The self reinforcement of low density polyethylene (LDPE) in the oscillating stress field under low pressure was studied.With the orthogonal statistical analysis method

the optimum processing parameters have been found.The tensile strength of LDPE increased from 10 MPa of ordinary products to 21*!MPa of self reinforced specimen.The DSC and X-ray investigation indicates that the enhancement of tensile strength is due to the high degree orientation of macromolecule along flow direction and the crystalline refinery.The self-reinforced LDPE is more transparent than ordinary LDPE specimen due to crystalline refinery.The specimen breaks by tensile in a ductile manner

the toughness and elongation has not decreased with the increase of tensile strength.