SI-ROMP

NBE strands from the surface [180]. Furthermore, anodization lithography was used to prepare nano-patterned polymer brushes on silicone [181], and the resulting nano-particles were functionalized by SI-ROMP [182]. SI-ROMP has been conducted using low-strain monomers such as CPE or cyclododecene to prepare polymer brushes [183]. SI-ROMP has also been conducted on cellulose fibers [184] as well as for the preparation of functional supports and materials [185-187]. 

Graphical representation of the preparation of ferrocene-functionalized polymer brushes grafted on gold nanoparticles via SI-ROMP. (Reprinted with permission from Watson et at. 1999. Hybrid nanoparticles with block copolymer shell structures. Journal of the American Chemical Society 121 (2) 462-463, copyright (1999) American Chemical Society.)... 

Graphical representation of the preparation of ferrocene-functionalized polymer brush arrays via SI-ROMP by DPN. (Reproduced from Liu et al. 2(X)3. Surface and site-specific ring-opening metathesis polymerization initiated by dip-pen nanolithography. Angewandte Chemie-lnternational Edition 42 (39) 4785-4789 with permission from Wiley.)... 

A third access to soluble polyenes lies in the ROMP of cyclooctatetraene (COT) derivatives. COTs are readily polymerized by W- and Mo-based Schrock carbenes to yield substituted polyenes (Scheme 36). As evidenced by UV—Vis spectroscopy, these materials which are synthesized in a predominately cis form are highly conjugated with values for Amax of up to 538 nm (R = />octadecyl). Thermal cis—trans isomerization is possible and may be monitored via UV— Vis spectroscopy. The resulting predominately all-trans polymers show values for Xmax of up to 634 nm (R = neopentyl). Upon doping of these materials with iodine, conductivities of up to 50 S/m may be achieved.Trimethylsilyl-substituted COT forms transparent polymers, which may be casted onto n-doped silicon (n-Si). Upon treatment with iodine, surface barrier solar cells may be prepared. Soluble,... 

Metathesis catalysts, e.g., tungsten chlorides in combination with Si(CH2CH=CH2)4 [378] or AlEt3/benzoyl peroxide [379], lead to high-cis polymers in the ROMP of cyclopentene. A high cis-polypentenamer is also obtained under use of M0CI5 and AlEt3 [380]. 

Abstract The presented paper is a summary of our results on synthesis and polymerization of silyl-containing norbomenes and norbomadienes via ring-opening metathesis polymerization (ROMP) and addition processes as well as ring-opening polymerization (ROP) of silacyclobutanes and disilacyclobutanes. The synthesis of heterochain and carbochain polymer families with regularly varied substituents at Si atom and various number and location Si(CH3)3-substituents has been realized. Systematic study of gas transport parameters of polycarbosilanes series of different classes allowed us to find out real eorrelations between features of chemical polymer structure and its gas separation eharacteristics. 

This part of the review is devoted to PCSs prepared from silicon-carbon cyclic compounds. In the first section, we will consider the polymerization of saturated and unsaturated silicon-carbon heterocycles (SCHs) via a Si-C bond rupture (ringopening polymerization, ROP) and of unsaturated SCHs via a chain C=C bond rupture (ring-opening metathesis polymerization, ROMP). The polymerization of silicon homocycles is beyond the scope of this review since polymers containing only Si atoms in the backbone belong to a special branch of organosiUcon chemistry. 

There is no large strain in silaindan and silacyclopentene structures containing sp -carbon atom in benzyl or allyl position with respect to the silicon. Therefore, the driving force of the catalytic ROP of the above monomers is the combination of a small strain with the presence of chemically active endocyclic Si-Cfienzyi or Si-CAllyl bonds. The existence of two active moieties in silacyclopentene molecules (the unsubstituted double bond and the Si-CAHyi bond) provides two ways for polymerization via rupture of endocyclic Si-C bonds (cationic and anionic ROP) and via metathesis polymerization by cleavage of endocyclic C=C bonds (ROMP). 

Earlier it was shown that the presence of Si-C- and Si-H-fragments in unsaturated substrates did not prevent their metathesis including ROMP. Therefore, many original papers and several reviews devoted to metathesis of silicon-containing compounds have been published over the last 40 years [153, 154, 162-166]. However, the number of scientific results on ROMP of monocycloolefins bearing silyl-containing substituents is limited due to complication of monomer syntheses. 

Below we demonstrate a few examples of ROMP of monocycloolefin Mes Si-derivatives. 

Mc3 Si-containing norbornenes and norbornadienes with two substituents in different positions also demonstrated high activity as monomers in ROMP (Table 4). 

The reports concluded that visual inspections of the K-Reactor tank have shown no unusual indications. The report also indicated that the operating. conditions do not adversely affect tank integrity and the material remains stable under normal load and credible accident conditions. These reports have been accepted by DOE however, recently WSRC reported that another report WSRC-RP-90-099, "Reactor Material Program-Leak Detection System Reliability" (Reference 15) will replace RP-SI-89-02. This item is a part of the ROMP DB-6.4, and has been reviewed and accepted in SER Section 6.7, System Integrity. 

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