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:
Studies on tensile strength of polybutadiene (BR) and ethylene-propylene diene rubber (EPDM) having a wide range of flaw sizes have been carried out under both normal and aging conditions. A similar study has been done for a solid propellant rocket insulator compound, based on EPDM. The morphology of tensile fracture surface has also been reported in each case in order to understand the mechanism of rupture. Unlike NR, EPDM, and BR gum vulcanizates, both unaged and aged, show no critical cut length (lc). lc may be defined as the cut length at which the strength decreases abruptly (sometimes there is a drop of a factor of 3 or more, at lc). However, the insulator compound, based on EPDM, exhibits a definite lc in the region of 1.5-1.7 mm. This arises because of anisotropic effect of asbestos fibers. Scanning electron microscopic studies show that the mechanisms of rupture of EPDM and BR gum vulcanizates are similar throughout the whole range of precuts. It occurs through a tearing process originated from the given precut at the center of the samples. A quantitative relation between tensile strength and distance between crack lines/tear lines has also been found. Though insulator compound shows a definite lc, similar fracture surface has been observed over the entire range of flaw sizes.
Additional Material:
27 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1988.070350205
Permalink
