Copolymer hyperbranched

Poly(arylene ether ketone)s (PEKs), 327 block and graft copolymers of, 359-361 hyperbranched, 349 modification of, 354 synthesis of, 340-345, 360 Poly(arylene ether phosphine oxide)s (PEPOs), 345... 

Puskas, J.E., Antony, P., Paulo, C., Kwon, J., Kovar, M., Norton, P., and Altstadt, V. Macromolecular engineering via carbocationic polymerization Branched and hyperbranched stmctures, block copolymers and nanostructures, Macromol. Mater. Eng., 286, 565-582, 2001. 

Nagy, A., Qrszagh, I., and Kennedy, J.P. Living carbocationic copolymerizations. II. Reactivity ratios and microstructures of isobutylene/p-methylstyrene copolymers, J. Phys. Org. Chem., 8, 273, 1995. Puskas, J.E. and Paulo, C. Synthesis and Characterization of Hyperbranched Polyisobutylenes. Proceedings of the World Polymer Congress (lUPAC Macro 2000), 384, 2000. 

Hyperbranched polymers have also been prepared via living anionic polymerization. The reaction of poly(4-methylstyrene)-fo-polystyrene lithium with a small amount of divinylbenzene, afforded a star-block copolymer with 4-methylstyrene units in the periphery [200]. The methyl groups were subsequently metalated with s-butyllithium/tetramethylethylenediamine. The produced anions initiated the polymerization of a-methylstyrene (Scheme 109). From the radius of gyration to hydrodynamic radius ratio (0.96-1.1) it was concluded that the second generation polymers behaved like soft spheres. 

However, the practical, direct synthesis of functionalized linear polyolefins via coordination copolymerization olefins with polar monomers (CH2 = CHX) remains a challenging and industrially important goal. In the mid-1990s Brookhart et al. [25, 27] reported that cationic (a-diimine)palladium complexes with weakly coordinating anions catalyze the copolymerization of ethylene with alkylacrylates to afford hyperbranched copolymers with the acrylate functions located almost exclusively at the chain ends, via a chain-walking mechanism that has been meticulously studied and elucidated by Brookhart and his collaborators at DuPont [25, 27], Indeed, this seminal work demonstrated for the first time that the insertion of acrylate monomers into certain late transition metal alkyl species is a surprisingly facile process. It spawned almost a decade of intense research by several groups to understand and advance this new science and to attempt to exploit it commercially [30-33, 61]. 

He and coworkers [368] synthesized a series of hyperbranched alternating copolymers of tetraphenyI (/)- b i phen yI)- met h a ne and -silane with 9,9-dihexylfluorene by Suzuki coupling... 

Hyperbranched copolymers, 7 610t, 654-655 Hyperbranched polyfchloromethyl styrene), 7 610t... 

Ishizu, K., Star polymers by immobilizing functional block copolymers, in (Mishra, N. K. and Kobayashi, S. (eds), Stars and Hyperbranched Polymers, Marcel Dekker, New York 1999. 

Structural variations of hyperbranched polyesters have also been achieved by copolymerizing an A2B-monomer with an AB-functional monomer, although no properties were reported for these copolymers [71]. 

Fig. 14. Hyperbranched polymer grafts prepared on a mercaptoundecanoic acid (MUA) self assembled monolayer confined to a gold substrate. PAAM-c-PAA represents a random copolymer of poly(acrylamide) and poly(acrylic acid) prepared from the poly(acrylic acid) carboxylic acid groups and an amine [129]...

Many micellar catalytic applications using low molecular weight amphiphiles have already been discussed in reviews and books and will not be the subject of this chapter [1]. We will rather focus on the use of different polymeric amphiphiles, that form micelles or micellar analogous structures and will summarize recent advances and new trends of using such systems for the catalytic synthesis of low molecular weight compounds and polymers, particularly in aqueous solution. The polymeric amphiphiles discussed herein are block copolymers, star-like polymers with a hyperbranched core, and polysoaps (Fig. 6.3). 

Fig. 6.3 Different types of micelles and micelle analogous structures a) amphiphilic block copolymers, b) star-like polymers with a hyperbranched core, c) polysoaps.

As an extension of the perspective of micelle formation by amphiphihc block copolymers the following part will focus on two other types of polymers. The micellar structures that will discussed are (i) micelles and inverse micelles based on a hyperbranched polymers and (ii) polysoaps, that are copolymers composed of hy-drophihc and amphiphihc or hydrophobic monomers. Whereas the first class of polymers is stiU very new and only few examples exist of the synthesis and appH-cation of such stracture in catalysis, the synthesis and aggregation characteristics of polysoaps has already been intensively discussed in the hterature. 

Starting from a hyperbranched polyester based on 4,4 -bis(hydroxyphenyl)valeric acid, terminal -OH groups were derivatized to yield the hyperbranched macroinitiator. The Hgand precursor was introduced as the first block in the grafting from reaction, followed by 2-methyl-2-oxazoHne polymerization to give the second block and allow for water-soluble polymers. The triphenylphosphine-functionalized am-phiphihc star block copolymer was obtained after transformation of the iodoaryl... 

Keywords. Dendrimers, Hyperbranched macromolecules. Block copolymers. Surface functionalization, Solvatochromism, Intrinsic viscosity... 

We are currently initiating three research projects that include (1) the synthesis of reflective liquid crystal/polymer composite films, (2) a study of microphase separation in hyperbranched block copolymers, and (3) the design and synthesis of polar organic thin films, which is the subject of this proposal. (47 words aim for 41 words)... 

A number of different types of copolymers are possible with ATRP—statistical (random), gradient, block, and graft copolymers [Matyjaszewski, 2001]. Other polymer architectures are also possible—hyperbranched, star, and brush polymers, and functionalized polymers. Statistical and gradient copolymers are discussed in Chap. 6. Functionalized polymers are discussed in Sec. 3-16b. 

Statistical, gradient, and block copolymers as well as other polymer architectures (graft, star, comb, hyperbranched) can be synthesized by NMP following the approaches described for ATRP (Secs. 3-15b-4, 3-15b-5) [Hawker et al., 2001]. Block copolymers can be synthesized via NMP using the one-pot sequential or isolated macromonomer methods. The order of addition of monomer is often important, such as styrene first for styrene-isoprene, acrylate first for acrylate-styrene and acrylate-isoprene [Benoit et al., 2000a,b Tang et al., 2003]. Different methods are available to produce block copolymers in which the two blocks are formed by different polymerization mechanisms ... 

The formation of synthetic polymers is a process which occurs via chemical connection of many hundreds up to many thousands of monomer molecules. As a result, macromolecular chains are formed. They are, in general, linear, but can be branched, hyperbranched, or crosslinked as well. However, depending on the number of different monomers and how they are connected, homo- or one of the various kinds of copolymers can result. The chemical process of chain formation may be subdivided roughly into two classes, depending on whether it proceeds as a chain-growth or as a step-growth reaction. 

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