Multi-armed polymers

Multi-armed polymers with a cyclotriphosphazene core XI and XII have been synthesized from the reaction of polyethylene glycol monomethyl ethers with acid chlorides of hexakis(3,5-dicarboxyphenoxy) and hexakis(4-carboxyphe-noxy) cyclotriphosphazenes. Their complexes with LiC104 were investigated, and their maximum conductivities are reported in Table 17 [621]. 

Linear star/ Multi - Armed Comb Polymers Networks (H y per) Bra n ched... 

The synthesis of various multi-arm star polymers has long been of growing practical and theoretical interest to a variety of industries. Star polymers have shown to be useful as surfactants, lubricants, rheology modifiers, and viscosity modifiers. Actually, star polymers are considered as viscosity modifiers and oil additives (15). 

Vasilenko NG, Rebrov EA, Muzafarov AM, EBweinB, StriegelB, MoUerM (1998) Preparation of multi-arm star polymers with polyMthiated carbosilane dendrimers. Macromol Chem Phys 199 889-895... 

Fig. 9 Schematic representation of (sections of) multi-arm star polymers in semidilute solution in good solvent. The three different length scales, the radius ofthe star R, the coat ri, hard core are indicated. The open circles denote the correlation length blob size)...

Yamamoto T (2003) Studies of long time relaxation of multi-arm star polymers. Ph.D Thesis. Kyoto University... 

Scheme 1.42. Multi-arm RAFT agents for the formation of star polymers. After Chong (1999).

The h rbranched polymer with bromine end groups was also used as a macroinitiator for the ATRP of n-butyl ac late. A multi-armed star polymer with a hypeibranched core was obtained wiUi, against linear polystyrene standards, M,=l 10,000 and NVMb=2.6. ... 

Li, Y. and Kissel, T., Synthesis characteristics and in vitro degradation of star-block copolymers consisting of Z-lactide, glycolide and branched multi-arm poly(ethylene oxide). Polymer, 39(18), 4421,1998. 

During polymerisation, linear as well as multi-armed copolymers are produced, as shown in Figure 3.10. During dispersion of the elastomer in the hot bitumen, the elastomer absorbs components from the bitumen (maltenes) and the polymer extends (swells) (Vonk and Van Gooswilligen 1989). 

The polymer-based miscible systems can be either intermolecular mixtures, for instance polymer solutions and blends, or intramolecular mixtures, such as block copolymers, star-shape multi-arm copolymers, grafted copolymers, random copolymers, and gradient copolymers with a composition gradient from one chain end to the other. Polymer-based miscible systems can phase separate into segregated phases with stable interfaces, or crystallize into crystalline ordered phases. In other words, there are two types of phase transitions, phase separation and crystallization. Under proper thermodynamic conditions, two phase transitions may occur simultaneously. The interplay of these two transitions will dictate the final morphology of the system. In the following, we will choose polymer solutions as typical examples to introduce the polymer-based miscible systems. 

Maier, S., et al. (2000). S5mthesis of poly(glycerol)-block-poly(methyl acrylate) multi-arm star polymers. Macromol. Rapid Commun., 21(5) 226-230. 

Figure 8.15 Synthesis of a PiBA-PS multiarm star block copolymers by the combination of RAFT-hetero-Diels-Alder and ATRP. (Reprinted from S. Sinn well, M. Lammens, M.H. Stenzel et al., Efficient access to multi-arm star block copolymers by a combination of ATRP and RAFT-HDA click chemistry, Journal of Polymer Science, Part A Polymer Chemistry, 47, 8, 2207-2213 (Figure 3), 2009, with the permission of John Wiley Sons, Inc.)...

Sinnwell, S., Lammens, M., Stenzel, M.H. et al. (2009) Efficient access to multi-arm star block copolymers by a combination of ATRP and RAFT-HDA click chemistry. Journal Polymer Science Part A-Polymer Chemistry, 47,2207. 

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