Styrene/olefin copolymers

The most common VI improvers are methacrylate polymers and copolymers, acrylate polymers (see Acrylic ester polymers), olefin polymers and copolymers, and styrene—butadiene copolymers. The degree of VI improvement from these materials is a function of the molecular weight distribution of the polymer. VI improvers are used in engine oils, automatic transmission fluids, multipurpose tractor fluids, hydrautic fluids, and gear lubricants. Their use permits the formulation of products that provide satisfactory lubrication over a much wider temperature range than is possible using mineral oils alone. 

Quantitative analysis of copolymers is relatively simple if one of the comonomers contains a readily determinable element or functional group. However, C,H elemental analyses are only of value when the difference between the carbon or hydrogen content of the two comonomers is sufficiently large. If the composition cannot be determined by elemental analysis or chemical means, the problem can be solved usually either by spectroscopic methods, for example, by UV measurements (e.g., styrene copolymers), by IR measurements (e.g., olefin copolymers), and by NMR measurements, or by gas chromatographic methods combined with mass spectroscopy after thermal or chemical decomposition of the samples. 

Such oxometal catalysts can also be immobilized as anions on anion exchange resins as reported recently by Kurusu and Masuyama51 who used tetrabromo-oxomolybdate(V) bound to a tetraalkylammonium-containing styrene/divinylbenzene copolymer as a catalyst for the epoxidation of olefins and oxidation of alcohols with TBHP. 

Since the mid-fifties sulfonated resins based on styrene/divinylbenzene copolymers, initially developed as ion exchangers mainly for water treatment, nave also been used as strongly acidic solid catalysts. Witn few exceptions, industrial application in continuous processes is limited to the manufacture of bulk chemicals, sucn as Disphenol A, (meth)acrylates, metnyl ethers of branched olefins (MTBE, TAME) and secondary alcohols (IPA, SBA). 

In the early 1990s supported metallocenes were introduced to enable gas phase polymerisation. Also ethene/a-olefin copolymers with high comonomer content, cycloolefin copolymers and ethene-styrene interpolymers became available. In 1990 Stevens at Dow [22] discovered that titanium cy-clopentadienyl amido compounds (constrained geometry catalysts) are very beneficial for the copolymerisation of ethene and long-chain a-olefins. 

Styrene/a-olefin copolymers containing a predominant amount of styrene units can be easily formed through the monomer isomerisation-copolymerisation of styrene and /i-olefin such as m-2-butene in the presence of heterogeneous Ziegler-Natta catalysts such as TiCl3—AlEt3. Styrene appeared to be a favourable comonomer for monomer isomerisation-copolymerisation with internal olefins, since only the isomerisation of /i-olefin to a-olefin, and not the isomerisation of styrene (in contrast to the olefin), occurs in the presence of Ziegler Natta catalysts [119] ... 

How can one obtain styrene-rich styrene/ot-olefin copolymers using heterogeneous Ziegler-Natta catalysts Give an example. 

The use of olefin rubbers [18] as good impact modifiers for sPS when used in conjunction with S-B or S-B-S block copolymers, which may be hydrogenated in the butadiene phase, has also been described. Instead of butadiene, isoprene can be used. Examples of the olefinic polymers are polyethylene, ethylene-propylene rubbers (EPR) and polypropylene-(ethylene propylene rubber) block copolymers. Here the styrene block copolymers presumably function as... 

Instead of block copolymers, the use of pseudo-random linear copolymers of an aliphatic a-olefin and a vinyl aromatic monomer has been reported [20], where the styrene content of the polymer must be higher than 40 wt%. Preferred are styrene and ethylene copolymers. These blends may contain, amongst other things, an elastomeric olefinic impact modifier such as homopolymers and copolymers of a-olefins. Presumably the styrene-ethylene copolymer acts as a polymer emulsifier for the olefinic impact modifier. Using 5 wt% of an ethylene-styrene (30 70) copolymer and 20% of an ethylene-octene impact modifier in sPS, a tensile elongation (ASTM D638) of 25 % was obtained. 

As reported by Diehl et al. [58], interpolymers are also compatible with a broader range of polymers, including styrene block copolymers [59], poly(vinyl chloride) (PVC)-based polymers [60], poly(phenylene ethers) [61] and olefinic polymers such as ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer and chlorinated polyethylene. Owing to their unique molecular structure, specific ESI have been demonstrated as effective blend compatibilizers for polystyrene-polyethylene blends [62,63]. The development of the miscibility/ compatibility behavior of ESI-ESI blends differing in styrene content will be highlighted below. 

Ethylene-styrene interpolymers exhibit a novel balance of properties that are uniquely different from polyethylenes and polystyrenes. In contrast to other ethylene-a-olefin copolymers, ESI display a broad range of material response ranging from semicrystalline, through elastomeric to amorphous. The styrenic functionality and unique molecular architecture of ESI are postulated to be the basis of the versatile material attributes such as processability (shear thinning, melt strength and thermal stability), viscoelastic properties, low-temperature toughness and broad compatibility with other polymers, fillers and low molecular weight materials. 

