A SMALL-ANGLE NEUTRON-SCATTERING STUDY OF THE PLASTIC-DEFORMATION OF LINEAR POLYETHYLENE

Small-angle neutron scattering (SANS) studies of a 5 vol% mixture of d euterated linear polyethylene with a protonated one was used to invest igate the role of partial melting-recrystallization during the solid-s tate deformation of the polymer in pure shear. The extension of previo us studies now gives data that cover the complete deformation range in a continuous manner. The quantity R(0), the ratio of the scattering a t zero angle for a given strain to that at zero strain, decreases very rapidly in the strain range 0-2. Here only modest changes occur in th e stress-strain curve. In the deformation region where the stress incr eases rapidly with strain, only a relatively small decrease occurs in R(0). The SANS results indicate that the major reorganization and homo genization occur at low strain. These results, coupled with the Flory- Yoon hypothesis of partial melting-recrystallization, explain the obse rvations that for a ductile-type deformation the ultimate properties d o not depend on the structural factors that define the initial undefor med state.