Block copolymerization anionic

By anionic block copolymerization of two monomers, thesecond being bi-unsaturated... 

Anionic block copolymerizations of MM A with lactones proceeded smoothly to give copolymers with Mw/Mn = 1.11-1.23 when the monomers were added in this order. However, when the order of addition was reversed, no copolymerization took place [3c], i.e., no addition of MMA to the polylactone active end group occurred (Scheme 12). 

The first method, which is used in many instances, proceeds by anionic block copolymerization. In a first step styrene is anionically polymerized using an efficient bifunctional initiator. The polymer obtained has a well-defined molecular weight, it exhibits a rather narrow molecular weight distribution and it has carbanionic living sites at both ends of its linear chains7. ... 

Star polymers having several PS branches and only one poly(2-vinyl naphthalene), PVN branch were prepared by Takano et al. using anionic polymerization techniques [31]. Sequential anionic block copolymerization of (4-vinyl-phenyl) dimethylvinylsilane (VS) and VN was employed. The double bonds attached to silicon have to remain unaffected during the polymerization of VS. This was ac-... 

A handicap of Grignard reagents in the field of anionic polymerization is certainly their low reactivity toward nonpolar double bonds. Unlike organolithium compounds, organomagnesium compounds are nornally inert toward monomers sueh as styrene or butadiene. Thus, their scope in the field of anionic block-copolymerization is quite limited. 

The anionic block copolymerization of methyl methacrylate and glycidyl methacrylate leads to very versatile surface-active agents. The hydrophilic/hydrophobic balance of these amphipatic macromolecules can be easily controlled not only by the relative length of the constitutive blocks but also by the chemical modification of the epoxy groups. The poly(glycidyl methacrylate) block can be easily sulfo-... 

Anionic block copolymerizations of MMA with lactones proceeded smoothly to give copolymers with Mw/Mn=1.11-1.23 when the monomers were added in this order (Fig. 13). 

Takano et al. employed anionic block copolymerization of a monomer with a reactive functional group and an ordinary monomer [256]. The requirement for this procedure is that the functional group has to be unreacted. This is accomplished using THF as a solvent and short reaction times. Since the multifunctional linking agent has been prepared, subsequent reaction with living chains produces miktoarm stars of the type AnB. In this study n = 13, A is PS, and B is poly-(vinylnaphthalene) (Scheme 88). 

Anionic block copolymerizations of MMA with lactones proceeded smoothly by... 

Synthesis of model Ideal styrene-DVB networks by anionic block copolymerization... 

Fig. 10 Integrated flow microreactor system for anionic block copolymerization of styrenes in THF. Ml, M2 micromixers Rl, R2 microtube reactors...

Controlled/Living Anionic Block Copolymerization of Styrenes and Alkyl Methacrylates Using Integrated Flow Microreactor Systems... 

Investigations were also made into surface nanostructures and their reconstruction behavior, by altering the outer environment using a series of block copolymers, namely PS-f)-poly(2-(perfluorooctyl)ethyl methacrylate) [96], PS-b-P(HEMA) [106, 107], and PS-f)-poly[(oligo(ethylene glycol) alkyl ether methacrylate), synthesized by anionic block copolymerization [116-120]. 

Previously, Hogen-Esch reported the successful synthesis of block copolymers composed of poly(acetylene) (PA) segments (PS-b-PA), by the living anionic block copolymerization of styrene and phenyl vinyl sulfoxide, followed by thermal treatment [158]. In this way, poly(phenyl vinyl sulfoxide) was completely converted to a PA segment A similar block copolymer was obtained by the reaction of chain-end-amine-fimctionaHzed poly(4-methylphenyl vinyl sulfoxide) with chain-end-COOH-functionaHzed PS via ionic interaction, followed by thermal treatment [215]. 

Anionic block copolymerization to prepare an in-chain-SiOMP-functionalized... 

Very few studies have been reported on the copolymerization of LA with 6-valerolactone (VL) and 3-butyrolactone (BL). Anionic block copolymerization of VL and LLA in the presence of potassium methoxide in THE at 20°C gave diblock copolymers with expected compositions and molecular weights [44]. Slight racemization of LLA was observed during polymerization due to transesterification reactions. 

Chloro-1,3-butadiene can be polymerized with styrene [528]. The anionic block copolymerization of 1- or 2-phenyl-1,3-butadiene with styrene leads to block polymers of low molecular weight [529]. Similar copolymers are described of 1,3-pentadiene with styrene. With alkyllithium there is no reaction of 1,4-diphenyl-1,3-butadiene with styrene [530]. 

The growing importance of thermoplastic elastomers is clearly evident from the papers presented at this Symposium. The majority of papers on elastomer synthesis deal with these types of block copolymers. The papers by Quirk and Tung describe the triblock copolymers based on -methylstyrene-butadiene and styrene-a-methylstyrene-diene systems, respectively. Anionic block copolymerization of hexamethyl- and hexaphenylcyclotrisiloxane is discussed in the paper (not included in this book) by Ibemesi, Gvozdic, Keumin, Lynch and Meier,... 

Ishizone, T. and Ito, M. (2002) Synthesis of well-defined poly(Al-isopropylacrylamide) by the anionic polymerization of Al-methoxymethy 1-Af-isopropylacrylamide. Journal of Polymer Science, Part A Polymer Chemistry, 40,4328-4332. Ishizone, T., Hirao, A., and Nakahama, S. (1993) Anionic polymerization of monomers containing functional groups. 6. Anionic block copolymerization of styrene derivatives para-substituted with electron-withdrawing groups. Macromolecules, 26,6964-6975. 

Ito, M. and Ishizone, T. (2004) Synthesis of well-defined block copolymers containing poly(N-isopropylacrylamide) segment by anionic block copolymerization of N-aietbo ymethyl-N-isopropylacrylamide. Designed Monomers and... 

Kloninger, C. and Rehahn, M. (2004a) 1,1-dimethylsilacyclobutane-mediated living anionic block copolymerization of [l]dimethylsilaferrocenophane and methyl methacrylate. Macromolecules, 37,1720. 

A precursory polystyrene-Z /6>c -poly(4-vinylphenol) is first prepared by living anionic block copolymerization of styrene and 4-t rt-butyldimethylsilyloxystyrene, followed by deprotection of the silyl group. The resulting polymer is reacted with 3-perfluorooctylpropyl bromide to afford the target polystyrene-Z /<9c -poly(4-(3-perfluorooctylpropoxy)styrene)... 

B. Star-Shaped Polymers by Anionic Block Copolymerization... 

Alternatively, the second step is achieved by anionic block copolymerization the carbonionic living sites at both ends of the precursor chains initiate the polymerization of a smalt amount of a bifunctional monomer (generally divinylbenzene). This polymerization yields small, tightly crosslinked nodules, each of which being connected with f chain ends. This method does not yield networks of known average functionality f. 

The PS network was synthetized by the end-linking procedure using the anionic block copolymerization of a mixture of linear PS (H) chains, containing 5% of perdeuterated chains of the same molecular weight, with divinylbenzene (three molecules per living end). The crosslinking reaction was performed in the presence of an aprotic solvent (equal volume of tetrahydrofuran and toluene), the overall polymer volume fraction being equal to 0.1. 

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