Abstract To reduce the exposure risk of potentially harmful cigarette smoke, the precise design of fiber raw materials is key to modifying pyrolysis product distributions in cigarette paper. This study investigates the effects of pulp/wood blending ratios on the physical properties, chemical composition, and pyrolysis behavior of cigarette paper. Results indicate that the pulp blending ratio reconstructs the chemical microenvironment – particularly the lignin/hemicellulose distribution – thereby inducing a directional shift in the pyrolysis pathway. At 900 °C, the total relative abundance of fused-ring aromatic compounds and benzenes decreased from 55.07 % (pure hemp pulp, S1) to 43.87 % (pure softwood pulp, S7), demonstrating that wood pulp incorporation significantly regulates product distribution. This work elucidates the intrinsic relationship among fiber composition, chemical microenvironment, pyrolysis behavior, and products distribution, providing a theoretical basis for designing cigarette paper with tailored pyrolysis product profiles. The results represent compositional trends under pyrolytic conditions and require further validation under standardized smoking conditions for extrapolation to actual cigarette smoke.
This study aims to comprehensively evaluate the effects of coating processes employing lignin-reinforced nanocellulose suspensions, derived from various types of waste paper, on the functional and physicochemical properties of packaging papers. In particular, the study focuses on elucidating how the incorporation of lignin within nanocellulose-based coating systems affects key performance characteristics, including mechanical strength, barrier performance, surface properties, and overall paper quality. The results revealed that physical, mechanical, optical, and barrier properties of the papers were significantly influenced by the coating formulation. Papers coated with cellulose nanofiber/lignin (CNF/L) and cellulose nanocrystal/lignin (CNC/L) suspensions exhibited increased thickness and grammage relative to both uncoated and water-coated counterparts. Following the application of nanocellulose/lignin (NC/L) suspensions, a decline in tensile and tear indices was observed, whereas the burst index demonstrated a notable enhancement. Evaluation of optical properties revealed that, except for opacity, all measured optical parameters improved upon coating with CNF- and CNC-based suspensions. In terms of barrier performance, NC-based coatings resulted in higher water absorption values while simultaneously reducing air permeability compared to uncoated papers. To sum up, this study suggests that leveraging CNF and CNC can enhance the quality of low-grammage packaging papers, potentially opening new avenues for their applications.
Abstract LED lighting exhibits a pronounced short-wavelength peak that can contribute to visual discomfort during near-work tasks. This study evaluates LUTI, a lutein-pigmented paper, designed to selectively attenuate blue-light reflectance while maintaining colour neutrality and material stability. Spectral, colorimetric and ageing measurements demonstrate that LUTI reduces reflectance in the 400–480 nm region with minimal chromatic shift and acceptable stability. The findings support the concept of natural-pigment functionalization of paper for improving visual ergonomics in LED-illuminated environments.
The valorization of hemicellulose represents a sustainable pathway toward bio-based papermaking additives. In this study, hemicellulose was isolated from the black liquor of potassium hydroxide pulping of corn stalk. The recovered hemicellulose, which was predominantly xylan (89.3 % xylose), exhibited poor water solubility (2 %) and low nitrogen content (1.46 %), limiting its direct application as a wet-end additive. To overcome these limitations, the hemicellulose was cationized using (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC) under alkaline conditions. The cationization reaction was optimized by varying temperature, CHPTAC-to-hemicellulose molar ratio, and NaOH-to-CHPTAC molar ratio. Under optimal conditions, the cationic hemicellulose achieved a degree of substitution of 0.16 and a yield of 58.75 %. The cationic hemicellulose exhibited significantly improved water solubility (20 %) and increased nitrogen content (1.99 %). When applied to recycled pulp at doses up to 1.5 wt%, the cationic hemicellulose improved tensile, burst and tear indices. Furthermore, when used as a retention aid for precipitated calcium carbonate (PCC) at 10 % filler loading, cationic hemicellulose achieved an ash content of 8.38 % while maintaining superior mechanical properties compared to cationic starch. These findings demonstrate that cationized hemicellulose from KOH pulping black liquor is an effective, renewable wet-end additive for papermaking applications.
