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A precooled aqueous solution of 7 wt% NaOH/12 wt% urea was used to dissolve cellulose up to a concentration of 2 wt%, which was then coagulated in an acetone/water mixture to regenerate cellulose film. The volume ratio of acetone to water (φ) had a dominant influence on film dimensional stability, film-forming ability, micromorphology, and mechanical strength. The film regenerated at φ=2.0 showed excellent performance in both dimensional stability and film-forming ability. Compared to that from pure acetone, the cellulose film from the acetone/water mixture with φ=2.0 was more densely interwoven, since the cellulosic fibrils formed during regeneration had pores with smaller average diameter. The alkali capsulated in the film during film formation could be released at quite a slow rate into the surrounding aqueous solution. The regenerated cellulose film with adjustable structure and properties may have potential applications in drug release and ultra filtration., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Blending modification is used to improve the hemocompatibility of cellulose acetate (CA) dialysis membranes while endowing the CA membrane with endotoxin scavenging and antibacterial capabilities. First, polydopamine (PDA) and polyethylenimine (PEI) are used as negatively charged and positively charged moieties, respectively, together with cellulose nanocrystals (CNCs) to construct mixed charge CNCs (PEI‐PDA@CNCs). Then PEI‐PDA@CNCs is blended with the CA casting solution, and the modified CA dialysis membrane is prepared through a phase inversion process. Through biocompatibility, adsorption, antibacterial, and filtration experiments, various properties of PEI‐PDA@CNCs modified CA membrane (PDCA) are systematically tested. The results show that the PDCA membrane exhibited good blood compatibility and noncytotoxicity. At the same time, the PDCA membrane has antibacterial properties and excellent endotoxin adsorption capacity. Compared with the CA membrane, the clearance rates of PDCA membrane for Staphylococcus aureus and Escherichia coli reach 54.0% ± 1.5% and 52.9% ± 5.9% respectively. In the dynamic adsorption experiment, the adsorption capacity of PDCA membrane for endotoxin increases to 2322.1 ± 45.9 EU/g. The research results indicate that PEI‐PDA@CNC‐modified multifunctional CA membrane with endotoxin adsorption and antibacterial properties has potential application prospects in the fields of hemodialysis and blood purification. [ABSTRACT FROM AUTHOR]

A bio‐based nanocomposite optical film was obtained through a simple sol‐gel process and solution casting. The dispersion effect of cellulose nanocrystals (CNCs) gel and the optical properties, mechanical performance and thermal stability of CNC‐doped cellulose triacetate (TAC) films (TAC−X) were systematically evaluated. The results show that CNCs can be well dispersed in hydrophobic organic solvents and TAC matrices through the sol‐gel process. TAC−X film has excellent optical properties, its light transmittance is above 92 %, its haze value and birefringence are low, ranging from 0.21±0.01 % to 0.38±0.02 %, and (1.64±0.26)×10−6 to (2.49±0.50)×10−6 respectively. When doped with 2 wt % CNCs, the tensile strength and Young's modulus of the TAC‐2 film were 33.0 % and 30.1 % higher than those of the pure TAC film, separately. At the same time, the TAC−X film also maintains good thermal stability, with its glass transition temperature and maximum decomposition temperature falling between 215–216 °C and 366–368 °C respectively. The simple sol‐gel process provides a convenient and efficient way to use CNCs doping to enhance the physical and mechanical properties of TAC optical films. [ABSTRACT FROM AUTHOR]

Apple wood waste (AWW), mainly tree trucks, is collectible lignocellulosic biomass from orchard rotation. The biorefinery of AWW is challenging because of the hard and dense structure. In the present work, chemical composition determination and microstructure observation was performed for the first time on AWW. Alkali-preimpregnation-assisted soda cooking (APSC) was developed to separate cellulose a pulp and lignin from AWW. APSC attained pulp yield of 34.2% at 23% NaOH, showing a 13.2% improvement compared to conventional soda cooking (SC). Fiber length analysis showed APSC-AWW pulp consisted mainly of medium and short fibers, which means blending with long-fibered pulp to enhance the physical strength of pulp sheets. A blend of APSC-AWW pulp and long-fibered pulp in the proportion of 80:20 attained comparable physical strength to hardwood kraft pulp. ASPC-AWW lignin was separated from spent liquor by acidification and then purified by dialysis desalination. The purified ASPC-AWW lignin showed a weight-average molecular weight of 4462 g/mol, similar to softwood kraft lignin but more uniform. Structural analysis revealed that ASPC-AWW lignin was composed of a syringyl unit (S), guaiacyl unit(G), and p-hydroxyphenyl unit (H), and an S unit was dominant with an S/G/H ratio of 74.5:18.2:7.3. It is believed the utilization of fruit tree wood waste as the feedstock of biorefinery is attractive to countries without sufficient forestry resources. Furthermore, the developed APSC is based on conventional SC, which ensures the feasibility of an industrial application. [ABSTRACT FROM AUTHOR]

