LONG-TIME CREEP IN A PURE-GUM RUBBER VULCANIZATE: INFLUENCE OF HUMIDITY AND ATMOSPHERIC OXYGEN.

Abstract

Long-time creep of natural rubber cured with a sulfur-accelerator recipe containing no filler can be conveniently represented by a plot of (E minus E//1)/E//1 equals DELTA E/E//1 with a double-abscissa scale showing log t and t. E is the elongation at any time t, after application of the load, and E//1 its value at unit time. Experimental data conform to the equation DELTA E/E//1 equals A log t plus B(t minus 1) except for a more rapid rise preceding rupture. The constants A and B can be evaluated from only three observations. The effect of ambient atmosphere and humidity on these constants is evaluated.