Inkjet printing has become an important technology for functional patterning in packaging, electronics, and security applications. In ink formulations, the binder plays a key role in determining rheological behavior and jetting stability, which directly affects print fidelity. In this study, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (TOCNF) were employed as a sustainable binder for water-based inks due to their shear-thinning behavior and film-forming capability. Carbon quantum dots (CQDs) were incorporated into the TOCNF system to explore the feasibility of functional formulations for fluorescent anti-counterfeiting. Rheological analysis showed that the inks exhibited pronounced shear-thinning behavior and rapid viscosity recovery in the three-interval thixotropy test, enabling stable droplet formation during inkjet printing. Optimal jetting stability and printing resolution were obtained at a TOCNF concentration of 0.5 |wt% and an oxidation level of 10 mmol/g NaClO. The CQD-loaded inks produced high-resolution printed patterns with stable fluorescence, indicating the potential of TOCNF-based formulations for fluorescent anti-counterfeiting applications in packaging.
Plant fibers are the core raw materials of traditional East Asian handmade papers. For their identification, microscopic observation has been conventionally conducted relying on fiber staining combined with optical microscopy. Comparatively, polarized light microscopy (PLM) has long been underutilized, especially in the study of ancient East Asian paper relics. Thus, this study aims to evaluate the feasibility of PLM in characterizing fiber optical properties and identifying morphological features, which can be used to distinguish bast fibers in traditional Chinese handmade paper production. As a result, the differences in microfibril angle (MFA) and the effects of alkali treatment on the samples suggest that color changes in the sign of elongation (SE) can serve as indicators for fiber evaluation and characterization, though nuance differences await further exploration. Methodologically, the cross-polarized light (CPL) mode detects optical characteristics (SE and Herzog tests), while the single-polarized light (SPL) mode captures morphological details. This combined approach can effectively distinguish different papermaking bast fibers, offering a micro-destructive technique for identifying plant fibers in East Asian handmade papers and fibrous relics in antiquity.
This study explores the potential to reduce the use of polyamidoamine-epichlorohydrin (PAE) wet-strength additives in tissue paper by replacing fully bleached fibers with oxygen delignified softwood pulps. Laboratory isotropic 20 g/m2 hand sheets were produced from commercial fully bleached pulp (reference pulp), unbleached kraft pulp, and oxygen delignified pulps with varying lignin contents and fiber charge levels. The impact of PAE, alone and in combination with carboxymethylcellulose (CMC) was evaluated for both unrefined and PFI refined pulps. The unbleached kraft pulps and oxygen delignified pulps characterized by different lignin contents and total fiber charge levels, exhibited significantly higher fiber swelling and enhanced wet tensile strength compared to the fully bleached pulp. Notably, the use of oxygen delignified pulps enabled up to a five-fold reduction in PAE requirement while maintaining comparable wet tensile strength. Beyond performance gains, these pulps offer sustainability advantages by reducing the extent of delignification and eliminating the need for full bleaching. The findings highlight the role of fiber chemistry - particularly lignin content and fiber charge - in wet strength development, and suggest a promising pathway toward more resource-efficient tissue products.
Historic paper relics are crucial for preserving cultural heritage, but acid-catalyzed cellulose hydrolysis causes severe deterioration. Traditional alkaline deacidification struggles with long-term protection, especially for highly acidified papers. This study developed stable Ca(OH)2 nanoparticles suspensions (hydrodynamic diameter 100-200 nm, polydispersity index 0.17) by reacting calcium methoxide with water in 95 % ethanol under ultrasonic treatment. The acquired nanoparticle suspensions remained stable for 70 days. When applied to deacidified acidic paper, it raised the pH from 4.2 to 9.0, and the pH maintained at similar to 7.3 after one-week artificial aging under the constant conditions (80 degrees C, and 65 % relative humidity). X-ray diffraction revealed the transformation of calcium compounds during deacidification, while SEM-EDS/AFM confirmed uniform calcium distribution forming protective surface layers. Cross-sectional analysis via SEM showed nanoparticles filling paper microfiber gaps without altering structural topography. This nanoparticle-based approach effectively neutralizes acidity while preserving paper integrity, offering a promising solution for long-term conservation of historical documents.
