Plastic deformation of polyethylene by rolling and drawing

High density polyethylene film in a wide temperature range may be easily drawn by neck propagation to draw ratios between 7 and 30. Lower draw ratios between 1 and 10 may be obtained by rolling. The two types of plastic deformation differ to some extent in crystal lattice and lamella orientation but are rather similar as far as long period and the number of tie molecules are concerned. At large draw ratio the long period depends nearly uniquely on the temperature of drawing or rolling and is independent of the long period of the starting material. At low draw ratio the opposite is true. The number of tie molecules increases with the draw ratio and finally reaches a limiting value, but does not depend on the temperature of drawing or rolling in the temperature range investigated. The longitudinal elastic modulus and tensile strength of the samples seem to be roughly proportional to the number of tie molecules.