Branched and Functionalized Polybutadienes by a Facile Two‐Step Synthesis

Abstract

Anionic polymerization was used to prepare silane‐endfunctionalized polybutadiene macromonomers with different molecular weights ranging from 9 000 to 34 000 g · mol−1. These were polymerized by a hydrosilylation reaction in bulk to obtain branched polymers, using Karstedt's catalyst. Surprisingly, the addition of monofunctional silanes during the polymerization showed only a minimal effect concerning the degree of polymerization. Furthermore, it was possible to introduce a variety of functional silanes without increasing the overall number of reaction steps by a convenient AB2 + A type “pseudocopolymerization” method. All branched polymers were analyzed by SEC, SEC‐MALLS, SEC‐viscosimetry. 1H NMR spectroscopy, and DSC concerning their branching ratio. The branching parameters for the branched polymers exhibited similar characteristics as for hyperbranched polymers obtained from conventional AB2 monomers. Detailed kinetic studies showed that the polymerization occurred very rapidly in comparison to the hydrosilylation polymerization of classical AB2 type carbosilane monomers.magnified image

A followup study of antiphospholipid antibodies and associated neuropsychiatric manifestations in 137 children with systemic lupus erythematosus

“…These AB n ‐type macromonomers were applied in a concurrent copolymerization with 1 using Karstedt's catalyst (Scheme ) as the hydrosilylation catalyst. In contrast to the functionalization reactions with other silanes reported earlier,11 the viscosity of the polymerization mixtures increased rapidly in the presence of ferrocenylsilanes 1 and 2 . Thus, the reaction mixture had to be diluted with toluene to ensure homogeneous reaction conditions for complete conversion.…”

“…In an elegant work, Hutchings et al9 recently presented the synthesis of branched polymers from α,ω‐functional AB 2 ‐type polystyrenes to polydisperse “Hypermacs” and well‐defined “Dendrimacs.” More recently, we have reported an approach that relies on a convenient polyaddition of AB n ‐type macromonomers, leading to irregularly branched polyisoprenes10 and polybutadienes 11. Both types of macromonomers were prepared via classical anionic polymerization and endcapped with chlorodimethylsilane, directly leading to an AB n ‐type macromonomer for an ensuing hydrosilylation.…”

Long‐Chain Hyperbranched Polymers: Synthesis, Properties, and Applications

“…The rheological study is always used to examine the HBP architectures and topologies, and also provides some idea for estimating DB values, as usually adopted in some of the above‐noted references . The information concerning polymer chain entanglements are usually obtained from rheological measurements.…”

Chain Architecture as an Orthogonal Parameter To Influence Block Copolymer Morphology. Synthesis and Characterization of Hyperbranched Block Copolymers: HyperBlocks

“…The temperature was thus decreased to 40°C. It can be seen from Table 2 needed to generate the Cu(I) 67 . These two compounds were added in few drops of water which corresponded to ca.…”