Nanocomposites porous film based on polypropylene (PP) and titanium dioxide (TiO2) nanoparticles were prepared by the uniaxial stretching method. Effects of drawing temperature, extension rate, stretching ratio and composition of the base films on final properties and microstructure of the stretched films were studied. Water vapor permeability results showed significant decrease in permeability of the films stretched at temperatures higher than 60°C. Water vapor permeation in the porous nanocomposite films had a direct relation with nanoparticle content, extension rate and stretching ratio. Study on morphology of stretched films, using SEM, revealed that the pores form due to PP/TiO2 interfacial debonding at lower stretching ratio while higher stretching ratios cause an enlargement of the pores and formation of PP fibril structure parallel to the stretching axis. Apparent porosity values, BET surface area measurement and quantification of dye absorption on pores showed smaller dependency on process parameters.
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