Search

In this work, shellac and its crosslinking were studied to produce paper straws for the application of liquid products. Commercial paper straws are not durable for liquid foods due to their hygroscopic nature, and thus, they find it challenging to replace single-use plastics. Shellac is a naturally occurring resin utilized as an adhesive and water-resistant coating over the paper straw. Shellac was cured at 125 °C, 150 °C, 175 °C, and 200 °C, and it was crosslinked in about 210 min, 150 min, 60 min, and 30 min respectively and studied for kinetics. The crosslinking of shellac produced a thermally stable material. Compared to commercial paper straws, these paper shellac straws exhibited high bending stiffness (1356.11 Nmm), tensile strength (13,74 MPa), flexural strength (21.72 MPa), and compression strength (24.99 MPa). Moreover, the paper shellac straws didn't bend in wet conditions under load for up to one day, while the commercial paper straw bends in 8 min. Therefore, paper straws with shellac can replace plastic-based straws for a sustainable future., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Arihant Ahuja reports financial support was provided by the Prime Minister Research Fellowship, Ministry of Education, India. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study developed a multifunctional paper-based freshness antibacterial indicator card by dual-sided coating on conventional filter paper. The indicator coating was composed of anthocyanins from purple cabbage, and polyvinyl alcohol and sodium carboxymethyl cellulose as substrates while the antibacterial coating contained halloysite nanotubes for loaded thyme essential oil and chitosan. FT-IR, XRD, and SEM analyses revealed that the components were well-mixed, and the paper was tightly bound to the coatings through hydrogen bonds. Additionally, the coating effectively filled the porous fiber gaps in the paper, significantly enhancing the mechanical properties of the paper. The tensile strength of the coated paper was enhanced from 14.28 MPa to a range of 42.25-47.71 MPa, and the bending resistance was increased from 0.35 N·mm to a range of 1.72-1.99 N·mm compared to the uncoated paper. The addition of anthocyanins provided excellent sensitivity to pH and ammonia for the indicator card. Furthermore, the coating including halloysite nanotubes for loaded thyme essential oil exhibited antimicrobial resistance against Escherichia coli and Staphylococcus aureus. When used on fresh carp, the antibacterial indicator card not only indicated the freshness of the carp but also extended the best before date of the fish meat by 1-2 days. The indicator exhibited the most pronounced color transformation and optimal freshness indication performance when the mass fraction of anthocyanins was 2 %., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. This work is original research and the data presented in the manuscript has not been published elsewhere., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Due to intrinsic defect of fire hazard security, improving the flame retardant capacity of paper is still insufficient in case of precombustion. Herein, we integrate the flame retardant with flame detection performance on the surface of paper, the restricts of graphene oxide (GO) are overcome between high thermoelectric performance and flexibility. A flexible lamellar thermoelectric composite (GO-LA-HP) is constructed through the co-assembly of GO, ascorbic acid (LA), and phenoxycycloposphazene (HP), lamellar GO-LA-HP avoid GO's toughness decline after modification, but also enhance fire sensitivity and flame resistance. The composite could significantly decrease the temperature rise stage (<150 °C), and trigger the fire-warning within 2 s. The hybrid coating composed of phytic acid/phosphoric acid (PyA/PA) and modified thermoelectric GO-LA-HP becomes excellent compatibility on the surface of the modified paper (GPP). GPP is able to extinguish itself immediately after leaving the fire in the vertical combustion, and display the excellent flame resistance. Furthermore, GPP's alarm signal could be timely generated as little as 3 s of contacting the flame, and the response time can exceed 600 s. According to the structure observation and analysis, the related synergistic fire detection reinforcing and flame-retardant mechanisms are also proposed and clarified., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