Aqueous dispersions of poly(vinyl acetate) and vinyl acetate-ethylene copolymers, homo- and copolymers of acrylic monomers, and styrene-butadiene copolymers are the most important types of polymer latexes today. Applications include paints, coatings, adhesives, paper manufacturing, leather manufacturing, textiles and other industries. In addition to emulsion polymerization, other aqueous free-radical polymerizations are applied on a large scale. In suspension polymerization a water-irnrniscible olefinic monomer is also polymerized. However, by contrast to emulsion polymerization a monomer-soluble initiator is employed, and usually no surfactant is added. Polymerization occurs in the monomer droplets, with kinetics similar to bulk polymerization. The particles obtained are much larger (>15 pm) than in emulsion polymerization, and they do not form stable latexes but precipitate during polymerization (Scheme 7.2). 

Mn 2 to 4). In olefin polymerization as well as CO copolymerization, a Umited conversion of liquid 1-olefin (co)monomers is yet to be overcome in many cases. As an example of properties that could find potential appUcation, polyolefins contain a negligible proportion of double bonds by comparison to styrene-butadiene copolymers, a hydrocarbon polymer currently prepared by free-radical emulsion polymerization on a large scale. This can result in a considerably higher stability towards UV-Ught and air of polymer films formed from polyolefin latexes. 

The three most important commercial VI improver families each represent one of the most important commercial techniques for manufacturing high molecular weight polymers, thus polymethacrylates by free-radical chemistry, olefin copolymers by Ziegler chemistry and hydrogenated styrene-diene or copolymers by anionic polymerization. 

The homopolymers of 10 were branched and exhibited broad GPC molecular weight distributions. Studies of the homopolymers molecular weights from polymerization at different monomer concentrations while (1) holding the [10]/[I] ratio constant, and (2) employing different [10]/[I] ratios confirmed that major differences existed in homopolymerizations of 10 versus vinylferrocene.56 In ethylacetate the rate law was r = k [M]1 [I]0 5. Polymerizations in benzene exhibited low initiator efficiencies. The rate was three halves order in the concentration of 10, similar to that found for 8.53 Polymers incorporating 10 were able to catalyze the selective 1,4-hydrogenation of methyl sorbate, but not terminal or internal olefins.56 This resembled the catalytic behavior of styrene/r 6-(styrene)tricarbonylchromium copolymers in hydrogenation.75... 

H-NMR studies. Varian A-60 and HR-100 NMR spectrometers were used to measure the 1H-NMR spectra of styrene-methacrylic anhydride copolymers in DMSO-dg solution at 90° and of the derived styrene-methyl methacrylate copolymers in CCli, and C6D6 solution at 75-80°C. Solvent resonances interfered with composition determinations in the case of styrene-methacrylic anhydride copolymers, but the ratio of uncyclized methacrylic anhydride to styrene units (X) could be measured from the relative intensities of resonances observed at 6=5.72 and 6.15 ppm (olefinic protons) and at 6.5-7.5 ppm (aromatic protons). The compositions of the derived styrene/-MMA copolymers were calculated from the proportion of aromatic proton resonance observed in the spectra of copolymers dissolved in CClm as was described previously (6). Letting Y represent the ratio of styrene to MMA units in the derived copolymers, the compositions of the parent styrene-methacrylic anhydride copolymers were calculated as follows ... 

Transition metal complexes, zeolites, biomimetic catelysts have been widely used for various oxidation reactions of industrial and environmental importance [1-3]. However, few heterogenized polymeric catalysts have also been applied for such purpose. Mild condition oxidation catalyzed by polymer anchored complexes is attractive because of reusability and selectivity of such catalysts. Earlier we have reported synthesis of cobalt and ruthenium-glycine complex catalysts and their application in olefin hydrogenation [4-5]. In present study, we report synthesis of the palladium-glycine complex on the surface of the styrene-divinylbenzene copolymer by sequential attachment of glycine and metal ions and investigation of oxidation of toluene to benzaldehyde which has been widely used as fine chemicals as well as an intermidiate in dyes and drugs. 

The rate of polymerization of polar monomers, for example, maleic anhydride, acrylonitrile, or methyl methacrylate, can be enhanced by coraplexing them with a metal halide (zinc or vanadium chloride) or an organoaluminum halide (ethyl aluminum sesqui-chloride). These complexed monomers participate in a one-electron transfer reaction with either an uncomplexed monomer or another electron-donor monomer, for example, olefin, diene, or styrene, and thus form alternating copolymers (11) with free-radical initiators. An alternating styrene/acrylonitrile copolymer (12) has been prepared by free-radical initiation of equimolar mixtures of the monomers in the presence of nitrile-coraplexing agents such as aluminum alkyls. 

High density polyethylene (HOPE) Linear low density polyethylene (LLDPE) Isotactic polypropylene (iPP) Syndiotactic polypropylene (sPP) tram-1,4-Polyisoprene Syndiotactic polystyrene (sPS) Cyclooleflns Ethylene-propylene copolymers Styrene-ethylene copolymers cw -1,4-polybutadiene rrarw -1,4-Poly isoprene Random ethylene-a-olefin copolymers Ethylene-propylene rubber (EPR) Ethylene-propylene-diene copolymers (EPDM)... 

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