ISSN:
0098-1273
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The spin-probe technique has been employed to study the nature of the surface regions of poly(trans-1,4-butadiene) crystals grown from dilute heptane and toluene solutions. The narrowing of the ESR spectrum of the nitroxide radical probe added to the PTBD crystals and the activation energy for the rotational motion of the probes were found to very with the crystallization solvent and annealing temperature; in every case heptane-grown crystals showed a higher line narrowing temperature and activation energy than toluene grown crystals. Annealing at 80°C raised the narrowing temperature and the activation energy for crystal preparations from both solvents used, but annealing at high temperatures, near to but below the melting point, lowered both parameters again. These results support earlier assertions, based on infrared spectra, surface epoxidation, differential scanning calorimetry, broad-line nuclear magnetic resonance, and dynamic mechanical results concerning the nature and location of the amorphous regions in PTBD crystals.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1976.180140207
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