To optimize the imbalance between the interfacial bonding and porosity properties of carbon paper (CP) caused by phenol formaldehyde resin (PF) impregnation, and therefore improve the performance of proton exchange membrane fuel cells (PEMFCs), a new approach through cellulose nanofibers grafted with methyl methacrylate (CNFM) as a modified reinforcement and pore-forming agent for PF is investigated. Through suppressing the methylene backbone fracture of CNFM-modified PF during its thermal depolymerization, the interfacial bonding between PF matrix carbon and carbon fibers is enhanced. Compared with unmodified CP, the in-plane resistivity of CNFM-modified CP is reduced by 35.78 %, while the connected porosity increases to 82.26 %, and more homogeneous pore size distribution (PSD) in the range of 20-40 μm is obtained for CNFM-modified CP. Besides, the tensile strength, flexural strength, and air permeability of CNFM-modified CP increase by 72.78 %, 298.4 %, and 103.97 %, respectively. In addition, CNFM-modified CP achieves the peak power density of PEMFCs to 701.81 mW·cm -2 , exhibiting 10.98 % improvement compared with commercial CP (632.39 mW·cm -2 ), evidently achieving an integral promotion of CP and comprehensive performance., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

The monitoring of foodborne bacterial contamination requires simple and convenient biosensors. This work describes a novel paper-based colorimetric biosensor for the rapid and sensitive bacteria detection. The biosensor was constructed via the encapsulation of D-alanyl-D-alanine capped gold nanoparticles (DADA-AuNPs) in a modified paper that was fabricated by the freeze-drying of TEMPO-oxidized cellulose nanofibers/cationic guar gum composite hydrogel-modified filter paper. The results indicated that the size of DADA-AuNPs largely determined the color of their aqueous system and they exhibited light red to dark red as their size increased from around 6 to 36 nm. All these different sized DADA-AuNPs turned into colorless when encountered with either S. aureus or E. coli. In particular, the smaller the DADA-AuNPs size, the faster the discoloration. The encapsulation of DADA-AuNPs into modified paper negligibly changed their responsiveness towards bacteria. In comparison to the original filter paper and oven-dried hydrogel-modified filter paper, the freeze-dried hydrogel-modified paper was demonstrated to be a better substrate for the encapsulation of DADA-AuNPs since they could be loaded with a larger amount of DADA-AuNPs in a faster way and showed a better perceivable color. This work demonstrated a promising paper-based colorimetric biosensor for the facile and rapid detection of bacteria., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The aging of paper seriously threatens the service life of cultural heritage documents. Bacterial cellulose (BC), which has a good fiber aspect ratio and is rich in hydroxyl groups, is suitable for strengthening aged paper. However, a single BC added was not ideal for paper restoration, since only strengthening was not able to resist the persistent acidification of ancient book. In this work, BC was functionalized by 3-aminopropyltriethoxysilane (APTES) to develop the interface bonding with aged paper. Fourier transform infrared (FTIR), X-ray diffraction (XRD), nuclear magnetic resonance (NMR) and elemental analysis identified the successful amino-silanization of BC. The modification parameters were optimized as the concentration of APTES of 5 wt%, the reaction time of 4 h, and the reaction temperature of 80 °C based on a considerable improvement in the strength properties without obvious appearance impact on reinforced papers. Moreover, the pH value of the repaired paper was achieved at 8.03, ensuring the stability of the anti-aging effect. The results confirmed that APTES-BC had great potential applications in ancient books conservation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. All the authors listed have approved the manuscript enclosed., (Copyright © 2024. Published by Elsevier B.V.)

