Electron spin resonance study of the homopolymerization of aromatic bismaleimides

Hopewell J.L., Hill D.J.T. and Pomery P.J. (1998) Electron spin resonance study of the homopolymerization of aromatic bismaleimides. Polymer, 39 23: 5601-5607.

Author Hopewell J.L.
Hill D.J.T.
Pomery P.J.
Title Electron spin resonance study of the homopolymerization of aromatic bismaleimides
Journal name Polymer   Check publisher's open access policy
ISSN 0032-3861
Publication date 1998-01-01
Sub-type Article (original research)
Volume 39
Issue 23
Start page 5601
End page 5607
Total pages 7
Subject 1605 Policy and Administration
2507 Polymers and Plastics
Abstract Maleimide homopolymerization can be initiated by the maleimide monomer without the need for added initiator. This self-initiation is believed to occur through a donor-acceptor complex formed between maleimide groups. An in-situ electron spin resonance (e.s.r.) spectroscopic technique was used to study the free-radical homopolymerization of 1,1′-(methylenedi-4,1-phenylene)bismaleimide (MDP-BMI) over a range of temperatures. Total radical concentrations were measured as a function of time at polymerization temperatures from 180 to 230°C. By analysis of the e.s.r. spectra from different maleimide monomers, MDP-BMI, N-phenylmaleimide (NPM) and 1,1′-[methylenebis-(2,6-diethyl-4,1-phenylene)] bismaleimide (MDEP-BMI), with and without free-radical initiators, it was possible to identify the e.s.r. signals due to various radical species. Unreactive diphenylmethylene radicals were observed on the polymer chains formed from MDP-BMI. Additional spectral features are present that include the signal due to the propagating radical. Maleimides containing free-radical initiator also exhibited a broad doublet signal assigned to a vinyl radical formed by hydrogen abstraction from the maleimide double bond. From comparison of the spectra of NPM and MDEP-BMI monomers, both with and without free-radical initiators, it was shown that the maleimide propagating radical gives an unusually narrow, singlet e.s.r. peak quite different from the four-line signal previously reported.
Keyword Bismaleimides
E.s.r. spectroscopy
Free-radical polymerization
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
 
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Created: Tue, 12 Jul 2016, 11:04:21 EST by System User