Mechanical study of metallized polyethylene terephthalate (PET) films

Mechanical properties such as Young's modulus (Y), storage modulus (E′), glass transition temperature (Tg), tensile strength (σ), and yield strength (σy) of metallized polyethylene terephthalate (PET) films have been measured using Dynamic Mechanical Analyser (DMA). Commercially available PET film thickness of 20 μm has been used for metallization. Aluminium (Al) and lead (Pb) have been coated separately on PET films by vacuum thermal evaporation method to form metallized PET films. The Tg of Al-PET and Pb-PET films has been found to be 112.3 °C and 111.2 °C respectively whereas Tg of commercial PET film is 89.7 °C. The stress–strain curves of metallized PET films at room temperature and at different elevated temperatures have been taken which show significant temperature dependence. In particular, the yield strength shows a decrement with increasing temperature.