The growing interest in paper-based materials for packaging is driven by their renewable and eco-friendly characteristics. However, their poor barrier performance against water, oil, and gas limits their application in the food packaging industry. In this study, we developed a simple dual-layer coating method to create water- and oil-repellent, gas barrier, antioxidant, and antibacterial paper-based materials using naturally-derived materials, including chitosan (CS), ethyl cellulose (EC), and cascade biorefinery products from green walnut husk (GWHE and CNC). The bottom CS/CNC oil-resistant coating and the top EC/GWHE water-resistant coating were applied to the paper surface. The synergistic effect of these coatings enhances the gas barrier and imparts functional properties to the paper. Compared to uncoated paper, the dual-layer-coated paper demonstrated a 239.1 % increase in tensile index, a higher kit rating value of 12/12, a lower Cobb 60 value of 3.21 mg/m 2 , a 44.0 % decrease in water vapor permeability (WVP), and a 90.7 % reduction in air permeability (AP). Additionally, this coated paper exhibited good antioxidant and antibacterial properties and favorable biodegradability. This study provides novel insights into the valorization of GWH waste and presents a sustainable strategy for producing high-performance paper-based materials for food packaging applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

MOF-199 is considered to be an excellent CO 2 adsorbent owing to its substantial specific surface area, suitable pore structure and abundant sorption sites. However, powdered MOF-199 is prone to agglomeration and has poor recyclability. Herein, we proposed a MOF-199-based adsorbent by combining the MOF synthesis process with traditional papermaking process. Through such a design, MOF-199 particles are adhered on the surface of wood pulp fiber. The sufficient hydroxyl groups and electrostatic forces of cellulose facilitates the homogeneous and tight adhesion of MOF crystals. The optimal MP-4 sample demonstrated a high CO 2 adsorption capacity (1.80 mmol·g --1 at 25 °C) and good CO 2 /N 2 selectivity (30.06). Moreover, the composite sorbent can be easily regenerated. The adsorption mechanism was analyzed by the density functional theory approach. The simulation results showed that the carboxyl functional groups with a large number of oxygen atoms and active metal sites are the key to boost the CO 2 adsorption performance., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Developing plastic/fluorine/silicon-free and degradable water/oil-resistant coatings for paper-based packaging materials to replace disposable plastic products is a very effective way to solve the problem of 'white pollution' or microplastics pollution. A novel water/oil-resistant coating was developed by alkyl ketene dimer (AKD)-based Pickering emulsion and chitosan in this work. Cellulose nanofibrils (CNF) were used as a stabilizing solid for AKD emulsion, with the addition of chitosan as an oil-resistance agent. The coating provides excellent hydrophobicity, water/oil resistance as well as good barrier properties. The water contact angle was as high as 130° and the minimum Cobb60 value was 5.7 g/m 2 , which was attributed to the hydrophobicity of AKD. In addition, the kit rating reached maximum 12/12 at coating weight of 8.26 g/m 2 and the water vapor transmittance rate (WVTR) was reduced to 153.4 g/(m 2 ⋅day) at the coating weight of 10.50 g/m 2 . The tensile strength of the paper was increased from 28.1 to 43.6 MPa after coating. Overall, this coating can effectively improve the performance of paper-based materials, which may play an important role in the process of replacing disposable plastic packaging with paper-based materials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Paper-based test film material is widely used in a variety of test instruments for different applications. The enzyme activity test paper sheet is one of the most popularly used test papers. Here we present a novel fabrication of paper-based enzyme activity test paper without cationic resin added in. The chemical pulping fibers were first beaten to different degrees (from 14.6 to 41.5°SR) with a PFI beater. After that, the fibers were modified with a cationic agent (3-chloro-2-hydroxypropyl trimethyl ammonium chloride) under the system of alkali and water solution. Finally, the test papers were made with the modified fiber by a regular paper former in lab. The results showed that beating is beneficial for the improvement of the cationization reaction which is indicated by the Zeta potential, FTIR and EDS. The main mechanisms involved are the destruction of crystalline zone, increase of free hydroxyl group and defibrillation. This hypothesis was