Star polymer characterization

The second method is the most efficient way to synthesize well defined star polymers. It involves preparation of a living monocarbanionic precursor, which can be accurately characterized. In a second step, this polymer is reacted with a pluri-... 

Jacob S. and Kennedy J.P., Synthesis, characterization and properties of octa-arm polyisobytylene-based star polymers, Adv. Polym. Set, 146, 1, 1999. 

Jacob, S, and Kenned /. Synthesis, Characterization and Properties of OCTA-ARM Poly-isobutylene-Based Star Polymers. Vol 146, pp. 1-38. 

The molecular characterization of a polymeric material is a crucial step in elucidating the relationship between its properties (e.g., mechanical, thermal), its chemical structure, and its morphology. As a matter of fact, the development of a new product stems invariably from a good knowledge of the above relationships. Characterization of polymers is often a difficult task because polymers display a variety of architectures, including linear, cyclic, and branched chains, dendrimers, and star polymers with different numbers of arms. 

Further repeated intermolecular addition of the methacrylate ion onto the pendant methacrylate double bonds yields star-like polymers. Like the divinyl-benzene process in other anionic and in carbocationic living systems designed star polymers are difficult to obtain [78-80]. A recent detailed characterization of the PMMA stars has found that the number of arms typically varies between 10 and 100 and that each sample has a fairly wide distribution in the number of arms [78],... 

The core first method has been applied to prepare four-arm star PMMA. In this case selective degradation of the core allowed unambiguous proof of the star structure. However, the MWD is a little too large to claim that only four-arm star polymers are present [81], Comb PMMAs with randomly placed branches have been prepared by anionic copolymerization of MMA and monodisperse PMMA macromonomers [82], A thorough dilute solution characterization revealed monodisperse samples with 2 to 13 branches. A certain polydispersity of the number of branches has to be expected. This was not detected because the branch length was very short relative to the length of the backbone [83]. Recently, PMMA stars (with 6 and 12 arms) have been prepared from dendritic... 

The synthesis of well-defined LCB polymers have progressed considerably beyond the original star polymers prepared by anionic polymerization between 1970 and 1980. Characterization of these new polymers has often been limited to NMR and SEC analysis. The physical properties of these polymers in dilute solution and in the bulk merit attention, especially in the case of completely new architectures such as the dendritic polymers. Many other branched polymers have been prepared, e.g. rigid polymers like nylon [123], polyimide [124] poly(aspartite) [125] and branched poly(thiophene) [126], There seems to be ample room for further development via the use of dendrimers and hyperbran-... 

Synthesis, Characterization and Properties of Octa-Arm Polyisobutylene-Based Star Polymers... 

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