The structural and optical properties of PVA/CMC copolymer cured by UV-irradiation at different times

Abstract

Polyvinyl alcohol (PVA)/Carboxymethyl cellulose (CMC) blend films with equal amounts (0.25 g) of both polymers were prepared via a simple and low-cost comparative casting method. Then, the PVA/CMC blend films were exposed to UV-irradiation for varied time intervals (1, 12, 26, 32, 40, and 48 h). The UV-irradiations effect on the physical properties of as-prepared films including the structure, morphology, composite and optical properties (transmittance, absorbance, and band-gap (Eg)) was examined. FESEM images display that UV-irradiation has a strong effect on the shape of PVA/CMC blend films. The XRD patterns show various crystalline qualities in the microstructure of as-synthesis samples. The FTIR spectra demonstrate that UV-irradiation time and CMC film had a positive impact on the blend polymer structure since covalent connections were formed between CMC and PVA. Furthermore, the analysis results of optical inspections show the absorbance of the PVA/CMC films was improved with an increment of irradiation times from (1 to 40 h). An important tunning of Eg values of blend films was realized. It shows a slightly increased from (4.64 eV to 4.84 eV) with increasing irradiation time from (1 to 40 h). The Eg value (3.21 eV), however, displayed an inverted behaviour due to an increased irradiation time of 48 h, this reduction can be ascribed to the creation of defects inside the blend band gap. Finally, the physical properties modification of PVA/CMC blend films using UV-Irradiation makes it an amazing contender in the optoelectronic area.