supported by the SEM, XRD and fiber analyzer. Beating under the optimized condition, the wet strength and liquid absorbability of test paper can meet the application requirement, and the test results of enzyme activity are quite close to those of commercial test papers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In recent years, researchers have put much attention on the improvements and upgrades of novel wet strength agent in the papermaking fields, especially in the usage of household paper. Herein, PEI M -KH560 by polyethyleneimine (PEI) and γ-glycidyl ether propyl trimethoxysilane (KH560) was synthesized with five molecular weights (Mw) of PEI at 600, 1800, 10,000, 70,000 and 750,000. Results showed that the molecular weight greatly influenced the physicochemical properties of PEI-KH560, such as the size and thermal stability. The intrinsic cationic charge of PEI-KH560 provided the bonding sites with the paper fibers, forming strengthened fiber-fiber joints. It was shown that the dry, wet strength and hydrophobicity of cellulosic paper sheets were obviously improved. When the m (PEI):m(KH560) is 1:2, the strength of papers after sizing by Mw of PEI at 600 and 1800 is the most obvious, with the dry strength increased by 227.9 % and 187.5 %, and the wet strength increased by 183.8 % and 207.8 %, respectively. The maximum hydrophobicity was found at the PEI 1800 -KH560 with the contact angle value of 130.6°. The resultant environmental-friendly agent (PEI-KH560) obtained in this work provides valuable significance for the preparation of household and food packaging paper., Competing Interests: Declaration of competing interest The authors declare that they have no known competing interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study focuses on enhancing the strength and water stability of paper straws through a novel approach involving a binary emulsion of lignin-based polyurethane and chitosan. Kraft lignin serves as the raw material for synthesizing a blocked waterborne polyurethane, subsequently combined with carboxylated chitosan to form a stable binary emulsion. The resulting emulsion, exhibiting remarkable stability over at least 6 months, is applied to the base paper. Following emulsion application, the paper undergoes torrefaction at 155 °C. This process deblocks isocyanate groups, enabling their reaction with hydroxyl groups on chitosan and fibers, ultimately forming ester bonds. This reaction significantly improves the mechanical strength and hydrophobicity of paper straws. The composite paper straws demonstrate exceptional mechanical properties, including a tensile strength of 47.21 MPa, Young's modulus of 4.33 GPa, and flexural strength of 32.38 MPa. Notably, its water stability is greatly enhanced, with a wet tensile strength of 40.66 MPa, surpassing commercial paper straws by 8 folds. Furthermore, the composite straw achieves complete biodegradability within 120 days, outperforming conventional paper straws in terms of environmental impact. This innovative solution presents a promising and sustainable alternative to plastic straws, addressing the urgent need for eco-friendly products., Competing Interests: Declaration of competing interest There are no conflicts to declare., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Counterfeiting has caused great concern all over the world. What's more, the fluorescent materials play an important role in technological research and development for high-security. In this work, lead-metal-organic framework (Pb-MOF) and perovskite (MAPbBr 3 ) were used in papers to achieving fluorescence counterfeiting. Pb-MOF, as the template or precursor of MAPbBr 3 , were in-situ generated on the surface of cellulose fibers (CFs) to preparing into hand sheets (Pb-MOF@CFs). Through the analysis of experimental results, it was found that ligands, reaction systems, addition sequences of drugs, time, etc. would affect the deposition of Pb-MOF on the surface of CFs. Using CH 3 NH 3 Br (MABr) as the anti-counterfeiting ink to write on Pb-MOF@CFs, the orange writing leaped across the paper, which caused by Pb in Pb-MOF chemically reacting with MABr forming MAPbBr 3 . The orange writing displayed green fluorescence under 365 nm ultraviolet lamp excitation. The orange writing with green fluorescence could be extinguished and reconstructed, which had promise for reuse. In addition, fluorescent security papers (MAPbBr 3 @Pb-MOFs@CFs) were prepared by immersing Pb-MOF@CFs in MABr solution. The fluorescence of MAPbBr 3 @Pb-MOFs@CFs opened when the surface of it was scraped under 365 nm ultraviolet lamp. This unique fluorescence property was very important in improving the security of products. Consequently, the ongoing research on perovskite and MOFs materials