Synthesis of High Molecular Weight and End-Functionalized Poly(styrene oxide) by Living Ring-Opening Polymerization of Styrene Oxide Using the Alcohol/Phosphazene Base Initiating System

Abstract

The ring-opening polymerization (ROP) of styrene oxide (SO) was carried out using 3-phenyl-1-propanol (PPA) as the initiator and a phosphazene base, 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylidenamino]-2Λ5,4Λ5-catenadi(phosphazene) (t-Bu-P4), as the catalyst at room temperature. The polymerization proceeded in a living manner, which was confirmed by the kinetic and chain extension experiments, to produce the poly(styrene oxide) (PSO) with a controlled molecular weight (5200–21 800 g mol–1) and narrow molecular weight distribution (<1.14). The 1H NMR and MALDI-TOF MS measurements of the obtained PSO clearly indicated the presence of the PPA residue at the chain end. In addition, the t-Bu-P4-catalyzed ROP of SO with functional initiators, such as 4-vinylbenzyl alcohol, 5-hexen-1-ol, 6-azide-1-hexanol, and 3-hydroxymethyl-3-methyloxetane, successfully afforded the corresponding end-functionalized PSO with precise molecular control. The t-Bu-P4-catalyzed ROP of SO proceeded...