Structures and properties of blown moulding LLDPE films

Abstract

The crystalline structures, mechanical properties, transparence and fracture behaviours of linear low density polyethylene blown moulding films with nucleating agents incorporated in were investigated. The results indicated that with the nucleating agents used, the melting temperature Tm, crystalline structures, general profile of the stress–strain curves, tensile yield strength σy and essential work of fracture parameters before yield of the films, were almost unchanged, while the strain hardening phenomenon, tensile fracture strength σb, elongation at break &epsib, transparence and fracture parameters we and βwp were enhanced greatly. As the loading content of nucleating agent increasing, the crystallinity first decreased and then increased rapidly; the strain hardening phenomenon ϵb and σb increased to a maximum and then decrease to a stable value, while the Tm and σy were also unchanged; the haze decreased first and then reached a stable value; the we and we,y decreased remarkably first and then rapidly increased, even enormously exceeding the we of pure linear low density polyethylene, while βwp and βywp,y increased to a quite high value first and then dropped to a lower level.