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Wrapping paper has an irreplaceable role in the food industry, but the high hydrophilicity of cellulose-based wrapping paper limits its application. Here, we aim to develop a fluorine-free and stable method for preparing the superhydrophobic cellulose-based paper using KH570-modified-n-TiO2 and ε-polylysine (ε-PL) to construct a superhydrophobic surface by layer-by-layer self-assembly. The paper modified by (ε-PL/KH570-modified-n-TiO2)4 multilayers has superhydrophobic and self-cleaning properties after heat treatment. The water contact angle reaches up to 152.8° and the antibacterial rate is close to 100%. The high barrier properties to water vapor better prolong the shelf life of cherries. Therefore, the (ε-PL/KH570-modified-n-TiO2)4 multilayers modified paper can provide a new idea for food preservation. The advantage of the double-layer assembly is that even if the superhydrophobic layer of the wrapper is worn away and lost, the remaining ε-PL is still able to act as a bacterial inhibitor, ensuring that the food is not perishable. [ABSTRACT FROM AUTHOR]

CF4 plasma treatment of a Teflon-like (1,1,1,2 tetrafluoroethane, TFE) chemical spray deposited on paper resulted in an increased level of elemental fluorine on the paper surface. However, TFE molecules undergo bond cleavage and ionization in the presence of the RF-CF4 plasma environment. The abundant fluorine radicals grafted onto the paper surface, via the substitution and opening of the bonds in the cellulose polymers, yielded CFx (x: 1–3) functionalities, as observed by XPS and ATR-FTIR analyses. Lower power (100 W) and treatment times (0.5 min) were sufficient to obtain very highly fluorinated surfaces. The change in the morphology of the surface by the exposure to plasma was complicated because the localized deposition and re-deposition of the plasma-generated molecules on the paper were superimposed on the surface reactions and degradation (etching) at the paper surface. [ABSTRACT FROM AUTHOR]

A novel methodology was used to create a highly porous foam-formed paper that is bonded with highly refined cellulose fiber. In this process, cellulose pulp suspension at various consistencies (0.5, 1.0, 1.5, and 2%) was dispersed in water, followed by foam formation under high shear forces in the presence of a surfactant. Various drying methods were used to achieve foam formation. These included freeze-drying (FD), vacuum-dewatered air-drying (VAD), and dewatered freeze-drying (VFD). Increasing the pulp's consistency and changing the drying techniques from freeze-drying to air-drying resulted in a more compact morphological structure and increased density of foam-formed paper samples. Densification of foam-formed samples was measured using a Dynamic Mechanical Analysis (DMA) machine and a sample with densification at lowest strain value was obtained by a 10 wt% addition of microfibrillated cellulose fiber (MFC). At 10 wt% MFC addition, denser foam-formed paper samples with enhanced microstructure were obtained. Air filtration efficiency and acoustic properties of foam-formed paper were also characterized and optimized by the addition of MFC. [ABSTRACT FROM AUTHOR]

Pyrolysis volatiles and the environmental impact of printing paper, newspaper, and silk were investigated to identify suitable materials for heat-induced eco-printing (HIEP) using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Furthermore, the printing effects of simulated HIEP and the material microstructures were studied using scanning electron microscopy (SEM). The results indicated that the toxicity of pyrolysis volatiles is highest for newspaper, followed by silk and then printing paper, whereas environmental friendliness follows the opposite trend. A high concentration of lignin, the basic structural element of which is phenyl propane, and the presence of halogens in the newspaper led to the generation of more toxic substances during the pyrolysis process. The benzene compounds and heterocyclic compounds in silk also produced high levels of toxic substances. Based on these findings and the higher color permeability of newspaper, printing paper was the most suitable material for HIEP and newspaper was the least suitable. Additionally, silk may still be used in HIEP in small amounts for the production of art, name cards, and clothing tags. [ABSTRACT FROM PUBLISHER]

The plasma duty cycle, in addition to power and exposure time, affects the surface atomic composition of thiophene plasma-treated paper. The elemental carbon and sulfur concentration increased from 56.7% to 78.6% and 0% to 13.4%, respectively, while oxygen decreased from 43.3% to 8.0% with the plasma treatment. Relatively large variations in the deposited film-like layer composition could be realized by changing plasma external parameters. The high-resolution (HR) C1s spectra of the thiophene plasma-treated paper clearly exhibit plasma-induced rearrangements and new sulfur functionalities on the paper surface. After a five-hourex situdoping of thiophene plasma-treated papers with iodine, conductivity ranging from δ = 4.2E-2 to 4.1 S/cm was obtained. The low relative F/C atomic ratio after TFAA derivatization indicates that no hydroxyl groups were present on the paper surface after the thiophene plasma treatment. [ABSTRACT FROM PUBLISHER]

Corncob is an underutilized agricultural by-product. In this work, corncob was treated with sodium chlorite to remove lignin, and the resulting holocellulose was optionally modified with sodium chloroacetate under alkaline conditions for different time periods to obtain five carboxymethylated corncob holocellulose samples. The derivatization products were investigated by infrared spectroscopy, elemental analysis, carboxyl content tests, and scanning electron microscope analysis. When added at the 1% level (time of carboxymethylation 140 minutes) to an unbleached triploidPopulus tomentosaCarr kraft fiber suspension and made into paper, the tensile index, burst index, and folding endurance were increased by 46.4%, 34.2%, and 397.8%, respectively. The results demonstrated that simultaneous carboxymethylation of both hemicelluloses and cellulose in corncob can be an effective approach to preparing a novel dry-strength additive for paper. [ABSTRACT FROM PUBLISHER]

Microstructural changes in paper after heat-induced inkless eco-printing (HIEP) and pyrolysis productions of paper were investigated by scanning electron microscopy and pyrolysis-gas chromatography/mass spectrometry (Py-G/MS). The results were as follows: (1) When the heat-induced temperature is between 350°C and 600°C, slight scratches are left on the paper surface after scan printing, but click printing leaves obvious concave indentations. Both of these printing methods can create a clear and clean boundary with no significant carbonized microstructure. (2) Experimental studies show that paper undergoes true pyrolysis at 500°C. The simulated printing test shows that the fibers on the paper surface exhibit a yellow discoloration that meets printing requirements. (3) Compared with current laser printing techniques and laser inkless eco-printing (LIEP), HIEP has the advantages of avoiding the de-inking process during paper recycling and preserving paper strength better than LIEP. [ABSTRACT FROM AUTHOR]