Propylene copolymerization

Propylene copolymerization is a remarkable case. Copolymers with molecular weights as high as 800000 are readily obtained. The copolymerization tends toward a product containing two molecules of thiocarbonyl fluoride for each propylene molecule. Compositions with higher thiocarbonyl content can be obtained by use of less propylene in the starting monomer mixture. Products containing approximately 2 1 thiocarbonyl fluoride/propylene ratios are soft, pliable elastomers that retain flexibility to — 55° C. 

Ethylene—Propylene Rubber. Ethylene and propylene copolymerize to produce a wide range of elastomeric and thermoplastic products. Often a third monomer such dicyclopentadiene, hexadiene, or ethylene norbomene is incorporated at 2—12% into the polymer backbone and leads to the designation ethylene—propylene—diene monomer (EPDM) rubber (see Elastomers, synthetic-ethylene-propylene-diene rubber). The third monomer introduces sites of unsaturation that allow vulcanization by conventional sulfur cures. At high levels of third monomer it is possible to achieve cure rates that are equivalent to conventional rubbers such as SBR and PBD. Ethylene—propylene rubber (EPR) requires peroxide vulcanization. 

Athylen-Propylen-Copolymeres (etwa 6 4) 0,34—0,40 Loan, Scanlan... 

Fig. 10. Copolymerization diagrams for ethylene/propylene copolymerization carried out with (Me2C(3-tert-BuCp)(Flu))ZrCl2 at 30 ( ) and 60°C ( ). (120).

Fig. 12. Rate constant kp of the ethylene/propylene copolymerization as a function of the ethylene concentration in the liquid phase at 37° C dashed line, calculated solid line, measured (114).

In order to overcome thfe drawbadr, new types of multi-unsaturated hydrocarbon monomers have been synthedzed in recent years and their behavior in ethylene-propylene copolymerization has been extensively studied. Such mcmomers are characterized by the presence of one unconjugated double bond suitable for copolymerization and of a system of two or three cmijugated double bonds, the high reactivity of which makes them competitive with conventional diene rubbers in sulfur vulcanization despite their low concentration. 

Vanadium(IV) forms complexes with charged carboxylate, aryloxide and alkoxide functionalities as well as the neutral carbonyl group. The steric crowding of the /-butoxides allowed structural characterization of the tetraalkoxide (96) by gas-phase electron diffraction.475 Vw phenoxide complexes derived from ligands such as 2-(dimethylaminomethyl)phenol and 4-chloro-2-[(dimethylamino)methyl]phenol are active as ethylene and propylene copolymerization agents 476 Complexes with silanoxides have been prepared by the oxidation of Vnl complexes.477... 

Table 3. Reactivity ratios reported for ethylene-propylene copolymerization (16)...

Vizen,Ye.V., Kissin, Yu.V. Composition distribution for copolymers in ethylene-propylene copolymerization with the heterogeneous catalyst system VC13-A1(C2H6)3. Vysokomol. Soyed. A, 11, 1774-1782 (1969). - Polymer Sci. USSR A, 11,2017-2028 (1969). 

In a 1990 patent. Wong briefly noted that palladium-based catalysts form optically active propyl-ene/CO copolymers when enantiopure C2-symmetric phosphine ligands 108 and 109 are employed (Scheme 31 Table 5). ° In 1992. Consiglio and co-workers published several papers concerning the use of enantiopure bidentate phosphine ligands in CO/propylene copolymerization.The copolymers formed using... 

Among known Ziegler-Natta catalytic systems catalysts on the base of V and Ti compounds combination with chloroaluminumalkyles are effective for ethylene and propylene copolymerization [176, 177]. It is particularly convenient to use systems on the base of vanadium compounds (tetrachloride, trichloroxide, triacetylacetonate) and diisobutylaluminum chloride. 

At the stage of formation of sites of macromolecules propagation under ethylene with propylene copolymerization initiated by V-Al catalytic systems (separation of fast stage of active sites formation and initiation and slow stage of copolymerization itself) in novel technological scheme of SKEPT production tubular turbulent apparatus is installed (Fig. 6.2, position 6, Fig. 6.4). Calculation of geometry of zone of catalytic system components mixing is also carried out on the base of quantitative dependences obtained in Chapter 3. 

Figure 6.4. Tubular turbulent apparatus for formation of homogeneous high-dispersed sites of macromolecules propagation under ethylene and propylene copolymerization.

Formation of active sited in turbulent regime under ethylene and propylene copolymerization initi-... 

Preparation and introduction into polymerizer of catalytic complex components in tubular turbulent pre-reactor (Fig. 6.4) provides production of copolymer (SKEP and SKEPT) with good and stable in time properties (Table 6,2). Analogously to laboratory results received under separation of stage of formation of active sites and initiation of isoprene polymerization on Ti-Al catalytic system (see 5.3.1) at conditions of industrial production under ethylene of propylene copolymerization increase of copolymer yield and its molecular mass and also decrease of catalyst consumption are observed. 

Fig. 30 Ethylene/propylene copolymerization (gas feed ratio 0.25) with the Ziegler-catalyst system TiCLi/AfEts/extemal donor supported on MgCl2 (0.2 MPa, 50°C) video microscopic snap-shots and kinetic evaluation of six particles...

Ogawa, T. Inaba, T. Gel permeation chromatography of ethylene-propylene copolymerization products. J. Appl. Polym. Sci. 1988, 21, 2979. 

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