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:
Significant improvements in the fatigue life of polystyrene can be realized by increase in molecular weight. In this investigation, samples of polystyrene of varying molecular weight were subject to alternating cycles of axial tension and compression at a test speed of 1600 rpm. One set of fatigue tests was made on samples machined from commercial whole polymer rod. A second set of samples was prepared from a PS standard having an average molecular weight of 160,000 and a narrow molecular weight distribution. A third set of samples had a high average molecular weight of 860,000. For a whole polymer, the S-log N curves tended to have the same general shape as for metals, and the endurance limit appeared to be about 1400 psi. The test results show that the average fatigue life, at any given stress amplitude, is significantly increased by increase in molecular weight. For example, the average life of the high molecular weight standard at any given stress level was found to be more than tenfold that of the low molecular weight standard.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1972.070160220
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