Star-shaped polymers poly

More recent examples include end-functionalized multiarmed poly(vinyl ether) (44), MVE/styrene block copolymers (45), and star-shaped polymers (46—48). With this remarkable control over polymer architecture, the growth of future commercial appHcations seems entirely likely. 

Copolymerization of TMC with e-CL or L-lactide has been reported to be useful for modifications of the polymer properties [144,218,280,283]. The molecular architecture presents a powerful tool for obtaining new materials with interesting properties. For instance, a star-shaped rubbery poly(TMC-co-CL) was synthesized. d,L-LA/GA polymerization was then initiated from the hydroxy terminated arms to yield a poly(TMC-co-CL)-block-PLGA [284]. 

The core-first method, which uses an active multifimctional core to initiate growth of polymer chains, was apphcable to make hybrid POSS-core star-shaped polyoxazohnes that showed an increase in Tg, compared to that of polyoxazohne initiated by methyl p-toluenesulfonate (MeOTs) with poly(2-methyl-2-oxazohne) (POZO) [76]. Other hybrid star-shaped polyoxazohnes initiated by cube-OTs or cube-benzyl revealed the same phenomenon. This was attributed to the reduction of segmental mobifity of POZO in starshaped polyoxazolines, which was caused by the incorporation of hard, compact POSS moiety to the core of star polymer with the core-first technique. The conclusions were drawn that the thermal stabilities of star-shaped polymers increased as the POSS wt % was increased, and this was used as a measure of the effect of the inorganic POSS unit on polymer thermal properties. 

Wodzki R, Swiatkowski M, and Lapienis G. Properties of star-shaped polymer with poly(oxyethylene) branches and monoesters of phosphoric acid end groups in pertaction of alkali, alkaline earth, and transient metal cations. React Funct Polym, 2002 52(3) 9-161. 

Unlike previous researchers, Xue and Agarwal were more interested in the effect of core structure on the shear stability of star-shaped polymers. They synthesized six-arm star poly(methyl methacrylate) (PMMA) bearing either a linear core (A, M = 2,350 kDa) or a fused core (B, M = 2,100 kDa) (Fig. 31) [228,... 

H. Gao, M. C. Jones, P. Tewari, M. Ranger and J. C. Leroux, Star-shaped alkylated poly(glycerol methacrylate) reverse micelles synthesis and evaluation of their solubilizing properties in dichloromethane. /. Polym. Sci. Polym. Chem., 45, 2425-2435 (2007). 

Figure 8.12 The SEC analysis of the PiBA star-shaped polymer, P(EtOx)2o and the coupling product before (bottom) and after preparative SEC (top) (Lammens et al, 2009). (Reprinted from M. Lammens, D. Fournier, M.W.M. Fijten et aL, Star-shaped poly acrylates Highly functionalized architectures via CuAAC click conjugation, Macromolecular Rapid Communications, 30, 23, 2049-2055 (Table 2, Figure 3), 2009, with the permission of John Wiley Sons, Inc.)...

Star-shaped poly(IBVE) was obtained in 100% yield [276] from the living polymer reaction (DPn = 50-300) of IBVE, prepared with IBEA/EtAlCl2 at 0 C in hexane in the presence of ethyl acetate, with a small amount of 1,4-cyclohexanedimethanol divinyl ether. A notable feature of these starshaped polymers was their extremely narrow MWDs (Mw/Mn = 1.1-1.2) [276]. To the best of our knowledge, this was the first example of selective preparation of star-shaped polymers with a narrow MWD in quantitative yield, which had never before been achieved even with other polymerization mechanisms. The Mw ranged from 6 x 10" to 30 x 10, and each polymer molecule had between 9 and 44 arms. 

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