is of great significance., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The demand for paper-based packaging materials as an alternative to incumbent disposable petroleum-derived polymers for food packaging applications is ever-growing. However, typical paper-based formats are not suitable for use in unconventional applications due to inherent limitations (e.g., excessive hydrophilicity, lack antimicrobial ability), and accordingly, enabling new capabilities is necessity. Herein, a simple and environmentally friendly strategy was proposed to introduce antimicrobial and hydrophobic functions to cellulose paper through successive chemical grafting of 3-aminopropyltriethoxysilane (APS) and cinnamaldehyde (CA). The results revealed that cellulose paper not only showed long-term antibacterial effect on different bacteria, but also inhibited a wide range of fungi. Encouragingly, the modified paper, which is fluorine-free, displays a high contact angle of 119.7°. Thus, even in the wet state, the modified paper can still maintain good mechanical strength. Meanwhile, the multifunctional composite papers have excellent biocompatibility and biodegradability. Compared with ordinary cellulose paper, multifunctional composite paper can effectively prolong the shelf life of strawberries. Therefore, the multifunctional composite paper represents good application potential as a fruit packaging material., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The abnormal uric acid (UA) level in urine can serve as warning signals of many diseases, such as gout and metabolic cardiovascular diseases. The current methods for detecting UA face limitations of instrument dependence and the requirement for non-invasiveness, making it challenging to fulfill the need for home-based application. In this study, we designed an aptasensor that combined UA-specific transcriptional regulation and a fluorescent RNA aptamer for convenient urinary UA testing. The concentration of UA can be translated into the intensity of fluorescent signals. The aptasensor showed higher sensitivity and more robust anti-interference performance. UA levels in the urine of different volunteers could be accurately tested using this method. In addition, a paper-based aptasensor for UA self-testing was manufactured, in which the urinary UA levels could be determined using a smartphone-based colorimetric approach. This work not only demonstrates a new approach for the design of disease-associated aptasensor, but also offers promising ideas for home-based detection of UA., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Cellulose fibers(CFs)-based electrode materials are of considerable interest for future wearable electronic devices due to excellent flexibility and strength, and hydrophilicity. The effective introduction of electrode materials into CFs is essential for flexible supercapaciotors(SCs). A tunable electrochemical performance of conductive polymers for poly(3,4-ethylenedioxythiophene)(PEDOT) has been aroused great interests. Herein, we design its electrochemical process via sodium anthraquinone-2-sulfonate(AQS) as dopant and electrolyte additive to construct active electrode interior and interface. As a result, the PEDOT@CFs electrode exhibits great increase of doping level from 0.16 to 0.29, conductivity from 353.46 to 626.15 S m -1 , and specific capacitance from 140.22 to 1211.57 F g -1 at a current density of 0.2 A g -1 . Furthermore, the PEDOT:AQS@CFs electrode possess excellent cyclic stability (96.01 %) after 1000 cycles. The work reveals the mechanism of AQS as dopant and electrolyte additive, and provides a new perspective for application of PEDOT in energy storage field., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In order to reduce the quality loss of citrus and extend its storage time after harvest, it is essential to develop coated kraft papers with antibacterial and fresh-keeping properties. In this study, cinnamon essential oil (CEO)/soybean protein isolate (SPI) microcapsules were prepared by the coagulation method, and their properties were optimized. Then, the microcapsules were added to konjac glucomannan (KGM) as a coating solution to enhance the physical, and chemical properties of kraft paper by a coating method. The release behavior of CEO, tensile properties, antibacterial properties and preservation effects of the paper were investigated. The results show that when the ratio of wall to core was 7:3, the highest encapsulation rate was 92.20 ± 0.43 %. The coating treatment significantly reduced the oxygen and water vapor transmission rates of kraft paper. The shelf life of citrus treated with coated Kraft was extended by >10 days. Thus, the CEO/SPI microencapsulation and KGM coating could improve the properties of