Improving the flexibility, electrical conductivity and light absorption of carboxymethylcellulose and polyvinyl alcohol solutions and thin films by the addition of different concentrations of citric a

The aim of this research is to improve certain physical properties of carboxymethylcellulose, polyvinyl alcohol and benefit from this improvement in many areas. CMCHV and PVA solutions were prepared by dissolving them in twice-distilled water, then different concentrations of citric acid (0.0, 40, 57, 66, 72%) were added, also a new solutions for the samples were prepared in the same way then the solutions were poured onto a level glass plate and allowed to dry at room temperature (30oC), so thin films almost 0.01 mm thick were formed. After that, the ultraviolet absorbance of the solutions, the electrical conductivity of the samples, and the mechanical properties of the thin film samples were measured. From the results, it is clear that with increasing acid concentration, the UV absorbance of all solution samples increased and thus the spectral transmittance through the samples decreased and the solutions became somewhat opaque. The optical density of the solution of each of CMCHV and PVA increased. The optical density increase for solution CMCHV was greater than that for solution PVA at a certain concentration of acid, also the optical density for solution PVA was greater than that for solution CMCHV at another concentration. as well as the conductivity of all samples (solutions and thin films), increases with increasing citric acid concentration, so that the conductivity of CMCHV increases more than the conductivity of PVA. For the CMCHV solutions, two peaks appeared at wavelengths (198nm) and (223nm) in the absorption curve of the ultraviolet spectrum, and three peaks at wavelengths (198 nm), (203 nm) and (224) appeared for the PVA solutions. The conductivity of CMCHV thin films increases more than that of PVA thin films with increasing temperature. For elastic properties of samples, the citric acid concentrations reduce the elasticity of CMCHV thin films and increase the elasticity PVA of thin films. These results can be used in many fields, such as the oil field, medicine field, or scientific research.