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Poly(p-phenylene benzobisoxazole) (PBO) fibre-based specialty paper has become a promising candidate for high-performance insulating materials due to the remarkable properties of PBO fibres. However, the porous structure and poor interfacial interaction of PBO paper seriously weaken its mechanical strength and greatly limit its practical application. Herein, proposed for the first time, a homogeneous reinforcement strategy is developed to regulate the microstructure of PBO paper and efficiently enhance its overall properties. For this reason, flexible ortho-hydroxy polyamic acid (HPAA) was first synthesized and used to impregnate PBO paper. Subsequently, HPAA was thermally converted into a benzoxazole-containing resin, manifesting excellent interfacial compatibility with PBO paper. As a result, the compact structure and solid interface endow the composite paper with impressive performance. The tensile strength, modulus, and electrical breakdown strength of the composite paper are 116.86 MPa, 5.47 GPa, and 63.7 kV mm−1, respectively, increasing by 33.1, 8.1, and 1.1 times compared with those parameters of the original paper (3.43 MPa, 0.60 GPa, and 30.5 kV mm−1). Moreover, the composite paper also exhibits an ultra-low dielectric constant and loss tangent (1.6 and 0.004 at 106 Hz, respectively), as well as superhigh thermal stability (maximum decomposition temperature, Tmax ≈ 600 °C) due to the elaborate design of the structure. Thus, the mechanical strength has been successfully integrated with the outstanding insulation and thermal properties, rendering the lightweight PBO composite paper promising in the field of high-temperature and high-voltage electrical insulation. [ABSTRACT FROM AUTHOR]

Paper-based packaging materials are generally assembled using adhesives formulated with oil-based polymers. These adhesives make the recyclability of the materials more complex and may be the source of material contamination by mineral oil. In view of developing an adhesive-free process, the potential of ultrasonic compression was investigated in this study. 100% lignocellulosic papers were assembled using an ultrasonic welder dedicated to thermoplastic polymers. For papers containing lignin, the measured peeling strengths were equivalent to those achieved by hot-melt gluing, provided that the water content of papers was well adjusted. At the interface between bonded papers, the fiber network was dense and rather continuous. SEM examinations, 3D X-ray microtomography images, and temperature measurements suggested that the development of adhesion originated to a large extent from a thermoplastic welding mechanism: wood fiber polymers passed their glass transition temperatures, creeped and formed a matrix that coated fibers. Thus, ultrasonic welding appears as an efficient adhesive-free technique for assembling papers that are used in a broad range of packaging applications. [ABSTRACT FROM AUTHOR]

The interface structure greatly affects the material surface wettability. Polyphenylene sulfide (PPS) fiber paper was modified via regulation of thermally induced phase separation process to obtain interfacial nanofiber network-like morphology, which obeyed nucleate-growth mechanism with the PPS resin on the fiber surface as the core. PPS nanofiber network layer with rough concave surface feature endowed the modified PPS fiber paper with stable superhydrophobic properties, and it showed excellent oil absorption and oil/water separation performance. The separation efficiency of using P-2 paper to separate the five oil/water mixtures listed in this paper were more than 99.99%, and the kerosene flux was more than 7350 L m−2 h−1 driven by gravity. Excellent hydrophobicity and cycling performance made PPS fiber paper with excellent reusability. In addition, the PPS fiber paper had also been proved to be used in strong acid–base and organic solvents for a long time. This work provided a PPS fiber paper for oil/water separation with simple preparation process, which was expected to be produced in large scale and applied in industrial field. [ABSTRACT FROM AUTHOR]

