Norbomene copolymers

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... 

Several reports in which NHC-Pd complexes have been employed to catalyse the copolymerisation of alkenes with CO have appeared over the years. Herrmann and co-workers reported that the chelating dicarbene complex 38 (Fig. 4.14) is active for CO/ethylene [43], The highest TON [(mol ethylene + mol CO) mol Pd ] was 3 075 after a 4 h run. The modest TONs coupled with a very high molecular weight copolymer led the authors to conclude that only a small fraction of the pre-catalyst goes on to form an active species. Low molecular weight (M = 3 790) CO/norbomene copolymer resulted when complex 39 (Fig. 4.14) was tested by Chen and Lin [44]. The catalyst displayed only a very low activity, yielding 330 turnovers after 3 days. 

Research Focus Synthesis of curable poly(ethylene-co5-ethylidene-2-norbomene) copolymers using a catalyst pair consisting of iron and zirconium metal complexes. 

TABLE 1. Compositional Ratio and Corresponding Physical Properties of Selected Norbomene Copolymers... 

W. Wang and K. Nomura, Remarkable effects of aluminum cocatalyst and comonomer in ethylene copolymerizations catalyzed by (arylim-ido)(aryloxo) vanadium complexes efficient synthesis of high molecular weight ethylene/norbomene copolymer, Macromolecules, 38(14) 5905-5913, July 2005. 

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]...

Albeit these catalysts display a limited stability to water, activities of 3 X lO TO h at room temperature are observed. As with the polymers obtained in traditional polymerization in organic solvents, the materials obtained in water with sal-icylaldimine-based nickel(II) complexes possess a moderate number of methyl branches. Overall, as in the case of the linear polyefhylenes obtained with 6 to 8, the presence of water has no effect on the basic polymer microstructure. Polymer crystallinity can be influenced by employing norbornene as a co-monomer. High molecular weight, amorphous efhylene-norbomene copolymers, which form films at room temperature, can be obtained in aqueous polymerizations [71]. 

In the last fifteen years, ethylene copolymers other than those mentioned above have been produced using metallocene catalysts. These include ethylene-styrene interpolymers, ethylene-norbomene copolymers (a.k.a cyclic olefin copolymers, COC) and EPDM (NORDEL IP from The Dow Chemical Company). 

Fig. 21 Chemical structures of (a) poly(norbomene) copolymer containing CA side groups, (b) the ditopic DAT agent, (c) ditopic Hamilton wedge, and (d) modified wedge. Reprinted with permission from [136], Copyright 2008 American Chemical Society...

Figure 3 UV Spectra of l-pm-thick Films of Alternating Norbomene Copolymers...

Twieg and coworkers, reported preparation of poly(norbomene) copolymers functionalized with nonlinear optical chromophore side groups. Use was made of (ri -toluene)Ni(C6F5)2, catalyst in the polymerization of norbomene. The nickel complex used to polymerize the norbomene monomers is tolerant to many functional groups found in nonlinear optical chromophores. On the other hand, nitriles and amines other than trisubstituted amines strongly inhibit the reaction. A copolymer of hexylnorbomene and a norbomene-functionalized Disperse Red I chromophore was scaled up and studied in detail. Initial studies indicate that electric field poling is effective but that relaxation of polar order in the poly(norbomene) is faster than in a comparable methacrylate copolymer. The copolymer can be illustrated as follows ... 

Tritto, L Marestin, C. Boggioni, L. Sacchi, M. C. Brintzinger, H.-H. Ferro, D. R. Stereoregular and stereoirregular alternating ethylene-norbomene copolymers. Macromolecules 2001, 34, 5770-5777. 

Arndt-Rosenau, M. Beuhch, I. Microstructure of ethene/norbomene copolymers. Macromolecules 1999, 32, 7335-7343. 

Harrington, B. A. Crowther, D. J. Stereoregular, alternating ethylene-norbomene copolymers from monocyclopentadienyl catalysts activated with non-coordinating discrete anions. J. Mol. Catal. A Chem. 1998,128, 79-84. 

