Young's modulus of polyethylene in the microstrain region

The stress-strain behavior of various polyethylenes was measured with a str ain sensitivity of 2 X 10(-7). Young's modulus was measured as a function o f the strain rate. The shapes of the stress-strain curves in the vicinity o f room temperature were nonlinear down to the lowest measurable strain. The stress-strain behavior in the microstrain region was well described by the model of the standard linear solid. From the model, the relaxation time wa s determined along with the relaxed and unrelaxed moduli. (C) 2001 John Wil ey & Sons, Inc.