ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Samples of plasticized poly(vinyl butyral-co-vinyl alcohol) (PVB) are found to exhibit multiple thermal transitions as observed by dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). Arrhenius plots using DSC and DMA data suggest that two of the transitions are glass-type ones. Variable temperature solid-state 13C-NMR experiments show a temperature-dependent line-broadening pattern for all PVB backbone carbons with maximum broadening at 55°C or at about 50°C above the second-order-type transitions α1 and α2 as measured by DSC. Using Arrhenius plots, the NMR transition is found to best correlate with α1, which is consistent with glass transition behavior. The solid-state NMR spectra also show that vinyl alcohol tacticity remains unresolved up to a temperature of about 95°C, beyond which line narrowing begins to occur. High-temperature thermal transitions are also observed by DSC and DMA, which suggest that the onset of motion involving vinyl alcohol sequences may be responsible for these transitions.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1992.070460210
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