Effect of blending small amount of high-density polyethylene on molecular entanglements during melt-drawing of ultrahigh-molecular-weight polyethylene

The effect of blending a small amount of high-density polyethylene (HDPE) on molecular entanglements during melt-drawing of ultrahigh-molecular-weight polyethylene (UHMW-PE) was investigated in this study. UHMW-PE powders with a small amount of HDPE added and a bimodal MW distribution were synthesized by reactor blending. In situ wide-angle X-ray diffraction and small-angle X-ray scattering measurements during melt-drawing of UHMW-PE and UHMW-PE/HDPE films were performed to evaluate the state of molecular entanglements on the basis of the behavior of oriented crystallization and extended-chain crystal formation. The addition of a small amount of HDPE reduced the amount of tight molecular entanglements originating from UHMW-PE chains, and further addition reduced the amount of molecular entanglements that transmitted the applied stress. These results demonstrated that the addition of a small amount of HDPE significantly affected the amount of molecular entanglements of UHMW-PE chains during melt-drawing. • We clarified the effect of HDPE on molecular entanglements of UHMW-PE chains. • UHMW-PE/HDPE reactor blended powders with bimodal MW distributions were synthesized using a metallocene catalyst system. • In situ WAXD and SAXS measurements during melt-drawing were performed. • The addition of a small amount of HDPE reduced the amount of tight molecular entanglements originating from UHMW-PE chains. • Further HDPE addition reduced the amount of molecular entanglements that transmit the applied stress.