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:
The design, construction, and operation of a unit for measuring linear expansion properties of polymers is described. This unit utilizes a proximity transducer capacitance gauge to measure variations in capacitance caused by expansion of a sample of polymer held in an Invar (low expansion alloy) sample holder. Measurement of displacement and of temperature is continuously recorded on an X-Y recorder. The effect of operating conditions on the measurement of the linear expansion is described, and certain experimental artifacts are shown. In addition, the application of the instrument to polypropylene, styrene-butadiene rubber, butyl rubber, and to ethylenepropylene rubber is described. Distinct, nonliner regions were found, above the normal glass transition temperatures, for butyl rubber and for ethylene-propylene rubber. In the former case, the effect is probably due to crystallinity; in the latter case, there are probably two minor transitions at about -35°C. and at about -5°C. in addition to the major transition at -67°C. These minor transitions may be due to atactic and to stereoblock propylene segments, respectively.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1964.070080422
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