Unformatted text preview: this process is what we usually mean when we say orientation. Biaxial orientation is orientation along two perpendicular directions. Uniaxial orientation is orientation in one direction. If we want uniaxially oriented film, we stretch it in the machine direction (MD). That causes the polymer molecules to line up in the direction of the stretch, and results, for example, in an increase in MD tensile strength. However, we pay a price – the CD strength will decrease. So, if we want to improve strength (or other properties) in both the MD and CD, we can use biaxial orientation. Then, the molecules tend to line up in the plane of the film, and strength improves in both these directions. Film Casting...
View Full Document
- Spring '08
- Tensile strength, biaxial orientation