The use of non-degradable plastic mulch film causes significant environmental pollution and poses a threat to human and ecological safety. To address this issue, a viable solution is to develop bio-based and biodegradable paper mulch films to replace non-biodegradable ones in agricultural soils. In this study, a green and straightforward process was used to synthesize lignin-based polyurethane (LPU), which was then coated on cellulose paper (CP) of low basis weight of 30 g/m2 to fabricate a composite LPU/CP mulch film. An ultra-thin and lightweight LPU/CP mulch film was successfully fabricated with basis weight, thickness, and specific density of 40 g/m2, 80 µm, and 0.5 g/cm3, respectively. It was observed that surface coating was very effective in improving the physical strength of composite film as indicated by the improvement of tensile index from 19.3 N·m/g of CP to 65.0 N·m/g of LPU/CP mulch film. Moreover, LPU/CP mulch film presented excellent water resistance properties as suggested by the water contact angle of 107° and the water vapor transmission rate of 639.3 g/m2·day. LPU/CP mulch film also shows a balance between degradability and durability that it starts to break down into fractions after being buried for 28 days as a result of microbiological degradation. This work provides a feasible technology for fabricating eco-friendly, cost-effective, and biodegradable paper mulch film. [Display omitted] • Lignin-based polyurethane was successfully synthesized. • LPU/CP mulch film was fabricated through LPU coating on cellulose paper. • LPU/CP mulch films showed excellent water resistance, water vapor barrier and thermal insulation performance. • Degradability and mechanical strength of LPU/CP is beneficial to agricultural application. [ABSTRACT FROM AUTHOR]

Formic acid/water binary solvent extraction with formic acid fraction lower than 77.5% (w/w) of azeotrope was used to extract hemicellulose-derived saccharides from poplar wood at various levels of severity. The highest xylose yield of 77.8% and arabinose yield of 93.5% were obtained at 120 °C and 1 h. To reduce cellulose hydrolysis and facilitate downstream xylose crystallization, mild conditions at 90 °C and 4 h was chosen as optimum severity, which led to the highest xylose fraction of 81.7% in all saccharides extracted, with a remarkable xylose yield of 73.1%. Mass balance analysis showed that 5.84% of xylan was degraded, but only 0.25% of xylan ended up as furfural at optimum severity. The proposed extraction process has high feasibility for industrial application since the low formic acid fraction in solvent allows simple recovery and concentration of used solvent. [ABSTRACT FROM AUTHOR]

Full components utilization of corn stalk was investigated by the combine processes of prehydrolysis and alkaline sulfite cooking. Prehydrolysis was employed to remove hemicelluloses prior to cooking. Glucose yield of 76.8 g/kg and xylose yield of 118.4 g/kg corn stalks were obtained from the hydrolysis of hemicelluloses at 150 °C for 3 h. Significantly, cellulose was largely preserved during prehydrolysis as indicated by the pulp yield from 54 % to 62 % from the alkaline sulfite cooking. Paper sheet showed superior physical strength over hardwood pulp, e.g. tensile index 97.4 N·m/g, tear index 6.6 mN·m2/g and burst index 5.2 kPa·m2/g. In addition, lignin in spent liquor of alkaline sulfite cooking was recovered as lignosulfonate surfactant which reduced the surface tension of water to 38.2 mN/m at a concentration of 15 g/L. The combined processes of prehydrolysis and alkaline sulfite cooking enables full utilization of cellulose, hemicelluloses, and lignin, and therefore has great potential to industrial application. [Display omitted] • Hemicelluloses in corn stalk were extracted by prehydrolysis prior to alkaline sulfite pulping. • Highest sugar yield of 287.7 g/kg corn stalk was obtained from prehydrolysis. • Corn stalk pulp from alkaline sulfite cooking showed superior strength over hardwood pulp. • Lignosulfonate was formed during pulping and showed excellent surfactivity. [ABSTRACT FROM AUTHOR]