This work brings in an eco-friendly, smart integrated miniaturized sensor system to determine the temperature of aqueous solution and soil in a more affordable way to yield quality farming, small-scale agricultural farming, greenhouse farming, domestic gardening, and hydroponics. Carbon-Graphite hybrid electrode-based planar disposable sensor strip is used for sensing the temperature over a range of 27 to 50°C. The temperature sensor element is compared to four distinct structures, and the meander geometrical structure is deduced as a result. The temperature sensing element is fabricated utilizing a prudent, efficacious, and inexpensive microfabrication methodology of screen printing. The temperature and resistance characteristics are plotted for the carbon-graphite electrode on PET and paper. The temperature coefficient of resistance is determined to be 1%/°C for PET and 0.8%/°C paper substrate in soil. Test experiment was carried out in water, oven and on field to find out the characteristic equation of study. The temperature sensor strip is integrated with a Wi-Fi SoC-assisted nodeMCU processor that is used in IoT platforms. An app is created using MIT app inventor user interface and is launched on an android smartphone. The app gives the suitable temperature range for sowing seed and germination of the plant growth information. The instantaneous temperature of soil or water is measured, and status information for plant cultivation is also provided by the app. [ABSTRACT FROM AUTHOR]

The flame resistance of kraft paper was greatly modified by an eco-friendly, phosphorus-containing and reactive flame retardant, ammonium phosphite, which was grafted on kraft paper via pad-bake method. The results showed that the limiting oxygen index of treated kraft paper could increase from 19.1 to 48.2%. The results of vertical flammability tests imply that the char length of treated sample decreased from 210 to 45 mm. Thermogravimetry analysis showed that treated kraft paper had the lower initial decomposition temperature and more residues than control sample. Thermogravimetry analysis/infrared spectrometry indicated that the flammable volatile species of treated kraft paper reduced obviously compared with that of control sample. Fourier transform infrared spectroscopy suggested that ammonium phosphite was grafted on the cellulose molecules by P-O-C covalent bonds and the flame retardant is reactive in condensed phase. Scanning electron microscopy showed that the modification had little effect on the surface of kraft paper and the residual carbonized frame of treated kraft paper retained the fiber shape after combustion. EDX results showed that the flame retardant introduced a large amount of phosphorus and nitrogen into kraft paper. X-ray diffraction indicated that the modification did not significantly affect the crystal structure of kraft paper. And the strength of kraft papers slightly declined after the modification, but it still remained well. [ABSTRACT FROM AUTHOR]

Starch is one of the most popular biodegradable polymers in nature, which is gaining increasing attention because of its abundant availability and low cost. However, starch film itself is very brittle and its barrier property is poor for many applications. Polyvinyl alcohol (PVA), a versatile polymer in paper industry, is used to improve the barrier property of starch film. In this study, painting paper with exceptional barrier properties against organic solvents is successfully prepared for art creation purpose by coating a thin layer of environmentally friendly starch/PVA film on its surface. The coated paper can resist the penetration of the ink from marker pens. Furthermore, the solvent resistance and mechanical flexibility of freestanding starch/PVA hybrid film were investigated in detail. It found that the excellent barrier properties of the coated painting paper against solvents are due to the superior solvent resistance and mechanical flexibility of starch/PVA hybrid film. Therefore, the biodegradable and cost-effective strategy in this study provides a promising approach to enhance the barrier property of painting paper against solvents, which can find potential applications in painting field. [ABSTRACT FROM AUTHOR]

Cellulose nanofibril (CNF) papers have attracted great interests in recent years because of their attractive performance and the green resource of CNF. However, the thermomechanical properties of CNF papers are insufficient for some sophisticated applications that require higher mechanical properties or smart functionalities. In this paper, a dual bio-inspired strategy is reported to improve the thermal and mechanical properties, as well as the humidity-responsive behavior of CNF papers. CNF is first functionalized by mussel-inspired polydopamine, and then, composite CNF papers with nacre-like layered structure are fabricated by the incorporation of graphene oxide (GO). In addition, Fe3+ is introduced into the composite CNF papers to provide coordination cross-linking for each components. By such compositional and structural design, the composite papers demonstrate significantly enhanced mechanical properties as compared to original CNF paper. Meanwhile, the improved thermal stability and humidity-responsiveness are also demonstrated. This study is expected to provide alternative approach for high-performance and functional CNF materials. [ABSTRACT FROM AUTHOR]

