Issue 2, 2023

Synthesis of guanidinophosphazene superbase for the facile preparation of high molecular weight polysiloxane under mild conditions

Abstract

In one step, two bulk chemicals of hexachlorotriphosphonitrile and 1,1,3,3-tetramethylguanidine were selected to prepare a guanidinophosphazene superbase 2,2,4,4,6,6-hexa(tetramethyl-guanidyl)-1,3,5,2λ5,4λ5,6λ5-cyclictri(phosphazene) (HTGCP, pKa of 27.2 in MeCN). The obtained HTGCP exhibits extremely high catalytic performance toward hexamethylcyclotrisiloxane (D3) in toluene and the conversion can exceed 99% under mild conditions within 10–60 min (molecular weight Mn = 10–836 kg mol−1). At high monomer dosage, Mn can be increased to 1136 kg mol−1 at 120 min. The structure and Mn of the resulting polymer have been confirmed by GPC, 1H NMR, 29Si NMR, and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MS). The ionic reaction between initiator and HTGCP ensures polymerization in the form of first-order reaction kinetics. Meanwhile, the polymerization rate constant increases remarkably with the increase in HTGCP concentration and the excellent linear relationship between Mn and [M]/[I] indicates well-controllable polymerization for D3. In addition, the HTGCP can still obtain high Mn for the polymerization of octamethylcyclotetrasiloxane (D4) and tetramethyl tetravinyl cyclopentasiloxane (V4), while the molecular weight distribution is relatively broad. As a superbase, HTGCP has a simpler preparation method and exhibits good application in organic polymerization under mild conditions.

Graphical abstract: Synthesis of guanidinophosphazene superbase for the facile preparation of high molecular weight polysiloxane under mild conditions

Supplementary files

Article information

Article type
Paper
Submitted
11 Oct 2022
Accepted
08 Nov 2022
First published
18 Nov 2022

Polym. Chem., 2023,14, 172-182

Synthesis of guanidinophosphazene superbase for the facile preparation of high molecular weight polysiloxane under mild conditions

W. Duan, Z. Li, Z. Yang, F. He, S. Chen, C. Qiao, J. Yao, C. Zhang, H. Zhao, M. Li and G. Yang, Polym. Chem., 2023, 14, 172 DOI: 10.1039/D2PY01294D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements