| A polyester that is chemically quite similar to PET but which is more temperature resistant. So far available only as biaxially oriented and heat stabilized films, they are semi-crystalline and colorless, either crystal clear or slightly hazy (the latter are available from Goodfellow stock). Compared to their PET equivalents, they start to shrink significantly at 190C rather than 150C and are certified for long term electrical use at 155C rather than 105/130C. Their tensile strengths are similar, but the modulus of PEN films is higher - say 25% at ambient temperatures but several times higher in the 100-150C region. They also have better UV resistance and barrier properties and are more resistant to hydrolysis in alkaline or very hot aqueous conditions. They are, however, more expensive and have a lower flex life. Applications for the films are mainly in the electrical and electronic areas. Information provided by Goodfellow. |
