Copolymers of norbomene

Ring-Opening Metathesis Polymerization. Several new titanacyclobutanes have been shown to initiate living ring-opening metathesis polymerization (ROMP) systems. These have been used to make diblock and triblock copolymers of norbomene [498-66-8] (N) and its derivatives (eg, dicyclopentadiene [77-73-6] (D)) (Fig. 2) (41). 

A titanacyclobutane carrier for the living ROMP of norbomene can be converted, by reaction with methanol, into an alkyl titanocene methoxide complex which can then be used in conjunction with EtAlCl2 to propagate the ZNP of ethene, so forming a block copolymer of norbomene and ethene620. 

While the homopolymers cannot be processed because of their high melting points there is much interest in the copolymers of norbomene or tetracyclodode-... 

The molybdenum neopentyUdene complex Mo(CHBu )(NR)(OBu )2 is the active catalyst used in a fascinating development for the synthesis of 11-Vt semiconductor clusters (ZnS, CdS, PbS) and silver and gold nanoclusters of predictable size within microdomains in films of block copolymers prepared by ROMP. Block copolymers of norbomene and a functionalized norbomene that wiU complex with a metal-containing compound were prepared and characterized as monodisperse materials. The functionalized component (amine, alkoxide, or thiolate) then sequestered the metal and the metallated block copolymer was cast into a film which was subsequently treated with H2S to convert the metal into the sulfide. The molybdenum complexes have also featured in the development of the synthesis of side-chain liquid crystal polymers by living ROMP.98 99... 

Ethylene-cyclo-olefin copolymers have been known since 1954 (DuPont USP2 721 189) but these materials only became of importance in the late 1990s with the development of copolymers of ethylene and 2-norbomene by Hoechst and Mitsui using metallocene technology developed by Hoechst. The product is marketed as Topas by Ticona. By adjustment of the monomer ratios polymers with a wide range of Tg values may be obtained including materials that are of potential interest as thermoplastic elastomers. This section considers only thermoplastic materials, cyclo-olefins of interest as elastomers are considered further in Section 11.10. 

Ethylene-norbomene copolymers of interest as thermoplastics were discussed in Section 11.6.2. It is however to be noted that copolymers with a norbomene content of about 30 wt% have a glass transition temperature of about 0°C and that copolymers with norbomene contents up to this amount are being evaluated as thermoplastic elastomers... 

Alternating copolymers of ethylene with olefins containing double bonds in the cis configuration, like ds-2-butene, cyclopentene, cycloheptene,115 and norbomene,116 have been described. Recently also copolymers of carbon monoxide with styrene and styrene derivatives, having syndiotactic117 and isotactic118 configurations, have been synthesized and characterized. 

The random copolymer of propylene and ethylene (EP) lacks the good symmetry of it PP and is a flexible elastomer. Since this copolymer is used as an elastomer, it is customary to add a small amount of a diene, such as ethylidene norbomene, to the monomer reactants before polymerization to allow subsequent cross-linking or curing. 

Copolymers of ethylene and norbomene exhibit excellent transparency, high moisture barrier, high strength and stiffness, and low shrinkage. In comparison to poly(ethylene) (PE) and polypropylene) (PP), they show a very low gas permeability. They are used for blister packaging in pharmacy applications and for flexible films for food packaging. Multilayer films consisting of PP outer layers and a cyclic olefin copolymer are in use. 

The fullerene monomer (200), made by the cycloaddition of quadricyclane (199) to Cgo (equation 56), can be copolymerized with an excess of norbomene in the presence of 8 (R = Me) to yield a high-molecular-weight, soluble, film-forming copolymer (86% cis), containing 1% of C60 derivative and exhibiting electronic and electrochemical properties which are typical of the carbon cluster536. 

COC cyclic olefin copolymer amorphous copolymer of 2-norbomene and ethylene (Zeonor)... 

Fig. 20. Dependence of the glass transition temperature of ethene/norbomene copolymers produced by various metallocene/MAO catalysts on the incorporation of norbomene...

Table 23. Properties of a random ethene norbomene copolymer containing 52 mol% of norbomene [105]...

The living ROMP reactions of norbomene and norbomene derivatives have been used to make a variety of polymers possessing unusual properties. Copolymerization of selected fimctionalized norbomenes with norbomene has been used to synthesize star polymers and side-chain liquid crystal polymers. This chemistry has also resulted in the preparation of phase separated block copolymers that contain uniform sized metal or semiconductor nanoparticles. The... 

AES (acrylonitrile-EPDM-styrene) is a blend of SAN and EPDM. SAN is a statistic copolymer of styrene and acrylonitrile. EPDM is an elastomeric terpo-lymer of ethylene, propylene and a nonconjugated diene. The diene studied here was 5-ethylidene-2-norbomene. The total content of EPDM was 34mole% [6]. The diene represented 8 mole% of the EPDM and the SAN phase was composed of 80 mole% of styrene and 20 mol% of acrylonitrile. The AES films were irradiated at / > 300 nm at 60 °C in the presence of oxygen. The photoproducts resulting from the photooxidation of each components of AES were identified by FTIR spectroscopy coupled with the same chemical and physical treatments as mentioned above for the previous studies. As pointed out in the literature [17], the EPDM component is more reactive than the copolymer SAN towards photooxidation. 

Photopolymerization with transition metals [121] has been used for the formation of homopolymers and block copolymers from norbomene (nbn) and phenylacety-lene with W(CO)e (eq. (18) cf. Sections 2.3.3 and 3.3.10.1) [122]. 

In 1975, Du Pont presented an ultra impact strength PA alloy, Zytel-ST, produced by reactive processing of PA66 with maleinated EPDM (copolymer of ethylene, propylene, and 2-ethylidene-5-norbomene) (2). Then followed investigations of... 

Polymerization of acetylenes by metathesis-type catalysts such as M0CI5 and WCle/PluSn was first observed in the 1970s (Woon 1974 Masuda 1974, 1976), but the nature of the chain carrier was then in some doubt. However, it was soon found (i) that metal carbene complexes would initiate the polymerization of MesCC=CH at 60°C (Katz 1980a) (ii) that end-groups derived from such initiators could be detected in polymers of PhC=CH (Kunzler 1988b) and (iii) that triblock copolymers could be made by successive addition of norbomene, acetylene and norbomene to such initiators (Schlund 1989). All types of acetylene can be polymerized in this way and the reactions proceed by a ROMP-type mechanism see Ch. 10. 

When the propagating species are long-lived, it is possible to make block copolymers of controlled chain length by sequential addition of monomers, for example, with ClC=CC4H9/ClC=CCi4H29 and with acetylene/norbomene (see Tables 10.6 and 10.7). 

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