Chemical and Biomolecular Engineering Faculty Research

Title

Effect of the Molecular Weight and Architecture on the Size and Glass Transition of Arborescent Polyisobutylenes

Document Type

Article

Publication Date

Spring 2006

Abstract

This article discusses the characterization of arborescent (hyperbranched) polyisobutylenes (arb-PIBs) by size exclusion chromatography and differential scanning calorimetry, in comparison with linear PIB standards. The radius of gyration (〈r〉1/2 = Rz), measured from the angle dependence of light scattering of high-molecular-weight arb-PIBs, was significantly larger than the hydrodynamic radius (Rh) from size exclusion chromatography/viscometry, and the Rh values were significantly smaller than Rh of linear PIBs. The glass-transition temperature of arb-PIBs having a branch molecular weight higher than the critical entanglement molecular weight was dependent on both the total number-average molecular weight and BR up to BR ∼ 15. A modified Fox–Flory equation is proposed to describe the effect of architecture on the thermal transition. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1770–1776, 2006

Publication Title

Journal of Polymer Science Part A: Polymer Chemistry

Volume

44

Issue

5

First Page

1770

Last Page

1776