Multiarm Star Polyisobutylenes

Synthesis, Characterization, and Properties of Stars Consisting of Many Polyisobutylene Arms Radiating from a Core of Condensed Cyclosiloxanes

“…1 During these investigations we have also observed that in the presence of traces of water in the hydrosilation charges a certain quantity of stars with a much higher number of arms than the expected 6 also arose. 1 The formation of these "higher order" stars was explained by corecore coupling, [2][3][4] a process which was corroborated by direct experiments. 1 Since the number of common methylcyclosiloxanes with multiple SiH functions is quite limited (only two such cyclosiloxanes are commercially available, D 4 H and D 5 H ), the preparation of the target multiarm stars by hydrosilation of PIB-allyl by a specific methylcyclosiloxane appeared to be cumbersome.…”

“…19 The products were characterized by 1 H-NMR spectroscopy (200 MHz for PIB-methallyl and 600 MHz fo PIB-allyl) and GPC, details of which have been described. 1,20 Procedures. (a) PIB Prearms and Calculation of Number of Arms of Stars.…”

“…1 Since the number of common methylcyclosiloxanes with multiple SiH functions is quite limited (only two such cyclosiloxanes are commercially available, D 4 H and D 5 H ), the preparation of the target multiarm stars by hydrosilation of PIB-allyl by a specific methylcyclosiloxane appeared to be cumbersome. Also, we have found 1 that steric compression severely limits the quantitative hydrosilation of multiple neighboring SiH groups.…”

Cationic Polymerization Astronomy. Synthesis of Polymer Stars by Cationic Means

“…For example, a series of stars with polytetrahydrofuran arms have been assembled by quenching living THF polymerization by NH 3 47 (or amines) which in this case functions as a tetrafunctional linking agent (see Table 1). Multifunctional sodiomalonates, 43 silyl vinyl ethers, 13,44 and cyclic siloxanes containing Si-H groups [48][49][50][51] have also been used as linking agents.…”

Organic/Inorganic Nanocomposite Star Polymers via Atom Transfer Radical Polymerization of Methyl Methacrylate Using Octafunctional Silsesquioxane Cores

“…[43][44][45] The use of octahydridosilsesquioxane 46 (T 8 H ) as the core for the synthesis of star poly(isobutylene) (PBI) using the "arm-first" method has also been reported. Here, allyl-terminated PBI chains were reacted where coupled to the Si-H groups via hydrosilylation.…”