Wendt, R. A. Mynott, R. Hauschild, K. Ruchatz, D. Fink, G CNMR studies of ethene-norbomene copolymers. Assignment of sequence distribution using C-enriched monomers and determination of the copolymerization parameters. Macrvmol. Chem. Phys. 1999, 200, 1340-1350. 

Abstract The addition polymeri2ation of norbomene and its derivatives has been carried out in the presenee of a niekel complex or carboxylate and an electron acceptor to obtain amorphous polymers with bicyclic units. Norbomene copolymers with conjugated dienes or ethylene caimot be obtained with these catalysts because of rapid chain transfer reactions. Norbomene can be copolymerized with ethylene under mild conditions in the presence of nickel phosphoiylide chelates without using any cocatalyst. In most cases, the backbone of the resulting copolymer consists of alternating comonomer units. The new catalysts allow ethylene to be copolymerized with norbomene derivatives containing ester substituents. 

The possibility of controlling the interanular wedge angle of ansa-metallocene catalysts and their resulting capability to also enchain olefins, which are otherwise not readily amenable to insertion polymerization, allows the productirMi of copolymers of ethene with cyclic olefins, in particular with norbomene or its substituted derivatives. Based on first observations in this regard [73, 74], ethene/ norbomene copolymers, e.g. with alternating microstmctures [75-77] and with excellent optical and barrier properties, are now commercially produced with ansa-metallocene catalysts by Topas Advanced Polymers (TOPAS ) [78] and by Mitsui Chemical (Apel) [79]. 

Fig. 6 Sequences observed in the NMR spectra of an isoctatic propene-norbomene copolymer with isolated norbomene units, alternating PNP sequences, and 1,2 ot 2,1 and 13 propene insertions...

The first results on 2D-LC for polyolefins were published by Ginsburg et al. [167, 177] and Roy et al. [178]. Roy et al. [178] applied a separation system that was previously described by Macko et al. [158, 159,162]. This system was applied to the separation of ethylene/1-octene copolymers regarding chemical composition and molar mass. Ginzburg et al. [177] used an instrument that has recently been developed and commercialized by PolymerChar (Valencia, Spain). They used the on-line coupling of gradient HPLC and SEC to separate blends of PP stereoisomers, ethylene/propylene mbbers, ethylene/norbomene copolymers and ethylene/1-hexene copolymers, all at an operating temperature of 160°C using a stationary phase of Hypercarb and a mobile phase of 1-decanol-TCB. 

In addition to linear a-olefins, Shino and coworkers reported that 5/MAO catalyzed the living copolymerization of ethylene and norbornene. At 0 °C, 5/MAO can furnish poly(E-co-NB) with 53 mol% norbornene and M = 18 000 g/mol with MJM =1.16 (Hasan et al, 2004b). In addition, a linear increase in with reaction time was observed for this system. At 40 °C, a similar compound, lO/MAO, also provided ethylene-norbomene copolymers with fairly narrow PDls MJM =. 2 -. 21) (Hasan et al, 2004a). 

Hasan, T., Ikeda, T., and Shiono, T. (2004a) Ethene-norbomene copolymer with high nrabomene content produced by nnici-fluorenylamidodimethyltitanium complex using a suitable activator. Macromolecules, 37,8503-8509. 

The effect of introducing norbomene-substituted, pendant POSS moieties onto polynorbomene chains was explored by BharadwaJ et al. using atomistic molecular dynamics simulations (AMDS). The mobUity of the POSS moieties in these copolymers was addressed via the mean squared displacement of the POSS polyhydra in flie norbomene copolymers of 16a and Idb. Computation of the torsional autocorrelation function indicated ttiat conformational dynamics were retarded by the presence of the POSS moieties. The main chain dynamics were sensitive to the presence and tile nature of the attached POSS moieties (at 10 mol % POSS). Chain dynamics were slower in the copolymer with cyclohexyl-substituted POSS pendent groups compared to the copolymer with cyclopentyl-substituted POSS pendant groups. These results are in good agreement with the mechanical properties predicted from AMDS simulations and with the observed Tg values. The simulations predicted... 

H) Alternating ethene-norbomene copolymers by group 4 ansa-metallocenes... 

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