Oxygen permeability and the mechanical and thermal properties of (low-density polyethylene)/poly (ethylene-co-vinyl acetate)/organoclay blown film nanocomposites

Various (low-density polyethylene)/poly(ethylene-co-vinyl acetate) (LDPE/EVA) nanocomposites containing organoclay were prepared by one- and two-step procedures through melt blending. The resultant nanocomposites were then processed via the film blowing method. From the morphological point of view, X-ray diffraction and optical microscopy studies revealed that although a prevalent intercalated morphology was evident in the absence of EVA, a remarkable increase of organoclay interlayer spacing occurred in the EVA-containing systems. The advantages of the addition of EVA to the LDPE/organoclay nanocomposites were confirmed in terms of oxygen barrier properties. In other words, the oxygen transmission rates of the LDPE/EVA/organoclay systems were significantly lower than that of the LDPE/organoclay sample. The LDPE/EVA/organoclay films had better mechanical properties than their counterparts lacking the EVA, a result which could be attributed to the improvement of the organoclay reinforcement efficiency in the presence of EVA. Differential scanning calorimetry and thermogravimetric analysis experiments were performed to follow the effects of the EVA and/or organoclay on the thermal properties of LDPE. Finally, the films produced from the two-step-procedure compound showed enhanced oxygen barrier properties and mechanical behavior as compared to the properties of the films produced via the one-step procedure. J. VINYL ADDIT. TECHNOL., 19:132139, 2013. (c) 2013 Society of Plastics Engineers