Poly comb shape

In several cases the melt viscosity of a series of lightly-branched polymers has been determined as a function of MW, and compared with that of linear polymers, and it has been found or may be deduced from the published data that there is a cross-over molecular weight, below which the branched polymer is less viscous, but above which it more viscous, than the linear polymer of equal MW. This behaviour is observed with some comb-shaped polystyrenes (35) and poly(vinyl acetate)s (59, 89), star polybutadienes (57, 58, 123), and randomly-branched polyethylenes (56,61). Jackson has found (141) that if the ratio ZJZC of the number of chain atoms at the cross-over point, Zx, to the number at the kink in the log 0 — logM curve, Zc, [as given in Ref. (52)], is plotted against nb, the number of branches, a reasonable straight line is obtained, as in Fig. 5.1. 

Benns, J.M., Choi, J.S., Mahato, R.I., Park, J.S. and Kim, S.W. (2000) pH-sensitive cationic polymer gene delivery vehicle V-Ac-poly(l- histidine)-graft-poly(l- lysine) comb shaped polymer. Bioconjug. Chem., 11, 637-645. 

The concept where amphiphihc molecules are hydrogen bonded to one block of a block copolymer to form specific comb-shaped supramolecules allows the production of nanoporous materials in a straightforward way. The concept is illustrated in Fig. 24. The procedure was first applied to a polystyrene-bZocfc-poly(4-vinylpyridine) diblock copolymer with a stoichiometric amount of pentadecylphenol hydrogen bonded to the P4VP block. The relative block lengths were selected to render a lamellar-m-cylindrical morphology, where the P4VP(PDP) comb-shaped blocks form the cylinders... 

The comb-shaped supramolecules discussed at length in this review allow a novel and general concept to prepare crew-cut aggregates as well as more complex shaped disklike objects. The procedure to prepare crew-cut nanoobjects is illustrated in Fig. 27 for the case of nanorods. The starting material is again poly(4-vinyl pyridinej-foZocfc-polystyrene. The corresponding comb-coil... 

Nakashima K, Maruyama T, Kamiya N, Goto M (2005) Comb-shaped poly(ethylene glycol)-modified subtilisin Carlsberg is soluble and highly active in ionic liquids. Chem Commun... 

Bo G, Wesslen B, Wesslen KB. Amphiphilic comb-shaped polymers from poly(ethylene glycol) macromonomers. J Polym Sci Part A Polym Chem 1992 30 1799-1808. 

Kurita, K., Amemiya, J., Mori, T., and Nishiyama, Y. 1999. Comb-shaped chitosan derivatives having oligo (ethylene glycol) side chains. Poly. Bull. 42, 387-393. 

Kodera,Y., Sekine, T., Yasokochi, T., Kiriu, Yoshihiro, Hiroto, Misao, Matsnshima, A., Inada, Y., Stabilization of L-Aspariginase modified with comb shaped poly(ethylene glycol) derivatives, in Vivo and in Vitro, Bioconjugate Chem., 1994 5 283-286. 

Benns JM, Choi JS, Mahato RI, Park JS, Kim SW. pH-sensi-tive cationic polymer gene delivery vehicle N-Ac-poly(L-histi-dine)-graft-poly(L-lysine) comb shaped polymer. Bioconjug Chem 2000 11 637-645. 

Xu, F.J. Ping, Y Ma, J. Tang, G.P. Yang, W.T. Li, J. Kang, E.T. Neoh, K.G. Comb-shaped copolymers composed of hydroxypropyl cellulose backbones and cationic poly((2-dimethyl amino) ethyl methacrylate) side chains for gene deHveiy. Bioconjug. Chem. 2009, 20 (8), 1449-1458. 

D.S. Kim, G.P. Robertson, M.D. Guiver, Comb-shaped poly(arylene ether sulfone)s as proton exchange membranes. Macromolecules 2008, 41(6), 2126-2134. 

Fig. 31 Supramolecular assembly of 2,4-bls(2-ethylhexylureido)toluene (EHUT) to form rigid structures and poly(isobutene) PIBUT) to form dynamic comb-shaped polymers. Reprinted with permission from [167]. Copyright 2010 American Chemical Society...

Xu FJ, Zhu Y, Liu FS, Nie J, Ma J, Yang WT (2010) Comb-shaped eraijugales comprising hydroxypropyl cellulose backbones and low-molecular-weight poly(JV-isopropylacryamide) side chains for smart hydrogels synthesis, characterization, and biomedical applications. Biocraijug Chem 21 456-464... 

In this entry, several kinds of comb-shaped polymers with highly ordered side chains have been introduced as attractive organic phases for RP-HPLC. Poly(octadecyl acrylate), ODA , is one of the simplest comb-shaped polymers, and its grafting for introduction onto silica surface is done by a one-step telomerization with 3-mercaptopropyl trimethoxysilane followed by immobilization with the terminal trimethoxysilyl group grafting-to method). The chromatographic results are summarized as follows ... 

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