A shear loading test was performed to obtain the edgewise compressive properties of two 1-mm-thick flat cardboard samples whose length coincided with the machine and cross directions. To determine the optimum configuration of the sample, the gauge length, defined as the distance between the inner edges of the tabs adhered to the ends of the sample, was varied from 2 to 30 mm, the optimum gauge length was determined to be 12 mm. The compressive stress-strain relationship was subsequently obtained using the sample with this optimum configuration, and the Young's modulus, proportional limit stress, compressive strength, and Poisson's ratio were determined. In addition, these properties were compared with those obtained from a tension test conducted independently of the compression test. Based on the results obtained in this study, the shear loading test was effective in obtaining several edgewise compressive properties of cardboard when the sample configuration was appropriately designed, despite several issues that should be solved in the future.
In this study, the correlation between optical density (D) and color difference (Delta E ab) was investigated through the variation of ink transfer (Delta G) efficiency among the CMYK process inks and RGB overprints (R = Y/M, G = Y/C, and B = M/C). The mathematical regression model D = D (max)(1-e( -k.Delta G) ) and D = D max(1-e(-k.t)) were used to describe the relationship between optical density (D) and ink transfer amount, and ink film thickness (t) and for cyan, magenta, yellow, and black inks, respectively. Statistical analysis (ANOVA, p < 0.001) confirmed the strong correlation between ink transfer and ink film thickness with optical density (R-2 > 0.90). Correlation between optical density and color difference Delta E ab is the second-order polynomial (y = y(0 )+ b (1) x + b (2)x(2)) regression model. The findings emphasize the importance of density control in offset printing to maintain consistent color appearance and minimize Delta E-ab across production runs. The mathematical regression models of ink trapping (IT) as a function of the secondary ink volume (IT = ITmax(1-e (-k.Vink))). The results demonstrate that optical density and color difference are closely governed by ink transfer behavior, and the new trapping model provides a reliable tool for predicting color deviation in multicolor offset printing.
Paper documents serve as vital archives preserving human civilization, yet acidification remains the primary factor causing their deterioration. To protect these cultural treasures from acid damage, researchers typically apply alkaline substances through non-aqueous or aqueous solvent systems in batches of paper. However, these methods may cause environmental pollution or demonstrate low processing efficiency. This study proposes a novel approach: utilizing calcium oxide to deacidify acidic paper through air circulation exposure. Experimental results show that treated paper samples achieved stable pH values of 8.20-8.80 with uniform deacidification. Both the overall pH and alkali storage levels met cultural heritage protection standards (the pH values are between 8.00 and 8.50, and the alkali reserve is not less than 0.6 wt% CaCO3 equivalent). Microscopically, this process enables deep calcium carbonate deposition while maintaining intact fiber structures. Notably, the treated samples showed negligible impacts on tensile strength, tear index, folding endurance, and zero-distance tensile strength, with minimal visible changes in appearance.
Use of microfibrillated cellulose (MFC) from recycled sources gain more and more interests in paper industry, whose prevailing direction is to increase the incorporation rate of recycled fibers without decreasing paper quality, increasing the cost or toxicity of current processes. This study proposes a better comprehension in the phenomenon involved during the fibrillation of recycled fibers. MFC were prepared from two recycled paper grades, Corrugated Cardboard (CC) and Recycled Liner (RL), and from virgin lignin-rich unbleached Kraft pulp (VKP). These materials were compared with a commercial MFC from virgin bleached pulp. Morphological analyses and AFM images evidenced highly fibrillated materials after ultra-grinding. Tensile and air permeability tests on nanopapers revealed better performance for MFC from virgin resources, even compared to recycled pulp devoid of mineral fillers. Ozonation as a pretreatment showed limited effectiveness for fibrillation. Incorporation of MFC from recycled sources (RMFC) into RL significantly enhanced mechanical properties: +39 % in Young's modulus and +44 % in tensile strength. Despite RFMC exhibited lower intrinsic performance than MFC from VKP, its reinforcement efficiency brought to RL was similar. Sheet porosity, assessed through air permeability and roughness, further decreased with RMFC addition. Finally, RMFC proved a sustainable alternative to virgin MFC.
