| Abstract: | Viscoelastic nonlinearity was examined on uniaxially drawn films of high density and linear low density polyethylenes and their blends using dynamic ultrasonic measurements. It was found that nonlinearity due to plastic deformations, such as slippage and dislocations, occurs in the fibrous structures. Plastic deformations were different from those in corresponding undrawn films. For undrawn films, the formation and/or deformation of crystal defects and voids were caused by the disruption of spherulitic structures. Nonlinearity was smaller for drawn films than for undrawn films, suggesting that the superstructure of drawn films is more uniform and more stable for mechanical deformations. |
