Synthesis and Coupling of ABx Polysiloxane Macromonomers to Form Highly Branched Polysiloxanes

Yolsal, Utku; Hutchings, Lian R.

Abstract

This work focuses on the synthesis of polysiloxane ABx macromonomers with functional groups (A [Si-H] and B [vinyl]) incorporated on to the polymer backbone, and the coupling of these functionalities to form randomly, but highly, branched polymers. The synthesis of the ABx macromonomers was performed by the anionic copolymerization of hexamethylcyclotrisiloxane (D3) and 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane (V3) monomers, followed by an end-capping/termination reaction with chloro(methyl)phenylsilane. The resulting macromonomers were coupled by a Pt(0) catalyzed hydrosilylation reaction, to yield highly branched polysiloxanes. The coupling reaction was investigated at different solution concentrations and using macromonomers with different extents of vinyl content. It was shown that a higher solution concentration resulted in higher degrees of chain coupling and branching, arising from efficient intermolecular coupling in preference to (the competing) intramolecular coupling (cyclization) reaction. Moreover, an increase in the mole fraction of vinyl monomer also resulted in higher levels of branching. With the ability to control the degree of branching, the strategy reported here provides a facile route to synthesize branched polysiloxanes (silicones) with varying flexibility and elasticity

Citation

Yolsal, U., & Hutchings, L. R. (2019). Synthesis and Coupling of ABx Polysiloxane Macromonomers to Form Highly Branched Polysiloxanes. European Polymer Journal, 113, 254-259. https://doi.org/10.1016/j.eurpolymj.2019.01.066

• Journal Article Type: Article
• Acceptance Date: Jan 30, 2019
• Online Publication Date: Jan 31, 2019
• Publication Date: Apr 30, 2019
• Deposit Date: Feb 1, 2019
• Publicly Available Date: Jan 31, 2020
• Journal: European Polymer Journal
• Print ISSN: 0014-3057
• Electronic ISSN: 1873-1945
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 113
• Pages: 254-259
• DOI: https://doi.org/10.1016/j.eurpolymj.2019.01.066
• Public URL: https://durham-repository.worktribe.com/output/1303984