Characterization of magnetic tapes and substrates

Ultra-thin advanced magnetic tape substrates are shown to have superior characteristics when compared to PET. In particular, PEN and ARAMID are viable alternatives to PET with elastic moduli that range from 4-5.4 GPa for PEN, and 10 GPa for ARAMID. Also, the ARAMID material is more isotropic than PET or PEN with a higher glass transition temperature of 277/spl deg/C. Thermal and hygroscopic expansion measurements show that PEN and ARAMID are typically superior to PET. Characteristics of two developmental materials (a polybenzoxazole and a polyimide) are also presented.