ISSN:
1435-1536
Keywords:
Light scattering
;
high pressure
;
α-relaxation
;
β-relaxation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Photon correlation spectroscopy has been used to study relaxation processes in bulk polymers: PEA and PEMA, above the glass transition temperature under high pressure. In the case of PEA one relaxation process was observed over the whole pressure range of 1–2000 bar. This process is assigned to the localized backbone motion of the polymer chain. In PEMA two overlaping relaxation modes have been found. Quantitative characterization of these two modes was possible after their separation in the time domain, which was achieved by applying high pressure to the sample. It was found that an additionalα-methyl group in PEMA (in comparison with PEA) causes an appearance of an additional relaxation mode which can be assigned to the side group motion. Moreover, the localized backbone motion in PEMA is more cooperative because of a hindrance effect due to the presence of the additionalα-methyl side group. The obtained results are in a good agreement with the previous dielectric relaxations studies.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01413129
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