LDPE/EVA Modified Film Prepared by Melt Blend Method and Study of its Mechanical Performances and Barrier Property

Abstract

In this study, six kinds of different films from LDPE (Low-density polyethylene) modified by EVA (Ethylene - vinyl acetate copolymer) were made, and EVA / LDPE mass ratio was 0/50, 1/49, 1/ 19 4/21, and 1/3. Influence of EVA amount on the properties of LDPE film was investigated using the Instron universal testing machine, DSC, oxygen permeability tester and breathable apparatus. The mechanical properties of the blended films showed that when the EVA content was 5%, LDPE / EVA film transverse Young's modulus increased by about 50%, and the vertical Young's modulus increased by about 56%, which is good for improving the overprint accuracy of the LDPE / EVA film. DSC analysis showed that the melt blending has no effect on the thin-film processing temperature and thermal stability, but the result indicated that the crystallinity of the blended films was lowered with the increase of EVA amount. Barrier tests showed that with the increase of EVA content, the barrier of the modified films was decreased. The polarity of the film increased with more EVA component, which would augment the surface tension of LDPE and its ink adhesion.