Preparation and Application of UV-Resistant Cellulose Transparent Paper

Using sulfate softwood pulp paper as the substrate, high transparency and high haze UV-resistant transparent paper was prepared by filling tannic acid(TA) and sodium carboxymethyl cellulose(CMC-Na) into the pores of the substrate through an impregnation method. The structure and properties of the UV-resistant transparent paper were comprehensively analyzed, exploring the effects of the quantitative amount of the paper substrate and the addition of CMC-Na on the transparency and haze of the transparent paper, as well as the effect of TA addition on the transparency and UV shielding efficiency of the transparent paper. The mechanisms behind the transparency and haze generation of the transparent paper were also investigated. The results showed that the transparency and haze of the paper were mainly affected by pore size and the alternating arrangement of cellulose crystalline zones. CMC-Na impregnation could improve transparency and reduce haze. When the ratio of paper, CMC-Na, and TA was 1∶1.39∶0.07, the transparency and UV-blocking performance of the transparent paper reached 87.2%(600 nm) and 92.9%(320 nm), respectively, while the haze remained at 71.5%(600 nm). The UV-resistant transparent paper exhibited excellent aging resistance(exposed to a 365 nm UV lamp with a light intensity of 18.52 W/m² for 100 h) and outstanding mechanical properties(71.49 MPa). Through a simple process of acetic acid proton exchange(10 min) and ethanol desalination(10 min), the water contact angle of the material significantly increased(78.7°). The protonation treatment altered the chemical properties of the material's surface, while the desalination process removed surface impurities. This dual treatment method effectively enhanced the material's water resistance in humid environments.