Structures and properties of blown moulding LLDPE films

摘要

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 T_m, crystalline structures, general profile of the stress-strain curves, tensile yield strength σ_y and essential work of fracture parameters before yield of the films, were almost unchanged, while the strain hardening phenomenon, tensile fracture strength σ_b, elongation at break &epsi_b, transparence and fracture parameters w_e and βw_p were enhanced greatly. As the loading content of nucleating agent increasing, the crystallinity first decreased and then increased rapidly; the strain hardening phenomenon ε_b and σ_b increased to a maximum and then decrease to a stable value, while the T_m and σ_y were also unchanged; the haze decreased first and then reached a stable value; the w_e and w_e,y decreased remarkably first and then rapidly increased, even enormously exceeding the w_e of pure linear low density polyethylene, while βw_p and β_yw_p,y increased to a quite high value first and then dropped to a lower level.