Rice straw cellulose microfiber reinforcing PVA composite film of ultraviolet blocking through pre-cross-linking.

Rice straw cellulose microfiber (CMF) was obtained through the gentle low-temperature phase transition method. Then, NaIO4 was utilized to modify CMF by selective oxidation to prepare aldehyde CMF (a-CMF) to improve the reactivity of the CMF. Finally, the a-CMF reinforced polyvinyl alcohol (PVA) composite films were prepared through a pre-cross-linking and solvent casting approach. The cross-linking network formed by a-CMF and PVA through the aldolization reaction significantly improved the mechanical properties of the a-CMF/PVA composite film. The tensile strength of a-CMF-2/PVA was 37.54 ± 0.77 MPa, which was higher than 25.88 ± 2.97 MPa of the pure PVA. SEM results showed that the fracture surface of the a-CMF/PVA composite film with the cross-linking network was smooth. In addition, prepared a-CMF-2/PVA composite films had a transmittance of over 80 % in the visible light range, and also possessed excellent UV blocking property.

Synthesis of Sodium Carboxymethyl Cellulose/Poly(acrylic acid) Microgels via Visible-Light-Triggered Polymerization as a Self-Sedimentary Cationic Basic Dye Adsorbent.

In this study, sodium carboxymethyl cellulose/poly(acrylic acid) (CMC/PAA) microgels were successfully synthesized via visible-light-triggered free-radical polymerization to remove methylene blue (MB) from water. The microgels had a loose and porous 3-D network structure, exhibiting excellent adsorption performance. The equilibrium adsorption capacity and the removal efficiency of the microgels reached approximately 1479 mg/g and 97%, respectively, when the initial concentration of MB was 300 mg/L. The adsorption kinetics was well described by the pseudo-second-order model, and the adsorption isotherms followed the Langmuir isothermal model. Notably, CMC/PAA microgels could naturally settle and be separated from the MB solution. Furthermore, the recovery efficiency of the regenerated CMC/PAA microgels reached approximately 94% after five adsorption-desorption cycles. Therefore, the microgels could be used as promising adsorbents due to the advantages of high adsorption capacity, fast removal rate, and reusability.