Development of Molecular Orientation during Biaxial Film Tentering of PET

Polyethylene terephthalate (PET) films find wide ranges of applications especially as substrates for magnetic storage and in the packaging market. It is clearly established that mechanical as well as end-use properties of the final films are mainly controlled by the structure and orientation at a molecular level, which originate from the various thermal and deformation conditions experienced by the film throughout its process. Therefore, numerous studies have been devoted to the characterisation of molecular orientation, mechanical properties and end-use properties such as gas permeability or hydrolysis, showing the importance of being able to afford an accurate characterisation of molecular orientation and structure in oriented samples.