Ethylene-propylene characterization

The most important olefins used for the production of petrochemicals are ethylene, propylene, the butylenes, and isoprene. These olefins are usually coproduced with ethylene by steam cracking ethane, LPG, liquid petroleum fractions, and residues. Olefins are characterized by their higher reactivities compared to paraffinic hydrocarbons. They can easily react with inexpensive reagents such as water, oxygen, hydrochloric acid, and chlorine to form valuable chemicals. Olefins can even add to themselves to produce important polymers such as polyethylene and polypropylene. Ethylene is the most important olefin for producing petrochemicals, and therefore, many sources have been sought for its production. The following discusses briefly, the properties of these olefmic intermediates. 

This is a nonpolar rubber with very little unsamration. Nanoclays as well as nanotubes have been used to prepare nanocomposites of ethylene-propylene-diene monomer (EPDM) rubber. The work mostly covers the preparation and characterization of these nanocomposites. Different processing conditions, morphology, and mechanical properties have been smdied [61-64]. Acharya et al. [61] have prepared and characterized the EPDM-based organo-nanoclay composites by X-ray diffracto-gram (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy... 

Pearson D.S. and Graessley W.W., Elastic properties of well characterized ethylene propylene copol3Tner network. Macromolecules, 13, 1001, 1980. 

Curve El in Fig. 2.21 corresponds to an elastomer (statistic copolymer from ethylene and propylene), characterized by a low value of the elastic modulus... 

EPDM-g-PMMA was produced through ATRP with CuBr/bipyridine [80]. The graft copolymer, which had an ethylene-propylene terpolymer (EPDM) backbone and PMMA branches, was prepared from brominated EPDM that was produced with NBS to introduce allylbromine moiety on the backbone. Resulting EPDM-g-PMMA graft copolymers were characterized by solvent extraction, infrared (IR), and NMR techniques. 

The products of reduction of salt anions are typically inorganic compounds like LiF, LiCl, Li20, which precipitate on the electrode surface. Reduction of solvents results, apart from the formation of volatile reaction products like ethylene, propylene, hydrogen, carbon dioxide, etc., in the formation of both insoluble (or partially soluble) components like Li2C03, semicarbonates, oligomers, and polymers.281 283 359 A combination of a variety of advanced surface (and bulk) analytical tools (both ex situ and in situ) is used286-321 332 344 352 353 360-377 to gain a comprehensive characterization... 

Figure 3.41. Structure of carbon paper (left) and carbon cloth (right) used for gas diffusion layers in PEM fuel cells. A coating of 20% (by weight) fluorinated ethylene propylene has been applied. (From C. Lim and C-Y. Wang (2004). Effects of hydro-phobic polymer content in GDL on power performance of a PEM fuel cell. Electro chimica Acta 49, 4149-4156 G. Lu and C-Y. Wang (2004). Electrochemical and flow characterization of a direct methanol fuel cell.. Power Sources 134, 33-40. Used with permission from Elsevier.)...

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. 

The MAO-activated 138 and 137, effective in the living homopolymerization of ethylene and propylene, also promote their block co-polymerization. This approach broadens remarkably the utility of living catalysts because it allows the preparation of block co-polymers with high glass or melting transition blocks from common commercial monomers such as ethylene and propylene. These materials could have applications as compatibilizers and elastomers.1232,1233 Using complex 138, propylene has been first homopolymerized to sPP for 2h in toluene at 0°C (Mn = 38400 Mw/Mn = 1.11). Then, an ethylene overpressure was applied, and in 1 additional h an sPP-/W< (j -poly(E-r -P) diblock co-polymer was obtained (Mn = 145 100, A/w/A/ = 1.12). The microstructure of this diblock co-polymer is shown in Scheme 48. This co-polymer has a Tm of 131 °C while the ethylene-propylene block (E = 33 mol%) has a TR of —45 °C.1175 A detailed morphological and thermodynamic characterization of these co-polymers has been reported.1234... 

Catalysts based on the Hf pyridyl amine complexes 126-128 have been used for the preparation of ethylene/ propylene co-polymers as well as of ethylene/propylene/l-octene terpolymers. These co-polymers are characterized by having at least 60 wt% propylene units, Mw around 300000, and Mw/Mn in the range 2.0-2.4. The NMR analysis of these co-polymers showed that the propylene sequences are remarkably isotactic mm > 90%) and showed the presence of regioirregularly inserted propylene units(<0.5% mol). The most interesting property of catalysts based on 126-128 is their high thermal stability.1119 Using modifications of isospecific bis(phenoxy-amine)-based catalysts, such as complex 164, the controlled synthesis of iPP- /orjf-poly/E-co-P) diblock co-poly-mers has been achieved. This is a remarkable result since iPP and PE are both polymeric materials of extreme industrial relevance.1206... 

Moore, C.G. Trego, B.R. Structural characterization of vulcanizates. Part IV. Use of triphenylpho-sphine and sodium di-n-butyl phosphite to determine the structures of sulfur linkages in natural rubber, cis-l,4-polyisoprene, and ethylene-propylene rubber vulcanizate networks. J. Appl. Polym. Sci. 1964, 8, 1957. 

Figure 14.10. Rate of flame spread vs. loading of huntite/liydromagnesite filler in ethylene-propylene copolymer. [Data fi om Toure B. Lopez-Cuesta J, Benhassaine A, Crespy A, ]nt. J. Polym. Analysis and Characterization, No.3, 1996, 193-202.]...

Polymer (B) Characterization Solvent (A) ethylene/propylene copolymer M /kg.mor = 0.78,M ,/kg.mor = 0.79, 50 mol% propene, alternating ethylene/propylene units from complete hydrogenation of polyisoprene 1-butene C4H8 1992CH1 106-98-9... 

Molar mass distribution is a dominant microstracture parameter that, in copolymers, needs to be measured with additional information to account for long chain branching, comonomer incorporation, or ethylene propylene combinations (in the case of EP copolymers). The combination of GPC and IR spectroscopy has been shown to be of great value in the characterization of copolymers. The importance of automation and sample care, especially in the case of polypropylene, has been discussed as well as the significant improvement in sensitivity by the use of IR MCT detectors. There are big expectations for the analysis of ultrahigh molar mass polyolefins by the new AF4 technology. 

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