Orientation characteristics of LLDPE blown films and their implications on Elmendorf tear performance

The orientation features of several linear low-density polyethylene (LLDPE) blown films were characterized and significant insights into the morphological origin of Elmendorf tear resistance were developed. The orientation features of all the LLDPE blown films investigated were described in terms of the Keller-Machin "row" structure. The machine direction (MD) tear resistance was observed to be higher when the non-crystalline chains were closer to equi-biaxial in the plane of the film. Further, the transverse direction (TD) tear resistance was observed to he high when the crystalline lamellae were minimally curved and oriented closer to the film TD. These results indicated that deformations in the interlamellar region and the stresses borne along the lamellar long axes play important roles in distinguishing the MD and TD tear resistances, respectively, of LLDPE blown films. (C) 2000 Elsevier Science Ltd. All rights reserved.