Polypropylene (PP) is a poorly degradable material, mainly used as an air filter, and causes environmental pollution; therefore, an eco-friendly filter material must be developed. In this study, bamboo pulp obtained via organosolv pulping was mixed with a low-melting-point polyester and activated carbon to produce a filter basepaper. The as-produced basepaper was an isotropic material with a similar tensile index in both machine and cross directions and could filter 100 % of paraffin oil with particles >5 mu m. This basepaper exhibited filtration efficiencies of up to 88 % and 97.7 % for >1.0-3.0 and 3.0-5.0 mu m A2 dust particles, respectively, exceeding those of commercial spunbond materials and demonstrating excellent filtration performance. The corresponding quality factor (QF) for the fabricated basepapers showed significant improvement, reaching up to 91 % higher than that of commercial spunbond materials. These results confirm that the fabricated basepaper has great potential as a substrate and support for eco-friendly filters.
The effect of beating on the paper performance of bagasse cellulose fibers was investigated by analyzing changes in morphological parameters (fiber length and fines content), physical properties (tensile strength, breaking length, and tensile force), water retention value (WRV), cellulose crystalline structure, and pore structure of the fibers. The results indicate that the fines content increased by 4.98 % at 80 degrees SR compared with the unbeated sample. Tensile strength, breaking length, and tensile force increased with the beating degree. WRV also increased with beating, showing a rise of 62.89 % after the first refining stage. In contrast, the cellulose crystallinity first increased and then decreased with beating intensity, being 3.1 % lower at 80 degrees SR compared with that at 13 degrees SR. FTIR spectra indicated no significant changes in the functional groups of bagasse cellulose during the beating process. With increasing beating intensity, the pore size distribution gradually shifted toward larger pores, leading to an increase in the average pore volume.
Kraft lignin is a promising biopolymer for product diversification in the pulp and paper industry and integrated biorefinery concepts. This study evaluated the effect of white liquor sulfidity (0-40 %) on Eucalyptus spp. kraft lignin recovered by acid precipitation (CO2 and HCl). The recovered lignins were characterized in terms of elemental composition, thermal behavior, and chemical structure. While sulfidity had a limited impact on the overall thermal stability and decomposition profiles, it strongly affected pulping performance, including total yield, H-factor, and cooking severity. Notably, the sulfur and sodium contents of the recovered lignin varied systematically with sulfidity, reflecting changes in the delignification pathway and black liquor chemistry. Higher sulfidity enhanced sulfide-assisted lignin fragmentation, leading to the incorporation of sulfur-containing functionalities (e.g., thiols and mercaptans) and a reduced dependence on sodium for lignin solubility. The outcomes provided insights into how sulfidity can influence lignin properties with implications for its subsequent use in advanced materials applications.
This study addresses the high cost of imported flax pulp (FP) in fine cigarette paper production. It was found that the key difference between bleached hardwood kraft pulp (HBKP) and FP lies in their hemicellulose components. Consequently, commercial HBKP was treated with xylanase under optimized conditions, reducing its xylose content by up to 18.5 %. Based on this process, the same enzymatic treatment was applied to the mixed pulp in cigarette paper production lines, yielding even better results. Enzyme-treated bleached hardwood kraft pulp (EHBKP) was used to partially replace FP (0-50 %) in cigarette papermaking. The effects on the physical properties and pyrolysis characteristics of the resulting paper were comparatively studied. The results showed that when EHBKP replaced 10-50 % of FP, the tensile strength of the paper increased by up to 15.6 %, while the tear index decreased by only 10.9 %. Py-GC/MS analysis revealed that when EHBKP replaced 10 % of FP in cigarette paper production, benzene compounds generated from paper pyrolysis at 900 degrees C decreased by 23.7 %, and phenolic compounds continued to decrease with increasing replacement levels. In conclusion, replacing 10-20 % of FP with EHBKP significantly reduces harmful pyrolysis products while maintaining essential physical properties, combustion performance, and paper thermal stability.
