeric materials have been reported. An optically active isotactic poly[l-oxo-2-mefhylpro-pane-l,3-diyl] was reacted with methylenation reagents to give poly[l-methylene-2-methylpropane-l,3-diyl] ]143] apparently without racemization. A similar material was reduced to the corresponding poly[l-hydroxo-2-methylpropane-l,3-diyl] with 40% 1-diastereoselectivity using tetrabutylammonium borohydride [144]. Furthermore, ethene copolymers or efhene-propene terpolymers were transformed into... 

Many polymers undergo second order transitions at temperatures below T, [224] the transitions are caused by rotations of side groups about an axis which is perpendicular to the chain, by the motion of sequences of 3 — 5 methylenic groups from the backbone or by motion of chain portions in polymers containing heteroatoms in the main chain [162, 226]. The second kind of motion, noted by Schatzki [226] in ethene copolymers and in many homopolymers, is referred to as the crankshaft effect and it occurs immediately below T,. Because it is almost insensitive to the... 

Nearly 40 years have evolved between the first discovery by Reppe of transition-metal-catalyzed CO/ethene copolymerization and the discovery in 1983, at Shell, of a class of highly active, high yield palladium catalysts for the synthesis of high molecular weight, perfectly alternating CO/ethene copolymers [PK-E, Fig. 1], This class of catalysts is also active for the co- and terpol5unerization of CO with alkenes other than ethene, both simple aliphatic and heteroatom functionalized, thus providing access to a family of completely new polyketone polymers. 

Figure 5 Glass transition temperatures of norbornene/ethene copolymers catalyzed with different... 

De Footer and co-workers [25] described a comprehensive C-NMR method for the analysis of composition in the most common commercial polyethylene copolymers. The method covers ethene copolymers with propene, also butene-1, hexene-1, octene-1, and 4-methyl pentene-1 in the composition range of 1-10 mol%. The chemical shift assignments and values of the resonances of the copolymers are presented... 

The activities and the molecular weights of the obtained copolymers are not much influenced by the molar ratio of cyclopentene/ethene in the starting mixture. By low cyclopentene concentrations, there is a weak decrease but at higher concentrations activities are similarly high as for the homopolymerization of ethene. The amount of incorporated cyclopentene increases with decreasing polymerization temperature and increasing ratio of cyclopentene/ethene. Copolymers with 1.7-18 mol.% of cyclopentene units are obtained. The cyclic olefin is incorporated into the copolymer statistically. From the determined rates of incorporation, dependent on the reaction conditions, the copolymerization parameter Vi (how much faster ethene is incorporated than cyclopentene when the last incorporation was an ethene unit) could be calculated to be around 80. The molecular weight distribution (M v/Mn) of the copolymers is 2-4. 

Very recently, Lee and coworkers introduced the copolymerization of ethene with a regioselective partially hydrogenated tricyclopentadiene (HTCPD) by using the same catalytic system IV-6. The monomer reactivity ratios, Te and "htcpd/ were 2.8 and 0.025, respectively. A nearly alternating copolymer with an HTCPD content of 45 mol.% was obtained with a satisfactory activity (4.7 x 10 g (mol Ti)" h ), with a Tg value of 177 °C, significantly higher than that of norbomene/ethene copolymer at the same cycloolefin content. Tensile stress-strain curves showed more ductile properties than a high-Tg E-N copolymer with similar Tg. 

Poly(ethylene-a/r- chlorotrifluoroethylene) Chlorotrifluoroethene-ethene copolymer cthyleiie-trifluoro-chloroethylene copolymer 25101-45-5 Ethene, diloiotrifluoFO-, pol ner with ethene R (C2H4 C2CIF1),... 

Ethene, the most important petrochemical feedstock today, reached a world capacity of about 80 million tons per year in 1995. Almost half is polymerized to give polyethylene. It plays only a secondary role for emulsion polymerization in vinyl acetate-ethene copolymers and in polyethylene waxes. It is important, however, in this connection as a feedstock for the production of vinyl chloride, styrene and vinyl acetate. 

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