Evaluation of the Effect of Oxidizing Bleaches on the Visual and Structural Properties of Paper

Paper turns yellow over time. Bleaching with oxidizing agents is one of the most common methods, which creates a colorless result by breaking down the light-absorbing chromophores. In this research, the changes in the properties of paper by applying oxidizing agents are studied. The paper samples were characterized by colorimetric, infrared spectroscopy, tensile, acidity, and SEM microscopes. Four oxidizing solutions were deployed for whitening the samples of Whatman paper using the Immersion method, including Hydrogen Peroxide (2 % V/V), Sodium Peroxide (2 % W/V), Potassium Periodate (2 % W/V), and Potassium Persulphate (2 % W/V) all solved in distilled water. The samples were treated within 48 hours, and characterizing tests were deployed. The results show that hydrogen peroxide with the highest tensile strength (17.75 Nm/g) and the lowest color difference (∆E= 1.48) after accelerated aging has the best performance among other samples. Also, hydrogen peroxide can be improved tensile strength, increase brightness, reduce yellowing, cause fibers stability, and keep the paper at an almost neutral acidity.