Paper relics tend to deteriorate and become brittle during long-term preservation. Cellulose as a major component of paper is commonly utilized for reinforcing paper materials. In this study, the solutions of cellulose were prepared using three different solvents: 1-butyl-3-methylimidazolium chloride ([Bmim]Cl),1-butyl-3-methylimidazolium acetate ([Bmim]Ac) and N-methylmorpholine-N-oxide hydrate (NMMO/H2O). A dyeing and labeling method is employed to demonstrate that these solutions could effectively penetrate into the interior of the paper and form regenerated cellulose. Scanning electron microscopy (SEM) analysis revealed the formation of a continuous cellulose layer on the surface of the treated paper samples. All samples were subjected to the same reinforcement procedure followed by accelerated aging tests. The mechanical properties, whiteness, and chromatic aberration of the samples were evaluated. Results indicated that the solution of cellulose dissolved in [Bmim]Ac achieved the most favorable balance between reinforcement efficacy and preservation of the original paper properties, when the amount of cellulose added was 6 g/m2, the tensile index increased by 26.16 %, with a chromatic aberration value of 1.86 observed before and after reinforcement. That study provides a new approach for the application of cellulose solutions in the conservation of paper-based cultural heritage.
With currently enormous and growing demand for portable electronic devices, flexible electrodes have garnered significant research attention. Cellulose fibers with low-cost, environmentally friendly, renewable and flexible properties have become a promising trend for flexible substrates. Exploring the influence of different plant fibers on various properties of electrodes is of positive significance to the selection of raw materials for flexible electrodes. However, the existing work mainly utilized plant fibers as support material, with limited exploration of their effects on the electrical and electrochemical properties of flexible electrodes. Herein, we successfully fabricated self-supporting polypyrrole (PPy) cellulose-based flexible electrodes through in situ polymerization of pyrrole on the surface of different types of plant fibers with liquid phase redox combined with wet papermaking process. Among all tested plant fibers, the bamboo fiber-based self-supporting flexible electrode with a PPy loading of 30 g m-2 exhibited excellent conductivity (4.02 S cm-1) and outstanding electrochemical performance, delivering an areal capacitance of 1,490 mF cm-2 at 5 mA cm-2, benefiting from bamboo fiber's unique morphology. The development of high performance flexible electrode with bamboo fiber not only offers a green and cost-effective approach but also expands the application potential of plant fibers in flexible electronic devices.
Blending wood species can combine complementary fiber attributes in a single pulp. This study evaluated kraft pulping of Pinus sp. and Eucalyptus sp. chip mixtures and the bleachability of the resulting pulp. Pulping was performed to reach Kappa 20 +/- 1 using eucalypt/pine blends at 90/10, 80/20, 70/30, and 60/40 (oven-dry mass). A 100 % eucalyptus pulp served as the Reference. All pulps were bleached with an ECF sequence. As pine proportion increased, the H-factor rose from 481 (Reference) to 1,170 at 40 % pine. Brown pulp viscosity showed a decreasing trend with increasing long fiber content. Bleaching reacted in such a way that pulps with higher long fiber content and lower bleachability required higher active chlorine loads. Overall, kraft pulping of these mixtures proved technically feasible. However, these operational trade-offs should be weighed against potential property gains from longer fibers, so that chip-mix strategies can be tuned to balance product performance with pulping and bleaching.
Pineapple leaves, often found as waste in North Tapanuli District, Sipahutar District, contain high levels of cellulose, making them a potential source for extracting cellulose nanocrystals (CNC). This study employs the acid hydrolysis method, followed by ultrasonication, to produce CNC, a process known for its simplicity and effectiveness in removing amorphous cellulose. The Fourier transform infrared spectroscopy (FTIR) analysis at a wavenumber of 1,358 cm-1, associated with S=O vibrations, indicates esterification during hydrolysis. Transmission electron microscopy (TEM) reveals that the extracted CNCs exhibit a rod-like structure with a diameter of 5.18 +/- 1.61 nm. X-ray diffraction (XRD) results show a crystallinity index of 78 % and a crystal size of 2.35 nm. The CNCs were incorporated into used newspaper pulp at varying concentrations (0, 1.5, 3, 5, and 8 |wt%). The findings demonstrate that CNC addition enhances the mechanical properties of the paper, including grammage, tensile strength, tear index, and crack index, primarily due to hydrogen bonding interactions between CNCs and pulp fibers. The optimal improvement was observed with a 5 | wt% CNC addition, significantly increasing tensile strength, tear index, and crack index of the recycled paper.
