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 dynamic mechanical properties at small strains have been determined for Hypalon-20 synthetic rubber, a commerical elastomer, by means of an electromagnetic transducer which is a modification of one described by Marvin, Fitzgerald, and Ferry. The measurements cover frequencies from 25 to 2500 cycles/sec. at twelve temperatures ranging from -8.4 to 68.4°C. Values of the real portion of the shear modulus (G′) vary from 7 × 106 to 2.1 × 109 dynes/cm.2, and those of the imaginary portion (G″) from 2.1 × 106 to 9 × 108 dynes/cm.2. The method of reduced variables (i.e., temperature-frequency superposition) is applicable and is used to extend G′ and G″ over the range 10-1 to 109 radians/sec. At 25°C., G″/G′ = 1.3 at its maximum at 105 radians/sec. The general function for the temperature dependence of mechanical properties proposed by Williams, Landel, and Ferry is valid up to 35°C. if one uses -24.5°C. for the glass transition temperature (Tg); dilatometrically Tg = -28 ± 1°C. The distribution function of relaxation times H(τ) has a pronounced maximum at about τ = 10-8 sec., decreases with a slope of about -0.57 (for log H versus log τ) to about τ = 10-3 sec., and is nearly flat from τ = 10-2 to 10 sec. H (τ) for Hypalon-20 is similar to those for polyisobutylene and polyhexene-1.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1959.070010204
Permalink
