Rheological properties of blown film low‐density polyethylene resins

Abstract Three blown‐film‐grade low‐density‐polyethylene (LDPE) resins were studied using different rheological techniques. Eccentric rotating disks (ERD), cone‐plate viscometry, capillary rheometry, annular die extrusion, and non‐isothermal stretching of a filament were used. The viscoelasticity of the melts was found to play a dominant role in the observed behavior. Extrudate appearance in annular flow, melt strength, and extensibility are affected by melt elasticity. A correlation was found between the maximum draw ratio of a filament stretched under non‐isothermal conditions and minimum film thickness.