Copolymers of ethene

The investigation of propylene and norbornene as comonomers is straightforward, since the respective copolymers have been expected to exhibit higher glass transition temperatures than the copolymers of ethene because of the higher glass transition temperature of propene in comparison to ethylene. 

Of great industrial interest are the copolymers of ethene and propene with a molar ratio of 1/0.5, up to 1/2. These EP-polymers show elastic properties and, together with 2-5 wt% of dienes as third monomers, they are used as elastomers (EPDM). Since they have no double bonds in the backbone of the polymer, they are less sensitive to oxidation reactions. As dienes, ethylidenenorbomene, 1,4-hexadiene, and dicyclopentadiene are used. In most technical processes for the production of EP and EPDM rubber in the past, soluble or highly disposed vanadium components are used [69]. Similar elastomers can be obtained with metallocene/MAO catalysts by a much higher activity which are less colored [70-72]. The regiospecificity of the metallocene catalysts toward propene leads exclusively to the formation of head-to-tail enchainments. The ethylidenenor-bornene polymerizes via vinyl polymerization of the cyclic double bond and the tendency to branching is low. The molecular weight distribution of about 2 is narrow [73]. 

Polyethersiloxancs have surfactant properties. They ate utilized in large quantities as foam stabilizers in the manufacture of polyurethane hard and soft foams, the polyether component for this application being a copolymer of ethene oxide and propene oxide. Polyethersiloxancs are, however, also used in antifoaming formulations, as a gloss and deaeration additive in paints and as textile auxiliaries. 

Y. Akpalu, L. Kielhorn, B.S. Hsiao, R.S. Stein, T.P. RusseU, J. van Egmond and M. Muthukumar, Structure development during crystaUization of homogeneous copolymers of ethene and 1-octene Time-resolved synchrotron X-ray and SALS measurements, Macromolecules 32, 765-770 (1999). 

The Tg values are raised with a bulkier cycloolefin, regarding the same incorporation rate of 30% (norbornene T =12°0, DMON 7 g = 105°Q. The highest glass transition temperature with 229 °C was reached by a copolymer of ethene and 5-phenylnorbornene. 

The possibility of controlling the interanular wedge angle of ansa-metallocene catalysts and their resulting capability to also enchain olefins, which are otherwise not readily amenable to insertion polymerization, allows the productirMi of copolymers of ethene with cyclic olefins, in particular with norbomene or its substituted derivatives. Based on first observations in this regard [73, 74], ethene/ norbomene copolymers, e.g. with alternating microstmctures [75-77] and with excellent optical and barrier properties, are now commercially produced with ansa-metallocene catalysts by Topas Advanced Polymers (TOPAS ) [78] and by Mitsui Chemical (Apel) [79]. 

Nch20h was demonstrated. Activities, as well as incorporation of functionalized monomers, of bimetallic catalysts were three- to fourfold higher than that of the monometallic analogue in identical conditions. Interestingly, the molar masses of copolymers were similar to those of copolymers of ethene with norbomene. Attempts to copolymerize Ncooh faded because the high acidity of the comonomer leads to catalyst deactivation. 

Phosphine Sulfonate-Based Catalysts Synthesis of Linear Copolymers of Ethene and Functionalized Olefins 816... 

Hie recently developed tridentate titanium complexes 47 and 48 (Figure 21) base on the same principle, the incorporation of an electron donating ligand, which reduces the Lewis acidity of the titanium center. Hiese catalysts are able to produce copolymers of ethene and functionalized... 

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