Polypropylene is an attractive candidate material for packaging applications because of its low cost and good thermal stability. Commercial polypropylene films are typically oriented by a tentering process in which an extruded film is quenched, reheated, and biaxially drawn into a film. Orientation improves both the mechanical and gas-barrier properties of the films. To achieve appropriate knowledge of this product, a fundamental understanding of each portion of the BOPP, is required.