A convenient, highly-efficient method for preparation of hydroxyl-terminated isotactic poly(propylene) and functional di-block copolymer

Both terminated functional isotactic polypropylene (iPP) and block copolymers containing iPP segment are desirable for commercial applications. This paper provides a convenient, highly-efficient method to prepare hydroxyl-terminated isotactic polypropylene (iPP-t-OH) and functional di-block copolymer containing the iPP segment through a combination of coordination polymerization and coupling reaction. The coordination polymerization was catalyzed by TiCl4/MgCl2/AlEt3 catalyst system using ZnEt2 as chain transfer agent. Further, the Zn-terminated iPP was oxidized and subsequently hydrolyzed to provide iPP-t-OH. Soxhlet extraction and 13C NMR were used to calculate the isotacticity of iPP-t-OH. The degree of polymerization and the number of hydroxyl groups at the chain end of iPP-t-OH were measured by GPC and 1H NMR. Despite the high molecular weight and heterogeneous reaction, iPP-t-OH is effectively linked with PEG-t-NCO to produce di-block copolymers. DSC analysis of the di-block copolymer shows an obvious decrease in Tm and Tc, which indicated that PEG was successfully linked to the terminal end of iPP.

Graphical abstractHydroxyl-terminated isotactic polypropylene (iPP-t-OH) and functional di-block copolymer containing iPP segment were successfully prepared by a combination of coordination polymerization and coupling reaction.Figure optionsDownload full-size imageDownload as PowerPoint slide