Oxygen barrier properties of biaxially oriented polypropylene/polyvinyl alcohol blend films

The biaxially oriented PP/PVA blend film was prepared and had the higher oxygen barrier property by about 130 times than that of a biaxially oriented PP film. When the viscosity ratio (eta(d(PVA))/eta(m(PP))) decreased, the dispersed PVA phase was developed into platelets during stretching process. Oxygen permeability was dependent on the number and size of PVA platelet. However, the Oxygen permeability was not sensitively changed in above 25 wt% of PVA. To obtain excellent barrier property, the optimum amount of plasticizer and initiator was required. A pasticizer was related to the size and degree of crystallization of PVA platelet. An initiator played the role of a compatibilizer. The oxygen barrier was enhanced with increasing the viscosity of PP and draw ratio. The higher viscosity of PP was advantageous for preventing the delamination of a blend film, and the moisture vapor permeability was not affected with the laminar structure. As a result, the biaxially oriented PP/PVA blend film had the potential of substituting for the PVDC coated BOPP film. (C) 2003 Elsevier Ltd. All rights reserved.