Facile fabrication of cellulose-based hydrophobic paper via Michael addition reaction.

The inherent highly hydrophilic feature of cellulose-based paper hinders its application in many fields. Herein, a cellulose-based hydrophobic paper was fabricated based on surface chemical modification. Firstly, the hydrophobic acrylate components were bonded to the cellulose acetoacetate (CAA) fibers to obtain CAA graft acrylate (CAA-X) fibers through Michael addition reaction. Subsequently, CAA-X fibers were processed into paper via wet papermaking technology. The resulting paper exhibited good hydrophobic performance (water contact angle was up to 135°) with an air permeability of 24.8 µm/Pa·s. The hydrophobicity of paper was very stable and remained even after treating with different solvents. Moreover, the hydrophobic properties of this paper could be adjusted by changing the type of acrylate component. It should be noted that the surface modification strategy has no obvious effects on the whiteness (79.8%), writing, and printing properties of the cellulose fibers. Thus, it is a simple, benign, and efficient strategy for the construction of cellulose-based hydrophobic paper, which has great potential to be used in paper tableware, oil-water separation, watercolor protection, and food packaging fields.

Facile construction of photocatalytic cellulose-based sponge with stable flotation properties as efficient and recyclable photocatalysts for sewage treatment.

Dispersion and recycling of powdered nano-photocatalysts for water purification is still not an easy task. The self-supporting and floating photocatalytic cellulose-based sponges ware conveniently prepared by anchoring BiOX nanosheet arrays on cellulose-based sponge's surface. The introduction of sodium alginate into the cellulose-based sponge significantly enhanced the electrostatic adsorption of bismuth oxygen ions and promoted the formation of bismuth oxyhalide (BiOX) crystal nuclei. Among the photocatalytic cellulose-based sponges, the sponge (BiOBr-SA/CNF) modified with bismuth oxybromide displayed excellent photocatalytic ability for photodegrading 96.1 % rhodamine B within 90 min under 300 W Xe lamp irradiation (λ > 400 nm). The loading of bismuth oxybromide on cellulose-based sponge's surface improves the flotation stability of the cellulose-based sponge. Benefiting from excellent load fastness of bismuth oxybromide nanosheet and flotation stability of BiOBr-SA/CNF sponge, after 5 cycles of recycling, the photodegradation rates of BiOBr-SA/CNF sponge to rhodamine B remained above 90.2 % (90 min), and it also has excellent photocatalytic degradation effect on methyl orange and herbicide isoproteron. This work may provide a convenient and efficient method to construct self-supporting and floating photocatalytic sponges using cellulose based materials as substrates for sewage treatment.

Scalable Fabrication of Highly Breathable Cotton Textiles with Stable Fluorescent, Antibacterial, Hydrophobic, and UV-Blocking Performance.

Multifunctional cotton textiles that are highly breathable are desirable in a broad range of applications. However, it is still a big challenge to scale up production of such multifunctional cotton textiles. Herein, we developed a simple, scalable, and benign strategy to fabricate highly breathable multifunctional cotton textiles via mild surface modification. The 1,4-dihydropyridine (DHP) ring and gentamycin sulfate (GS) molecules were firmly attached to the cellulose chains under room temperature via a one-pot method. The resulting modified cotton textile showed integrated performances with bright fluorescence, good antibacterial behavior, hydrophobic behavior (contact angle of 134°), and UV-blocking (UPF being up to 69.2), which are very stable toward washing and various solvents. There is no obvious change in the whiteness, thermal stability, and mechanical performance of cotton fabrics after the surface modification. What's more, the air permeability of the modified cotton fabric was up to 31.3 (cm3/cm2)/s. This study not only focuses on the materials design and large-scale fabrication but also provides stable and multifunctional cotton textiles with broad application prospects for many fields.

Real-time monitoring of multicomponent reactive dye adsorption on cotton fabrics by Raman spectroscopy.

Accurate real-time determination of each dye in combination dyeing is critical to the control of dyeing process, which plays an important role in upgrading the dyeing techniques of textile. In this work, Raman spectroscopy was applied to dyeing baths containing multiple dye species of varying structures to quantitatively monitor the dyeing process of each individual dye. Quantitative models were successfully established by partial least squares (PLS) for all combinations of the nine commonly used reactive dyes studied. The correlation coefficients were greater than 0.99, the root mean squared errors of calibration (RMSEC) were less than 0.2650 and the root mean squared errors of prediction (RMSEP) were less than 0.1340, even for the three-component mixture of Reactive Red 239 (RR239), Reactive Yellow 176 (RY176) and Reactive Blue 194 (RB194), which are similar in structures. The model was shown to be valid in the presence of added electrolytes (sodium sulfates). Real-time adsorption monitoring based on the model revealed that the dyes interacted with one another and competed for active sites. The adsorption kinetics obtained by Raman analysis shed light on dye compatibility and could be used to guide the design of dyeing recipe and dyeing process for optimum color reproduction. In addition, in situ monitoring by Raman spectroscopy maybe integrated with real-time on line control of dyeing parameters for fully automated production of dyed fabrics.