Star, multi-armed

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

In 1965, Milkovich (. ) reported that divinylbenzene could be utilized for the formation of star-branched macromolecules. Later, Rempp and coworkers (2, 3, 4) successfully applied this method for the synthesis of star-branched polystyrenes. Moreover, Fetters and coworkers (54 ) used this procedure for the synthesis of multi-arm star-branched polyisoprene homopolymers and poly-... 

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. 

Marsalko TM, Majoros I, Kennedy JP (1997) Multi-arm star polyisobutylenes. V. Characterization of multi-arm polyisobutylene stars by viscometry, pour points, electron microscopy, and ultrasonic shear degradation. J Macromol Sci A 34 775-792... 

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. 

Figure 5.36 Left, sketch of the HBPO-star-PEO multi-arm copolymer. Blue, HBPO core red, PEO arms. Right, optical micro-spectrometry images of a penta-walled self-assembled tube in acetone (scale bar. 300 pm). S...

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