Branched and Functionalized Polybutadienes by a Facile Two-Step Synthesis

✍ Scribed by Frederik Wurm; Francisco-J. López-Villanueva; Holger Frey

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 241 KB
• Volume: 209
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.200700574

✦ Synopsis

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 AB~2~ + A type “pseudocopolymerization” method. All branched polymers were analyzed by SEC, SEC‐MALLS, SEC‐viscosimetry. ^1^H 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 AB~2~ monomers. Detailed kinetic studies showed that the polymerization occurred very rapidly in comparison to the hydrosilylation polymerization of classical AB~2~ type carbosilane monomers.

magnified image