Polynorbomenes

Natural mbber comes generally from southeast Asia. Synthetic mbbers are produced from monomers obtained from the cracking and refining of petroleum (qv). The most common monomers are styrene, butadiene, isobutylene, isoprene, ethylene, propylene, and acrylonitrile. There are numerous others for specialty elastomers which include acryUcs, chlorosulfonated polyethylene, chlorinated polyethylene, epichlorohydrin, ethylene—acryUc, ethylene octene mbber, ethylene—propylene mbber, fluoroelastomers, polynorbomene, polysulftdes, siUcone, thermoplastic elastomers, urethanes, and ethylene—vinyl acetate. 

Of these various groups there was extensive interest for some years in polyalkenamers such as frani -polypentenamer which has now abated whilst interest in polynorbomene is steadily increasing. Since the chemistry and technology of the two types is somewhat different each type will be dealt with separately. A third group comprises the chlorine-containing polymers announced by Goodyear in 1980. 

Polynorbomene is also of interest to the plastics processor since by using a dry blending process for mixing and a modified injection moulding process for fabricating, the use of conventional rubber-processing equipment may be avoided. 

Polynorbomene (PNR), polyoctenamer and hydrogenated nitrile rubber (HNBR)—this chapter... 

With the growing interest for the polynorbomene, photoresist polymer, and cyclic olefin copolymer, the synthesis norbornene or bicyclo[2,2,l]-2-heptene (NBN) has drawn significant attention because it is one of the most important precursor for these materials. Norbornene is produced by the reaction between ethylene and cyclopentadiene (CPD) via the Diels-Alder condensation process at elevated temperature and pressure [1,2]. 

Mayr, B., Holzl, G., Eder, K., and Buchmeiser, C. G., Hydrophobic, peUicular, monolithic capillary columns based on cross-linked polynorbomene for biopolymer separations. Analytical Chemistry 74(23), 6080-6087, 2002. 

Random polynorbomene-based terpolymer 5 (Fig. 5.8) functionalized with SCS palladated pincer complexes, dibenzo[24]crown-8 (DB24C8) rings, and 2,6-diaminopyridine units was synthesized by ROMP (South et al. 2006). The palladium complex serves as the anchoring unit for metal coordination, 2,6-diaminopyridine as the DAD hydrogen bonding moiety, and DB24C8 as the precursor for pseudorotaxane formation, which has been smdied extensively by Stoddart and his group... 

N.G. Gaylord and A.B. Deshpande, Structure of vinyl-type polynorbomenes prepared with Ziegler-Natta catalysts,. Polym. Sci., Polym. Lett. Ed., 14 613-617, October 1976. 

J.E. McKeon and P.S. Starcher, Novel polynorbomenes, process for production thereof, and products produced therefrom, US Patent 3 330 815, assigned to Union Carbide Corp, July 11,1967. 

Among others, it can be used in ring-opening metathesis polymerization to produce polynorbomene the oldest polyalkenamer (see Section 12.3). Cycloaddition of... 

Polynorbomene the oldest polyalkenamer is manufactured by a method developed by CDF Chimie156 157 since 1976. Tungsten or rhodium catalysts are used to yield a highly trans polymer. This is capable of rapidly absorbing hydrocarbon oils and can be crosslinked to produce a very soft rubber. 

Copolymerizations of benzvalene with norbornene have been used to prepare block copolymers that are more stable and more soluble than the polybenzvalene (32). Upon conversion to (CH), some phase separation of nonconverted polynorbomene occurs. Other copolymerizations of acetylene with a variety of monomers and carrier polymers have been employed in the preparation of soluble polyacetylenes. Direct copolymerization of acetylene with other monomers (33—39), and various techniques for grafting p oly acetylene side chains onto solubilized carrier polymers (40—43), have been studied. In most cases, the resulting copolymers exhibit poorer electrical properties as solubility increases. 

Amphiphilic star-block copolymers can be prepared by adding a polycyclic diene such as 238 to a living diblock copolymer made by sequential ROMP of (i) the monomer in Table 9 with R = COOSiMe3, and (ii) norbomene. The trimethylsilyl ester groups are then converted to carboxylic acids by soaking the cast film of the polymer in water for 2-3 days to give a product with a hydrophobic core of polynorbomene and a hydrophilic outer layer126,502. 

A preceramic, carrier polymer route to boron carbide has been reported via the pyrolysis of a polynorbomene that bears decaborane side groups.69 An important feature of this development is the ability to produce nanofibers of boron carbide in the following way. A solution of the poly(norbomenyldecaborane) in THF is subjected to the process of... 

The proposed idea that metal alkyhdene complexes are be able to catalyze olefin metathesis was confirmed in 1980 [8] and consolidated in 1986 by Schrock with the development of the first well-characterized, highly active, neutral tungsten (Cl, Fig. 3) [9] and molybdenum (C2) [10] alkylidene complexes. These complexes were able to catalyze both the metathesis of different olefins and the ROMP of functionalized norbomene to polynorbomene with low polydispersities [11]. Moreover, these catalysts were used by Wagener and coworkers to perform the first quantitative ADMET polymerization [12] and copolymerization [13] of 1,5-hexadiene and 1,9-decadiene. However, the low stability of these catalysts in... 

Mizuno, K., Ueno, T., Hirata, A., Ishikawa, T., and Takeda, K., Thermal degradation and flame retardancy of polynorbomene by a zeolite, Polym. Degrad. Stab. 2007, 92, 2257. 

In addition to block copolymer synthesis by subsequent polymer growth along one polymer chain, Eq. (21), and the reaction sequence of Eqs. (19, 22—24), preformed polymer blocks can be linked via reactive end groups. Polynorbomene with one titanacyclobutane end group was reacted in a Wittig-type reaction with... 

Schrock, Gibson et al. [52d] found that styrene and 1,3-pentadiene could be used as chain transfer reagents for the living ring-opening olefin metathesis polymerization of norbornene with molybdenum based catalyst 35a. Renewed norbornene addition to a polymerization mixture containing initiator 35a and 30 equivalents of styrene resulted in the formation of polynorbomene with a low polydispersity and a molecular weight controlled by the number of norbornene equivalents in each of the individual monomer solutions, Eq. (38). This method allows a more efficient use of the catalyst. 

Using the ROMP catalyst bis(tricyclopentylphosphine)dichloro-(3-methyl-2-butenylidene)-ruthenium, (IV), Piccinelli [3] prepared low molecular weight polynorbomene derivatives functionalized with hydrophilic polyethers, (V), which were subsequently hydrogenated, (VI), as illustrated in the second equation. 

Although, in th case, extractive distillation provides a solution in itself, it may be interesting to improve its effectiveoeu by avoiding complications of this type, especially since cydopentadiene. and. to a lesser degree, piperylene, have many specific appHcadons. The former is used for elastomers (EPDM, polynorbomene. transpolypentenamer etc). 

Concurrent with the development of the mechanistic explanations for the chemistry has been the creation of new polymers based on ROMP chemistry. While a wide variety of strained cyclic monomers have been polymerized with a significant emphasis on monomer stmcture/reactivity relationships, three ring structures deserve special attention, since they are or have been produced on a commercial scale. These polymers are polyoctenamer (from cyclooctene), polynorbomene (from... 

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