فهرست نشریات علمی دسترسی آزاد ایران

The present study investigates how incorporating 5 wt.% coffee husk (CH) powder affects the structural and optical characteristics of composite films created from high-molecular-weight polyethylene oxide (PEO). The solution casting method was used to make the PEO-CH composite films. The XRD analysis showed that all of the produced films had a semicrystalline structure. The FTIR analysis confirmed the presence of multiple functional groups in the matrix of PEO. The observed absorption bands correspond to C–H stretching and bending vibrations, O–H groups, and a characteristic C–O–C triplet bond, indicative of the polymer’s molecular structure. FESEM examination demonstrated that coffee husk particles exhibited plate-like morphology. The EDX elemental analysis of pure PEO films showed that they contained 54.6% carbon and 45.4% oxygen, while the doped films had additional elements: 55.2% carbon, 43.7% oxygen, 0.4% aluminum, 0.3% silicon, 0.1% potassium, 0.1% calcium, and 0.2% nickel. The optical properties of the PEO-based composite films, which were 97.5 μm and 83.5 μm thick, were studied using methods like measuring how much light passed through and how much was reflected and analyzing the refractive index and extinction coefficient. The UV-Vis absorption spectrum of pure PEO exhibited a single absorption peak at 240 nm. Incorporation of CH reduced both direct and indirect bandgap energies from 4.5 eV to 2.9 eV and from 3.3 eV to 1.5 eV, respectively.