Effect of Lithium Salts on the Optical Properties of Poly Acrylonitrile/Poly Methyl Methacrylate Blends

Polymer blends from Poly Acrylonitrile/Poly Methyl Methacrylate (PAN/PMMA) with different blend ratios (۸۰/۲۰,۷۵/۲۵,۷۰/۳۰,۶۵/۳۵, and ۶۰/۴۰) wt% undoped and doped with various lithium (Li) salts (LiCO۳, Li۲SO۴H۲O, and LiCl) at ۲۰ wt %. Different techniques were employed to investigate the composition and optical properties of the prepared blend samples undoped and doped with Lithium salts like FT-IR and UV-Visible spectroscopies. The optical properties analysis declared that the energy gap increased from (۴.۰ eV to ۴.۲۰ eV) by increasing of PMMA ratio from ۲۰ to ۴۰ wt %. In contrast, the energy gap reduced and shifted toward the low energy side by adding lithium salts; the minimum energy gap value was ۲ eV obtained from ۶۵ % PAN and ۳۵ % PMMA doped with Li۲CO۳. The optical constants were determined and plotted as a function of wavelength in the range (of ۱۰۰-۱۱۰۰) nm. The general results showed that the optical constants (n, εr, and εi) for undoped blends increased with the PMMA ratio from ۲۰ to ۳۵ wt%. In contrast, all-optical constants were grown with the addition of lithium salts.