scholarly journals Starting Spin-Label Technique

2010 ◽  
Vol 50 (1) ◽  
pp. 014-015
Author(s):  
Shun-Ichi OHNISHI
Keyword(s):  
Spin Label ◽  
Label Technique

Spin-Label Investigation of Polyurethane Networks

1974 ◽  
Vol 47 (5) ◽  
pp. 1160-1174
Author(s):  
T. C. Ward ◽  
J. T. Books
Keyword(s):  
Mechanical Properties ◽  
Spin Label ◽  
Amorphous Polymers ◽  
Diphenylmethane Diisocyanate ◽  
Label Technique ◽  
Spin Resonance ◽  
Soft Segments ◽  
Polyurethane Networks ◽  
Hard Block ◽  
Very High

Abstract Two types of polyurethane networks were examined using the spin-label technique. Nitroxide free radicals which are stable under moderate conditions were covalently attached to the network chains of amorphous polymers based on (1) poly(tetramethylene glycol), p,p′-diphenylmethane diisocyanate (MDI), trimethylolpropane, and (2) ethylene glycol, MDI, glycerine. Polymer (1) had very low “hard block” content, polymer (2) a very high content. Mechanical properties and differential thermal analysis measurements were made on polymer (1). Electron spin resonance spectra of the samples were obtained in the unstrained, strained, and swollen states. Large differences in the spectra were observed, depending on chemical composition, temperature, and state of swelling. Transitions from “frozen” to “rapid motion” type of spectra occurred at 70° for polymer (1), at −10° for polymer (1) swollen to equilibrium, and were unobserved up to 150° for polymer (2). Since the nitroxide label was necessarily adjacent to MDI units, was present in very small concentrations, and experienced no alterations in environment as “soft segments” did, then it is suggested that the spin-label technique is a valuable tool for analyzing microstructure of pseudoamorphous systems.

Segmental Dynamics and Self-Concentration around Chain Ends in Miscible Blend of Poly(cyclohexyl methacrylate) and Poly(cyclohexyl acrylate) As Studied by the Spin-Label Technique

2004 ◽  
Vol 37 (23) ◽  
pp. 8612-8617 ◽  
Author(s):  
Yohei Miwa ◽  
Takuya Tanabe ◽  
Katsuhiro Yamamoto ◽  
Yusuke Sugino ◽  
Masato Sakaguchi ◽  
...  
Keyword(s):  
Spin Label ◽  
Segmental Dynamics ◽  
Label Technique ◽  
Miscible Blend ◽  
Cyclohexyl Methacrylate
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