Effects of melt-extension and annealing on row-nucleated lamellar crystalline structure of HDPE films

The row-nucleated lamellar crystalline structure of high-density polyethylene (HDPE) films was prepared by applying elongation stress to HDPE melt during T-die cast film extrusion and subsequently annealing the extruded films. This unusual crystalline structure was analyzed in terms of lamellar crystalline orientation, long-period lamellar spacing, crystallite size, and degree of crystallinity. The contribution of melt-extension represented by draw-down-ratio (DDR) to the overall orientation was found to be most noticeable than other processing variables. Meanwhile, the long-period lamellar spacing, the crystallite size, and the degree of crystallinity were influenced predominantly by the annealing temperature. Finally, the processing (melt extension and annealing temperature) structure (lamellar crystalline structure) - property (hard elasticity) relationship of HDPE films was investigated.