NORBORNENE POLYMER

Additional norbornene polymers, (I), were previously prepared by Watanabe et al. (1) and used in films, polarizing plates, and liquid-crystal devices. 

Norbornene polymers or polymers from dicyclopentadiene, respectively, may be formed by the interaction of a cyclic olefin with a ROMP catalyst. Increased reinforcement density provides for extremely high stiffness and strength in poly(norbornene) composites. As catalyst, Phenylmethylene-bis-(tricyclohexylphosphine) ruthenium dichloride is used (30). 

The titanacycle catalyst is also effective in promoting the polymerisation of slightly strained cycloolefins, namely cyclopentene, cycloheptene and cyclooc-tene. The poly(l-alkenylene)s obtained in these polymerisations, however, are characterised by a broadened molecular weight distribution (typically Mw/Mn = 1.2—1.8) compared with that for the norbornene polymer (typically Mw/Mn = 1.08-1.2) [99],... 

Barrett et al. [150] have used ROM-CM to attach ROMP norbornene polymers to vinyl-PS via resin-bound catalyst 77 (Scheme 25). For further examples of ROM-CM of norbornene derivatives on solid supports see Ref. [151]. The... 

When cyclic alkenes are utilized as starting materials the metathesis reaction will lead to long chain polymers and/or cyclic oligomers [103, 104, 107, 108]. If a strained cyclic alkene is employed the reaction is effectively irreversible. Industrially cyclooctene (polymer Vestenamer), 2-norbornene (polymer Norsorex), and dicyclopentadiene (polymer Telene, Metton, Pentam) are used as monomers. Upon polymerization cyclooctene and 2-norbornene yield straight chain polymers while dicyclopentadiene also allows cross-linking (Scheme 5.56). 

Stabilization of the mesophase was observed as the degree of polymerization was increased. The Tg values of the poly(norbornene)-polymers were about 30 °C higher than those of the poly(butadiene) polymers. Both polymers showed similar isotropization temperatures, but they differed substantially in their liquid crystalline behaviors. Poly-(IX-n)s with a poly(norbornene) backbone exhibited textures typical of nematic mesophases, whereas the poly-(butadiene)-based polymers poly-(X-n) displayed textures representative of smectic A mesophases. The more flexible backbone of poly(butadiene) allowed a higher order of alignment of the mesogenic units, resulting in the more ordered liquid crystalline smectic A phase. 

Transition metal catalyzed, ring opening polymerization Dispersion, cationic polymerization Homogeneous/precipitation, cationic polymerization Homogeneous, free radical/cationic polymerization Precipitation, free radical polymerization Dispersion, free radical polymerization Norbornene polymer, polycarbonate Isobutylene polymer Vinyl ether polymer Amorphous fluoropolymers Vinyl polymer, semicrystalline fluoropolymers Polyvinyl acetate and ethylene vinyl acetate copol5Tner... 

This review will attempt to cover all of these polymer types, in particular with reference to developments involving late transition metals. However, there will be a major emphasis on norbornene polymers for a variety of reasons ... 

From the spectra, it is clear that the dimer with m/z 216 is a norbornene dimer terminated with a vinyl group (dimer-4, 113.36 and 141.91 ppm). The compound with m/z 244 is a norbornene dimer with an ethyl and a vinyl group at the head (14.11 and 22.18 ppm) and the tail (113.72 and 142.87 ppm) of the molecule (di-mer-5), respectively. Assignments have been made based on analysis of a C 2D-INADEQUATE spectrum and are presented in Fig. 4.18. Both dimers are enchained in the 2,3-fashion consistent with the proposal based on the NMR analysis of the norbornene polymer made with naked nickel . 

Fig. 4.23 Effect of 1 -olefin chain transfer agents on norbornene polymer using the multicomponent catalyst, Ni(O2CR)24-9 BEt3 Et20-r 1 OAlEts.

After insertion of ethylene occurs, presumably subsequent to coordination to Ni, a (CgFjjNi-CHz-CHz-capped norbornene polymer intermediate is formed. Free rotation about the -CH2-CH2- bond of this intermediate offers two /Miydro-gens that can be readily eliminated to form a neutral NiHfCgFs) species and a vinyl-terminated polynorbornene chain. A similar hydride intermediate has been proposed by Klabunde for the dimerization of ethylene and propylene [61]. 

Finally, the ethylene/norbornene copolymers obtained using the nickel catalysts are essentially indistinguishable from those obtained using metaUocene-based early transition metal catalysts, both in terms of the microstructure and such physical properties as Tg and tensile modulus. For the ethylene/norbornene polymers synthesized, the glass transition temperature (Tg) increases smoothly with increasing norbornene content. 

Polymers for use in 193 nm lithography are co-, ter-, and tetra-polymers of 1) methacrylates, 2) norbornenes, 3) norbornene-maleic anhydride, 4) nor-bornene-sulfur dioxide, and 5) vinyl ether-maleic anhydride (Fig. 39). While 1), 3), 4), and 5) are prepared by radical polymerization, all-norbornene polymers 2) are synthesized by transition-metal-mediated addition polymerization [166-168].Norbornenes (Fig.40) are sluggish to undergo radical [168,169] and cationic [170] polymerizations. Their ring-opening metathesis polymerization (ROMP, Fig. 40) [ 171 ] has never produced worthy resist polymers. The C=C double bonds introduced in the ROMP polymer backbone must be hydrogenated to reduce the 193 nm absorption and the ROMP polymers tend to have low Tg. However, the major problem for the ROMP polymers was their unacceptable swelling in aqueous base development. While polymethacrylate systems contain etch-resistant alicyclic structures in the ester side chain, norbornene-based systems carry the alicyclic unit in the backbone. Essentially all the 193 nm re-... 

Interestingly, this same norbornene polymer had been patented two years earlier by Anderson and Merckling at DuPont using a mixture of titanium compounds as the metathesis initiator (see U. S. Patent 2,721,189, 1955 [Chem. Abst. 1956, 50, 14596]). At the time, however, they did not realize that this polymer was unsaturated, a result that would not be disclosed until much later W.L. Truett, D.R. Johnson, I. M. Robinson, B. A. Montague, J. Am. Chem. Soc. 1960, 82, 2337. 

Y. Yampol skii, N. B. Bespalova, E. S. Finkel shtein, V. I. Bondar, A. V. Popov, Synthesis, gas permeability, and gas sorption properties of fluorine containing norbornene polymers. Macromolecules, 27, 2872-2878 (1994). 

Arndt, M. Gosmann, M. Transition metal-catalyzed polymerization of norbornene. Polym. Bull. 1998, 41, 433 40. 

Biagini, S. C. G. Coles, M. P. Gibson, V. C. Giles, M. R. Marshall, E. L. North, M. Living ling-opening metathesis polymerization of amino ester functionahzed norbornenes. Polymer 1998, 39, 1007-1014. 

INVESTIGATION OF THE MICROSTRUCTURE OF METAL CATALYZED CYCLOPENTENE CO-NORBORNENE POLYMERS BY SPECTRAL METHODS... 

As with homopolymers, block copolymers may incorporate metals such as in the work of Chan and Schrock where palladium-containing norbornene moieties were copolymerized and the metal reduced below the Tg of the polymer to afford metal clusters whose size was modulated by the polymeric composition. Even with fairly labile metals, the gentle reaction conditions of ROMP can incorporate them into polymeric networks. The ROMP of a variety of norbornene derivatives bearing cationic iron moieties was accomplished without loss of the iron, whereas heating above 100 °C resulted in loss of the iron without degradation of the polymer. The norbornene polymer sans iron was also realized via photolysis. ... 

---