Polymers ethylene-based

In spite of possessing a flexible backbone and low interchain attraction polyethylene is not a rubber. This is because its chain regularity enables a measure of crystallinity which does not disappear until temperatures of the order of 100°C are reached. It therefore follows that if crystallinity can be substantially reduced it should be possible to obtain an ethylene-based polymer which is rubbery. The means by which this objective has been achieved on a commercial scale may be classified into three categories ... 

The sheet comprises a foamed layer (a) composed of polypropylene, at least one surface of which is directly adhered to a substantially unfoamed layer (b) comprising an ethylene-based polymer. The resin employed for the foamed layer is a blend of at least about 50% by weight of polypropylene and from about 3 to less than about 50%... 

Randall, J.C. A review of high-resolution liquid carbon-13 nuclear magnetic resonance characterizations of ethylene-based polymers. J. Mac. Sci. Rev. Macromol. Chem. Phys. 1989, C29, 201-317. 

In crystalline polymers, the principal relaxation process is associated with melting. In polyethylene, a (1-. and 7-transit ions have been identified and, particularly in higb-tlensity polyethylene, the a-transition has been sub-divided into a and a. In ethylene-based polymers, the y-transitions at —120°C is generally associated with the amorphous phase, in particular, with crankshaft motion of methylene sequences. " However, based upon studies of solution grown lamellae, it has also been suggested that this may llien be associated with... 

Figure 30-01. Ethylene-based polymers product regions.f 4i...

Ethylene and its derivatives are the most common monomers for polymers. Write formulas for these ethylene-based polymers ... 

Ethylene-Based Polymers (Written with Prof. Geoffrey W. Coates and Prof. Gregory J. Domski)... 

The catalytic applications of the metal-containing X-Si02-based aerogels has been demonstrated in an important case by Ji [8], who showed that the aerogel in the Pd-form can be reduced and used to catalyze the selective hydrogenation of acetylene in the presence of ethylene about as well as - and perhaps superior to - the known commercial catalysts. Since the methods for the production of ethylene-based polymers employ catalysts that can be poisoned by acetylene, this is a key reaction. Moreover, its selectivity is essential, so that the ethylene itself is not hydrogenated. 

For reviews on NMR analysis of EP copolymers see, for example (a) Bovey, F. A. Mirau, P. A. NMR of Polymers. Academic Press San Diego, 1996. (b) Randall, J. C. A review of high-resolution liquid carbon-13 nuclear magnetic resonance characterizations of ethylene-based polymers. 7. Mac-romol. Set, Rev. Macromol. Chem. Phys. 1989, C29, 201-317. (c) Randall, J. C. Polymer Sequence Determination. Academic Press New York, 1977. (d) For NMR analysis on EP copolymers from metallocenes see, for example Tritto, I. Fan, Z. Q. Locatelli, P Sacchi, M. C. Camurati, I. Galimberti, M. NMR studies of ethylene-propylene copolymers prepared with homogeneous metallocene-based Ziegler-Natta catalysts. Macromolecules 1995, 28, 3342-3350. 

Other ethylene based polymers made by the high pressure process... 

Such a copolymer serves as an excellent example of the introduction of new ethylene-based polymer compositions as a direct result of the development of new catalyst technology. 

FIG. 32 Ethylene-based polymers product regions. (From Ref. 1.)... 

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