Preparation and kinetic analysis of ps-b-pba block copolymer by 4-oxo-TEMPO capped Polystyrene macroinitiators
Journal
Journal of Applied Polymer Science
Journal Volume
113
Journal Issue
5
Pages
2833-2842
Date Issued
2009
Author(s)
Abstract
Abstract Polystyrene‐block‐poly( n ‐butyl acrylate) block copolymers were prepared from 4‐oxo‐2,2,6,6‐tetramethylpiperidinooxy (4‐oxo‐TEMPO) capped polystyrene macroinitiators at a high temperature, 165°C. It was found that the number‐average molecular weight of PBA chains in block copolymers could reach above 10,000 rapidly at early stage of polymerization with a narrow polydispersity index of 1.2–1.4, but after that, the polymerization seemed to be retarded. Furthermore, according to the kinetic analysis, the concentration of 4‐oxo‐TEMPO was increased mainly by the hydrogen transfer reaction of hydroxylamine (4‐oxo‐TEMPOH) to growing radicals during polymerization. This increase in 4‐oxo‐TEMPO concentration could retard the growth of polymer chains. The rate constant of the hydrogen transfer reaction of 4‐oxo‐TEMPOH to growing radicals, k H , estimated by the kinetic model is about 9.33 × 10 4 M ‐1 s −1 at 165°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Type
journal article