Release Time:2019-03-12  Hits:

Indexed by: Journal Article

Date of Publication: 2018-06-28

Journal: POLYMER CHEMISTRY

Included Journals: SCIE

Volume: 9

Issue: 24

Page Number: 3347-3354

ISSN: 1759-9954

Abstract: This study demonstrates an efficient arm-first approach for the synthesis of star isotactic polypropylene (iPP) via two steps. In the first step iPP "arm" containing a methoxysilane-terminal end was prepared via a designed chain-capping reaction in propylene polymerization, and in the second step an acid-catalyzed intermolecular elimination reaction was carried out between methoxysilane groups at these "arm-ends", finally giving star polymers with iPP as the arm and Si-O-Si cross-linking structure as the core. Moreover, the arm number could be tailored from 3 to 8 by adjusting the star-forming (cross-linking) reaction time. The chemical structures of "arm" and star polymers were monitored by H-1-NMR, and the star-topological structure evolution was investigated via gel permeation chromatography incorporating a light scattering detector (GPC-LS). The star polymers' absolute molecular weights as well as their dilute solution properties including the intrinsic viscosity ([eta]) and the Mark-Houwink exponent (a) were determined by GPC-LS, confirming the successful synthesis of star iPPs.