Poly structures prepared

Nakase, Kurijama, I. and Odajima, A. Analysis of the Fine Structure of Poly(Oxymethylene) Prepared by Radiation-Induced Polymerization in the Solid State. Vol. 65, pp. 79-134. 

We have reported the first example of a ring-opening metathesis polymerization in C02 [144,145]. In this work, bicyclo[2.2.1]hept-2-ene (norbornene) was polymerized in C02 and C02/methanol mixtures using a Ru(H20)6(tos)2 initiator (see Scheme 6). These reactions were carried out at 65 °C and pressure was varied from 60 to 345 bar they resulted in poly(norbornene) with similar conversions and molecular weights as those obtained in other solvent systems. JH NMR spectroscopy of the poly(norbornene) showed that the product from a polymerization in pure methanol had the same structure as the product from the polymerization in pure C02. More interestingly, it was shown that the cis/trans ratio of the polymer microstructure can be controlled by the addition of a methanol cosolvent to the polymerization medium (see Fig. 12). The poly(norbornene) prepared in pure methanol or in methanol/C02 mixtures had a very high trans-vinylene content, while the polymer prepared in pure C02 had very high ds-vinylene content. These results can be explained by the solvent effects on relative populations of the two different possible metal... 

Over the past decade, literally dozens of new AB2-type monomers have been reported leading to an enormously diverse array of hyperbranched structures. Some general types include poly(phenylenes) obtained by Suzuki-coupling [54, 55], poly(phenylacetylenes prepared by Heck-reaction [58], polycarbosilanes, polycarbosiloxanes [59], and polysiloxysilanes by hydrosilylation [60], poly(ether ketones) by nucleophilic aromatic substitution [61] and polyesters [62] or polyethers by polycondensations [63] or by ring opening [64]. 

Characterization of the poly(macromonomers) prepared by homopolymerization has proved that they provide a useful probe for discussing the structural characteristics of the star and brush polymers. Graft copolymers have been and will be a most important area of application of the macromonomer technique since a variety of multi-phased and microphase-separated systems can easily be designed just by an appropriate combination of a macromonomer and a conventional monomer. In general, however, characterization of their absolute MW, branch/backbone composition as well as their distributions remain to be studied in more detail. 

A combination of other polymerization pathways also results in some hyperbranched structures. Multifunctional hydroxyl groups in polyglycerol with hyperbranched structure, prepared by anionic polymerization of glycidol, were esterified with 2-bro-moisobutyroyl bromide and then employed as a hyperbranched multifunctional macroinitiator for the copper-catalyzed radical polymerization of MA to give products with 45—55 poly(MA) arms.449... 

In the cyclopolymerization of methacrylic anhydride(MA) as a typical 1,6-diene, five- and six-membered ring anhydride structures can be formed, respectively corresponding to intramolecular hh and ht addition of uncyclized radical. The IR spectrum of poly-MA has been tentatively compared earlier with that of poly-MA prepared by dehydration of poly(methacrylic acid)(37) no five-membered cyclized anhydrides were detected, any absorption at higher frequency due to the strain of a five-membered ring being absent. 

Preparation of RubCon compositions in view of poly structure principles assumes application of separate technology. 

Stereospecific polymerization catalysts. The poly(phenylacetylene) prepared with Ziegler catalyst 28 possesses mainly the cis-cisoidal structure (as evidenced by the C—H out-of-plane deformation at 740 cm" in the IR spectrum), and is insoluble in all solvents owing to its high crystallinity. Rhodium catalysts such as 29 and 30 provide a soluble, cis-transoidal poly(phenylacetylene) . This polymer exhibits a sharp peak due to the olefinic proton at b 5.8 in the NMR spectrum. 

Figure 5.2. Chemical structure and synthetic route of acrylate-based azo poly-mers prepared from the PAC precursor.

Analyst of the Fine Structure of Poly(Oxymethylrae) Prepared by Radiation-Induced Polymerization in the Solid State... 

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