kraft paper and have the potential for citrus preservation., Competing Interests: Declaration of competing interest We declare that this manuscript as original and there are not any financial or other conflicts of interests. As the corresponding author, I confirmed that the manuscript has been read and approved for submission by all named authors who have contributed significantly., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Sustainable strategies to improve the water resistance of cellulose paper are actively sought. In this work, polymeric microspheres (PMs), prepared through emulsion polymerization of cellulose nanofibers stabilized rubber seed oil-derived monomer, were investigated as coatings on corrugated medium paper (CMP). After infiltrating porous paper with PMs, the water-resistant corrugated papers (WRCP n ) with enhanced mechanical properties were obtained. When 30 wt% PMs were introduced, WRCP 30 turned out to be highly compacted with an increased water contact angle of 106.3° and a low water vapor transmission rate of 81 g/(m 2 d) at 23 °C. Meanwhile, the tensile strength of WRCP 30 increased to 22.2 MPa, a 4-fold increase from CMP. When tested in a well-hydrated state, 71% of its mechanical strength in the dry state was maintained. Even with a low content of 10 wt% PMs, WRCP 10 also exhibited stable tensile strength and water wettability during the cyclic soaking-drying process. Thus, the plant oil based sustainable emulsion polymers provide a convenient route for enhancing the overall performance of cellulose paper., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Development of green packaging materials is essential to replace traditional plastics in fresh agricultural products preservation. Herein, a coated paper was designed by applying chitosan-based composite coating on paper substrate through a facile automatic coating method. The hydroxypropyl trimethyl ammonium chloride chitosan (HACC) was obtained by direct quaternization via the introduction of hydroxypropyl trimethyl ammonium chloride into the amino group of chitosan, then mixed with polyvinyl alcohol (PVA) to prepare the HACC/PVA coating. Accordingly, the key performance of coated paper were improved ascribed to the synergy effect of HACC/PVA coating and paper substrate. In particular, the minimum oxygen permeability of the coated paper could reach to 0.87 × 10 -13  cm 3 ·cm/cm 2 ·s·Pa, and the optimum water vapor permeability and tensile strength of HACC/PVA coated paper was 0.75 × 10 -12  g·cm/cm 2 ·s·Pa and 6.88 kN/m, respectively. The coated paper used as packaging material not only reduced weight loss ratio of strawberry and greengrocery, but also exhibited lower chromatic aberration and better sensory evaluation, indicating a favorable effect on fruit and vegetable storage. Taken together, the designed eco-friendly coated paper has shown tremendous potential for green and biodegradable packaging material in agricultural products preservation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Novel eco-friendly strength agent has inspired much attention of researchers. Herein, the PEI-KH560 prepared by PEI (polyethyleneimine) and KH560 (γ-glycidyl ether propyl trimethoxysilane) was added in the pulp suspension to enhance the paper performance. The results showed that the m(PEI):m(KH560) ratio and PEI's molecular weight were closely related with the paper strength and hydrophobicity. The SEM morphology of paper surface showed that the fiber-fiber crosslinking reached the tightest, at the optimal m(PEI):m(KH560) ratio and PEI's molecular weight. The results showed that when the M w (molecular weight) of PEI was 10,000 and the m(PEI):m(KH560) ratio was 1:2, the PEI-KH560 presented the best strengthening performance on the paper strength and hydrophobicity. Dry tensile index and wet tensile index could reach 29.9 N·m/g and 1.37 N·m/g after adding the PEI 10000 -KH560 in pulp suspension before the paper formation. Further, the effect of process conditions (temperature, time, the addition amount, and pulp concentration) on the strength and hydrophobicity of paper network structure was investigated, after adding PEI-KH560 into the pulp suspension. It was of great significance for studying the mechanism between the chemical structures of PEI-KH560 and paper performance, which provided valuable theoretical practice on the preparation of novel strength agent., Competing Interests: Declaration of competing interest The authors declare that they have no known competing interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

