ISSN:
0032-3888
Keywords:
Chemistry
;
Chemical Engineering
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:
The temperature dependence of the Newtonian viscosity, ηo(T), of four structurally related amorphous thermoplastics (polyarylate, polysulfone, polycarbonate, and phenoxy) was measured in the temperature region between Tg and (Tg + 100 K) by means of a parallel plate technique. This offers a simple and quick alternate mode of measurement to traditional techniques. Values of ηo(T) measured, as well as some data obtained from literature and corresponding to the T 〉 (Tg + 100 K) range, were fitted to Vogel-Fulcher expressions. Fractional free volume at Tg was evaluated from Vogel-Fulcher parameters. The values obtained are similar for all polymers studied, and they are greater than those normally observed for other amorphous polymeric systems that are structurally simpler. From the results obtained we can conclude that the rheological behavior and, hence, the chain “stiffness” of polyarylate, polysulfone, and polycarbonate, at the temperature range of industrial processing, are very similar. However, phenoxy, which contains a greater number of nonaromatic flexible structures in its chain, has a different behavior with a lower activation energy for viscous flow in the same range of temperature.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pen.760271107
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