Olefin polymers, commercially available

Ethylene has also been copolymerised with a number of non-olefinic monomers and of the copolymers produced those with vinyl acetate have so far proved the most significant commercially . The presence of vinyl acetate residues in the chain reduces the polymer regularity and hence by the vinyl acetate content the amount of crystallinity may be controlled. Copolymers based on 45% vinyl acetate are rubbery and may be vulcanised with peroxides. They are commercially available (Levapren). Copolymers with about 30% vinyl acetate residues (Elvax-Du Pont) are flexible resins soluble in toluene and benezene at room temperature and with a tensile strength of about lOOOlbf/in (6.9 MPa) and a density of about 0.95 g/cm. Their main uses are as wax additives and as adhesive ingredients. 

An alternative method for the preparation of polymer-chained pendant ligands has been recently developed.102 The polymerization of the (R)-hydroxylpiperidinyl fragment was realized by ROMP of a bicyclic olefin with the commercially available Grubbs catalyst. 

Several combinatorial approaches to the discovery of transition metal based catalysts for olefin polymerization have been described. In one study Brookhart-type polymer-bound Ni- and Pd-(l,2-diimine) complexes were prepared and used in ethylene polymerization (Scheme 3).60,61 A resin-bound diketone was condensed with 48 commercially available aminoarenes having different steric properties. The library was then split into 48 nickel and 48 palladium complexes by reaction with [NiBr2(dme)] and [PdClMe(COD)], respectively, all 96 pre-catalysts being spatially addressable. 

Another class of "chain scission" positive resists is the poly(olefin sulfones). These polymers are alternating copolymers of an olefin and sulfur dioxide. The relatively weak C-S bond is readily cleaved upon irradiation and several sensitive resists have been developed based on this chemistry (49,50). One of these materials, poly(butene-l sulfone) (PBS) has been made commercially available for mask making. PBS exhibits an e-beam sensitivity of 1.6 pC cm-2 at 20 kV and 0.25 pm resolution. 

Knowledge of the coordination polymerisation of olefins would not be complete without consideration of the types of process used in industry for polyolefin manufacture. Problems encountered in production influence developments in the area of catalysis in olefin polymerisation, an improvement in a catalyst being defined as leading to a reduction in the cost of making the polymer or giving better product properties. Therefore, the principal types of polyolefin production involving coordination catalysts of various types are dealt with briefly. Since modern polyolefin production processes offer a versatile range of polymers, the main commercially available olefin polymerisation products and their typical uses are also considered. 

Table 3.9 lists the main commercially available olefin polymers synthesised by coordination polymerisation and their typical uses [556],... 

Nitroxide-mediated polymerizations have recently been used to polymerize diene-based monomers [159]. ATRP [79] has so far been less successful and therefore other routes to incorporation have been utilized. One route is to functionalize a commercially available olefin based polymer. Kops et al. reacted a hy-... 

The high oxophilicity of early transition metal catalysts (titanium, zirconium, or chromium) causes them to be poisoned by most functionalized olefins, particularly the commercially available polar comonomers. However, there are examples of copolymerizations with special substrates or with very high levels of a Lewis acid incorporated into the polymerization system to protect the polar functionality through complexation. " Alternative routes to polar copolymers involving metathesis of cyclic olefins and functionalization of the resulting unsaturated polymer or metathesis of polar cycloolefins followed by hydrogenation to remove the resulting unsaturation have been published.The cost of these multistep... 

The copolymerization of ethylene and carbon monoxide to give alternating copolymers has attracted considerable interest in both academia and industry over recent decades [1, 2]. Attention was focused on aliphatic polyketones such as poly(3-oxotrimethylene) (1) because of the low cost and plentiful availability of the simple monomers. The new family of thermoplastic, perfectly alternating olefin/ carbon monoxide polymers commercialized by Shell provides a superior balance of performance properties not found in other commercial materials the an ethylene/ propene/CO terpolymer is marketed by Shell imder the tradename Carilon . About the history of polyketones see Refs. [3-11],... 

The preparation of ionomers involves either the copolymerization of a functionalized monomer with an olefinic unsaturated monomer or direct functionalization of a preformed polymer. Typically, free-radical copolymerization of ethylene, styrene, or other a-olefins with acrylic acid or methacrylic acid results in carboxyl-containing ionomers. The copolymer, available as a free acid, is then neutralized partially to a desired degree with metal hydroxides, acetates, or similar salts. The second route for the preparation of ionomers involves modification of a preformed polymer. For example, sulfonated polystyrene is obtained by direct sulfonation of polystyrene in a homogeneous solution followed by neutralization of the acid to the desired level. Some commercially available ionomers are listed in Table 15.17. 

In general, the two polymer phases are incompatible. For this reason, a compatibilizer must be added to the blends in order to achieve good dispersing and mutual anchoring of the two polymer phases. Suitable compatibilizers are carboxylated or anhydride grafted poly(olefin)s. Such compatibilizers are generally commercially available, e.g.. Polybond , Exxelor , Hostamont , Admer , Orevac , Epolene , and Hostaprime [13]. 

Crystalline polyolefins as polypropylene (PP) with high tacticity and copolymers of propylene with ethylene and/or higher a-olefins containing sufficiently long isotactic PP blocks can only be dissolved under conditions (solvent/temperature) which cause complete melting of the crystalline domains. Therefore, SEC of PP and crystalline copolymers of propylene must be carried out at elevated temperatures which requires the special equipment of high-temperature SEC (HT-SEC) which is commercially available from several sources, e.g. Millipore-Waters Corp. (Milford, MA, USA) and Polymer Laboratories Ltd (Church Stretton, Shropshire, UK). 

The reaction of the vanadium salt with the aluminum alkyl leads to displacement of the vanadium ligands, with the formation of V-C bonds. As a consequence, the catalytic site is not sterically demanding. As mentioned above, vanadium-based catalysts behave as SSCs for olefin polymerization. Although the structure of their active catalytic sites is still unknown, the structures of polymers produced with vanadium systems are typical of those from SSCs. The majority of commercially available EP(D)M grades are from vanadium-based catalysts. ... 

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