User-friendly in-field sensing protocol is crucial for the effective tracing of intended analytes under less-developed countries or resources-limited environments. Nevertheless, existing sensing strategies require professional technicians and expensive laboratory-based instrumentations, which are not capable for point-of-care on-site analyses. To address this issue, artificial intelligence handheld sensor has been designed for direct reading of Ni 2+ and EDTA in food samples. The sensing platform incorporates smartphone with machine learning-driven application, 3D-printed handheld device, and cellulose paper microfluidic chip stained with ratiometric red-green-emission carbon dots (CDs). Intriguingly, Ni 2+ introduction makes green fluorescent (FL) of CDs glow but red FL fade because of the coordination of Ni 2+ with CDs verified by density functional theory (DFT), concurrently manifesting continuous FL colour transition from red to green. Subsequent addition of EDTA renders FL of CDs-Ni 2+ recover owing to the capture of Ni 2+ from CDs by EDTA based on strong chelation effect of EDTA on Ni 2+ confirmed via DFT, accompanying with a noticeable colour returning from green to red. Inspired by above FL phenomena, CDs-based cellulose paper microfluidic chips are first fabricated to facilitate point-of-care testing of Ni 2+ and EDTA. Designed fully-automatic handheld sensor is utilized to directly output Ni 2+ and EDTA concentration in water, milk, spinach, bread, and shampoo based on wide linear ranges of 0-48 μM and 0-96 μM, and low limits of detection of 0.274 μM and 0.624 μM, respectively. The proposed protocol allows for speedy straightforward on-site determination of target analytes, which will trigger the development of automated and intelligent sensors in near future., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Shaomin Shuang reports that funding was provided by National Natural Science Foundation of China. Bianxiang Zhang reports that funding was provided by Central Guidance Local Science and Technology Development Fund Project. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study focused on the morphology regulation of nanocelluloses (NCs) aiming at preparing NCs with the controllable properties. NCs with rod-shaped, spherical, and rod-shaped and spherical composite structures were prepared from waste paper by a green enzymatic hydrolysis. The critical enzyme concentration for the transition of NCs from one morphology to another was explored. Several analytical methods, including TGA, XRD, SEM, TEM, DSC and WCA, were employed to characterize the prepared NCs. The results showed that with the cellulase enzyme concentration lower than 6 μ/ml or higher than 30 μ/ml, the prepared NCs had a single rod-shaped or spherical structure. When the cellulase concentration was between 6 and 30 μ/ml, the prepared NCs had a composite morphology of rods and spheres. Besides, NCs with a composite morphology dominated by rod-like or spherical structures had a higher thermal stability. Moreover, NCs prepared with cellulase enzyme concentration of 6 and 35 μ/ml had the highest and lowest crystallinity of 81.7 % and 59.3 %, respectively. Hence, this work achieved the morphology and property regulation of NCs by a green method which expanded the application scope of NCs and realized the high value utilization of waste paper., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Anionic cellulose nanofibers (CNFs) were used to stabilize emulsions that combined water-soluble (and oil-soluble), strongly antioxidant extracts with a water-immiscible, notably antimicrobial essential oil. Specifically, the radical scavenging activity was primarily provided by aqueous extracts from olive fruit (Olea europaea L.), while the antimicrobial effects owed eminently to thyme oil (Thymus vulgaris L.). The resulting emulsions were highly viscous at low shear rate (4.4 Pa·s) and displayed yield stress. The addition of edible salts decreased the yield stress, the apparent viscosity and the droplet size, to the detriment of stability at ionic strengths above 50 mM. Once characterized, the antioxidant and antimicrobial emulsions were applied on packaging-grade paper. Coated paper sheets inhibited the growth of Listeria monocytogenes, a common foodborne pathogen, and acted as antioxidant emitters. In this sense, the release to food simulants A (ethanol 10 vol%), B (acetic acid 3 wt%), and C (ethanol 20 vol%) was assessed. A 24-hour exposure of 0.01 m 2 of coated paper to 0.1 L of these hydrophilic simulants achieved inhibition levels of the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) in the 15-29 % range. All considered, the bioactive properties of thyme essential oil towards lipophilic food products can be complemented with the antioxidant activity of aqueous olive extracts towards hydrophilic systems, resulting in a versatile combination for active food packaging., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)