• Pith and leaf containing corn stover was fractionated in aqueous formic acid system. • Paper made from fractionation residue showed comparable strength to conventional paper. • Xylose yield reached 11.2 % on the weight basis of untreated rind and pith. • Lignin showed less aliphatic hydroxy groups by 37.9 %–46.6 than conventional technical lignins. Corn stover is collectable byproduct of grain production in agriculture. In this work, pith and leaf containing corn stover was fractionated into cellulose fibers, sugars, and lignin with remarkable yields of 38.9 %, 5.2 % and 25.4 %, respectively by one-step treatment using 85.0 % aqueous formic acid (FA) at conditions of 130 °C for 30 min. Paper sheet was prepared using the obtained cellulose fibers and showed excellent physical strength in terms of tensile index of 50.1 N·m/g, burst index of 3.0 kPa·m2/g and tear index of 6.1 mN·m2/g, comparable to the paper sheet made of conventional alkaline pulp. The obtained sugars contain 61 % of xylose, 17 % of glucose, 15 % of arabinose, 6 % of galactose and 1 % of mannose. The obtained water-insoluble lignin showed less aliphatic hydroxy groups by 37.9 %–46.6% than conventional technical lignins. This property is helpful to the lignin valorization in biodegradable polymer industry as interface-compatible fillers. [ABSTRACT FROM AUTHOR]

• QHT achieved 82% cellulose conversion from a low cellulase dosage of poplar. • QHT removed >85% hemicelluloses and ~30% lignin in poplar in 5–25 min. • QHT increased crystallinity and special surface area of poplar. To elevate the glucose yield from the enzymatic hydrolysis of poplar wood for bio-ethanol production, quick hydrothermal treatment (QHT) was conducted at 200 °C for a short period of time from 5 min to 25 min. It was found that the QHT could remove >85% of the hemicelluloses and ~30% of the lignin in the poplar wood, and achieve 82% cellulose conversion at a low cellulase dosage of 10 FPU/g substrate. The enhancement digestibility of poplar wood was ascribed to the higher accessibility of cellulose, as the specific surface area of the substrate increased from 3.0 m2/g to 7.1 m2/g from the of untreated wood to the QHT-treated wood. The results demonstrate the improvements in digestibility and hydrolysis rates after QHT. [ABSTRACT FROM AUTHOR]

Sequential Wood fractionation by flowing acid hydrotrope p -TsOH. • Sequential fractionation (SF) of woody biomass using acidic hydrotrope was developed. • Hemicellulose sugars, lignin, and cellulose were obtained stepwise from SF of wood. • Up to 83 % lignin dissolution was achieved with well-preserved structure. • Crystalline structure of cellulose was kept well in the wood residue after SF treatment. Sequential fractionation (SF) of woody biomass using acid hydrotrope p -toluenesulfonic acid (p -TsOH) as reaction medium was investigated. Hemicellulosic sugars, lignin, and cellulose-rich solid were harvested as the main products from the stepwise deconstruction of biomass as results of hemicelluloses hydrolysis and subsequent lignin dissolution. The first step of SF employed 2wt% p -TsOH, far below the minimum hydrotrope concentration (MHC) of 11.5wt%, and reached 23.5 % of biomass dissolution with 55.1 % removal of xylan from wood at 120 °C for 2 h. The second step of SF was characterized with mild conditions of 100 °C, 40wt% p -TsOH, and one hour, and achieved 83 % lignin dissolution with well-preserved structure. The obtained cellulose-rich solid from SF showed a high crystallinity index of 73.3 % and a complete recovery of glucan. This means excellent performance of SF for sustainable bio-refining. [ABSTRACT FROM AUTHOR]

• Aqueous NMMO is used to modify cellulose nanocrystal photonic films. • CNC photonic films can be swollen by NMMO and show red-shifted color. • NMMO-treated CNC films display reversible responsive colors to humidity changes. • Aqueous NMMO is used as an ink to depict responsive photonic patterns on CNC films. A type of cellulose solvent, i.e., aqueous N -methylmorpholine- N -O xide (NMMO) solutions, was used to modify cellulose nanocrystal (CNC) photonic films. CNC films can be swollen by NMMO, resulting in red-shifted reflected colors. The swelling effect is supposed to come from NMMO permeation into the crystalline regions of individual CNCs and intercalating in between CNC particles. When NMMO was removed, the reflected colors of CNC films blue shifted because of the reduced helical pitches. NMMO-treated CNC films display reversible responsive colors to humidity changes in several minutes. Increasing NMMO content allows CNC films to enlarge the responsive color range. Aqueous NMMO can be used as an ink to depict responsive photonic patterns on CNC films. This post-treatment approach to producing responsive colors and photonic patterns in CNC films may be applied to the areas of sensor, anti-counterfeiting, and decoration. [ABSTRACT FROM AUTHOR]