Deacidification and self-cleaning are important for the preservation of paper documents. In this study, nano-CaCO₃ was used as a deacidification agent and stabilized by nanocellulose (CNC) and hydroxypropyl methylcellulose (HPMC) to form a uniform dispersion. Followed by polydimethylsiloxane (PDMS) treatment and chemical vapor deposition (CVD) of methyltrimethoxysilane (MTMS), a hydrophobic coating was constructed for self-cleaning purposes. The pH value of the treated paper was approximately 8.20, and the static contact angle was as high as 152.29°. Compared to the untreated paper, the tensile strength of the treated paper increased by 12.6%. This treatment method endows the paper with a good deacidification effect and self-cleaning property, which are beneficial for its long-term preservation.

The fabrication of directionally driven oil-water separation materials has great significance for the removal of oil spills and organic pollutants. In this study, an oil-water separation aerogel capable of directionally adsorbing oil was designed using an anisotropic wood aerogel with a layered structure and a top-down fabrication strategy. Specifically, a magnetic wood-based superhydrophobic aerogel (methyltrimethoxysilane (MTMS)/Fe₃O₄ wood aerogel) was developed through the in situ co-precipitation of Fe₃O₄ nanoparticles and chemical vapor deposition. Owing to its highly porous structure, lipophilicity, hydrophobicity (water contact angle of 160°), and high compressibility, the MTMS/Fe₃O₄ wood aerogel exhibits excellent oil-water separation performance and compression cycle stability. Additionally, the Fe₃O₄ endows the material with excellent magnetic and photothermal conversion capabilities. These excellent properties make MTMS/Fe₃O₄ wood aerogel a promising recyclable and sustainable oil-water separation material.

Hydroxypropyl methylcellulose acetate succinate (HPMCAS) was successfully synthesized from the reaction of hydroxypropyl methylcellulose with succinic anhydride and acetic anhydride in an acetone/pyridine system. Products with different contents of succinyl groups and acetyl groups were prepared by varying the reaction conditions. In the acetone/pyridine system, equipment corrosion does not occur, the product is easy to wash, and the solvent can be recycled. By varying the concentration of the esterifying agents, products with different ratios of acidic groups can be obtained. Under the optimum conditions, the obtained products had an average molecular weight between 5.39×10⁴ and 5.41×10⁴, a number average molecular weight from 4.97×10⁴ to 5.13×10⁴, and a polydispersity index from 1.05 to 1.08. The products dissolved well in acetone and methanol, and formed films on a mold. The films had good pH-sensitivity, tensile strength, and thermal stability. The formed films could dissolve in solutions with a pH value ranging from 5.4 to 6.4, and are therefore suitable for use as an enteric coating for pharmaceutical dosage forms.

Sugarcane bagasse (SCB) is an important by-product in the sugar industry. It is a source of cellulose fibers or cellulose for paper mills and textiles factories. In this study, SCB was ethyl etherified in tetrahydrofuran (THF) after alkali pretreatment. The alkali concentration for the pretreatment, the ratio of ethyl bromide (EtBr) to dried SCB in the reaction, reaction time, and temperature were investigated for the etherification of SCB. The ethoxyl content and characterization of the product were determined using headspace gas chromatography (HS-GC), Fourier Transform Infrared (FT-IR) and ¹³C-NMR spectroscopy, respectively. It was found that SCB was well-etherified with EtBr in alkali-THF. Upon ethylation of SCB, the ethoxyl content of the product was high when the alkali concentration and the ratio of EtBr to dried SCB were controlled from 50% to 75% and 4:1 (V/w) to 6:1 (V/w), respectively. The reaction occurred optimally when the temperature was controlled below 110℃; above this temperature, the degree of etherification decreased. The thermal stability of ethylated SCB was higher than that of SCB but slightly lower than that of commercial ethyl cellulose. Ethylated SCB has the potential to form composites with many materials because it is soluble in a wide variety of solvents.

