03-13-2009, 12:53 AM
I work as a technical service engineer in the plastic industry, I remember that some time ago we sent out a PET resin sample to a company that was making photographic film for medical imaging applications. The business ended few years later, when medical imaging applications moved from images recorded on film to images recorded on CDs and DVDs. PET (polyethylene terephtalate) is just one member of the polyester family, the support of the APS film was made of PEN (polyethylene naphtalate), which is even better than PET in terms of properties, albeit far more expensive. In order to make it suitable for film application, PET is extruded and the film undergoes a post-processing called biaxial orientation, during which it improves its mechanical properties.