Cellulose nanocrystal (CNC) prepared by hydrolysis of cotton linters with sulfuric acid was used to react with chloroauric acid to manufacture a gold nanoparticle/CNC composite. The composite was then graft-copolymerized with N-isopropylacrylamide to obtain a photo-thermal ultrafine gold nanoparticles/CNC-based hydrogel. The hydrogel was studied by performing scanning electron microscopy, and it was found that the prepared hydrogel had a network structure. The temperature of the hydrogel increased from 25℃ to 39℃ and its volume decreased by 30% when it was exposed to visible light (400~750 nm) for 1 h. The experiment results indicated that the prepared photo-thermal CNC-based hydrogel has thermal responsiveness and photo-thermal properties.

Cellulose nanocrystal was modified with poly(N,N-diethylaminomethyl methacrylate) to prepare an adsorbent containing amine groups for removing anionic dyes from waste water. The prepared adsorbent was characterized by Fourier-transform infrared spectrometry (FT-IR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The adsorption was affected by various factors, such as the contact time, adsorbent dosage, dye solution pH value, initial dye concentration, and ionic strength. The results revealed that amine functional groups mainly contribute to the adsorption of azo dyes (AO7). The adsorbent showed pseudo-secondorder adsorption kinetics, indicating that the dye molecules were chemisorbed on the adsorbent. The adsorption isotherm was found to fit better with the Langmuir isotherm model than with the Freundlich isotherm model.

Enzymatic pretreatment of pulp is demonstrated to be potentially effective for decreasing the energy consumption in the refining process.Herein, a neutral cellulase was utilized for the pretreatment of bleached softwood pulp in order to improve the refining performance.Cellulase pretreatment effectively improved the drainability of the pulp and could thus reduce the energy consumption in the refining process.The beating degree of the pulp was significantly improved at 6000 PFI revolutions, at which a maximum increase of 70% could be obtained.The water retention value (WRV) of the pulp increased by 17% after treatment with cellulase at a dosage of 5 IU/g, and the fibers could be easily torn apart after enzymatic treatment.To achieve the same beating degree, the refining time could be shortened by 80% when the pulp was treated with cellulase.Using a low dosage of cellulase, the freeness of the pulp increased rapidly without deterioration of the mechanical properties.

Bamboo was used as raw material for unbleached pulp production.An acetic acid prehydrolysis process was employed before the pulping process.The effect of acetic acid prehydrolysis on pulp properties was investigated.The results showed that some components, such as hemicellulose and extractives, were degraded or dissolved in the prehydrolysis process prior to kraft pulping.SEM images of the substrate after treatment indicated that the parenchyma cell wall was thinner, and the size of pores between fiber bundle cell walls was larger.The pulping results showed that acetic acid prehydrolysis could improve the pulp quality and make the pulp easier to bleach.The brightness of the pulp reached 59.6%ISO with a single oxygen delignification step.The acetic acid prehydrolysis decreased pulp viscosity and fiber length, but not significantly.The amount of parenchyma cells in the pulp was reduced, which was beneficial for papermaking and improving mechanical strength of paper.This procedure has good potential for unbleached pulp production.

Hydroxypropyl methyl cellulose (HPMC)-based hybrid nanocomposites reinforced with bacterial cellulose nanocrystals (BCNC) were prepared and characterized. The HPMC nanocomposites exhibited good thermal stability, with a thermogravimetric peak temperature of around 346℃. The addition of BCNC did not significantly affect the thermal degradation temperature or improve the transparency of HPMC nanocomposites. However, the addition of BCNC favorably affected the light scattering properties of the nanocomposites and enhanced mechanical properties such as tensile stress and Young's modulus from 65 MPa and 1.5 GPa up to 139 MPa and 3.2 GPa, respectively. The oxygen permeability of the HPMC nanocomposites also increased with increase in the amount of BCNC added.