Because of excellent insulation properties and thermal stability, meta-aramid paper can be commonly applied to a vast number of fields, like power systems. But poriferous and relatively lax structure of meta-aramid paper would limit its applications in high-voltage environment. This paper proposes a sandwich structure design to combine PDA@BNNS/PMIA film and meta-aramid paper with high breakdown strength. After coating with 6 wt% PDA@BNNS/PMIA solution, this kind of paper became more compact, so there were few pores in the paper and it further enhanced the mechanical and dielectric performances of specimens. The tensile strength in the cross direction increased from 31.3 to 40.5 MPa, and the performance in the machine direction was from 75.5 to 78.9 MPa. Furthermore, the breakdown strength of compound-coated paper achieved 55 kV/mm, which is much higher than meta-aramid paper. Additionally, compound-coated paper still remained outstanding thermal stability. Overall, our fabricated PDA@BNNS/PMIA compound-coated paper has excellent comprehensive properties, which provides a broad prospect for the applications in high-temperature and high-voltage transformers. [ABSTRACT FROM AUTHOR]

Melamine-impregnated paper is made by impregnating paper with melamine-formaldehyde resin and can be hot-pressed and laminated onto the surface of wood boards. If the paper has antibacterial activity, it can prevent the spread of indoor bacteria, but impregnated paper with a long-term antibacterial effect has not been proposed. Metal–organic frameworks (MOFs) have been studied as a reservoir of metal ions. In this study, a silver-metal organic framework (Ag-BTC) was synthesized by a green and scalable method at 60 °C (A-60) and at room temperature (A-25). The structure and thermal stability of the Ag-BTC were characterized. Compared with A-25, the structure and particle size distribution of A-60 were more regular and uniform. The thermal stability and the compatibility of Ag-BTC and MF resin were suitable for hot-pressing process. Ag-BTC in the cured impregnated paper exhibited the sustained-release performance of Ag+. The antibacterial ratio of decorated blockboards with 0.10 wt% A-25 to E. coli and S. aureus exceeded 99.99%, reaching Level I antibacterial grade. Compared with A-60-decorated blockboards, the better antibacterial activity of A-25-decorated blockboards was due to the release of more Ag+. This study provides new ideas for the design of antibacterial melamine-impregnated paper. [ABSTRACT FROM AUTHOR]

Electromagnetic interference (EMI) shielding materials with high performance and low density are urgently needed with the rapid development of electronic communications. In this work, tuning solid–air interface of graphene paper was carried out to enhance multiple reflections of incident electromagnetic waves for high-performance EMI shielding. The large amount solid–air interface (57.8 m2 g−1) endowed the porous graphene paper with a high EMI shielding effectiveness (SE) of 31.0 dB, 50% enhancement from its counterpart of solid graphene paper. This porous graphene paper also showed an ultralow density of 0.02 g cm−3, an 18.5-fold decrease from its counterpart of solid graphene paper. Moreover, the EMI SE of obtained graphene papers exhibited proportional relationship with their specific surface area, further confirming the vital role of solid–air interface in the enhancement of EMI shielding. This work quantitatively demonstrates the significance of solid–air interface area for enhancing the EMI shielding performance and proposes an efficient guideline for the design of high-performance and low-density EMI shielding materials. [ABSTRACT FROM AUTHOR]

Carbon fiber paper (CFP) has been widely investigated as a gas diffusion layer for high-performance fuel cells, while the paper formation, one of the most important properties of CFP, has been rarely reported before owing to the lack of accurate characterization methods. Herein, using a 2D laboratory sensor, a quantitative analysis was conducted to comprehensively analyze CFP formation, carbon fiber (CF) flocs and their influencing factors. Within the study scope of this paper, improved paper formation was always accompanied with a smaller floc area and a lower ratio of large-size flocs for CFP prepared with the same length of CF. CF was too long negatively affected paper formation, as the look-through index rose from 282 (2 mm CF) to 940 (8 mm CF). Either using polyethylene oxide as a disperser or reducing the CF concentration could reduce the look-through index of the CFP (2 mm CF) to below 200. The crowding factor of the CF suspension was suggested to be no more than 5. In addition, improvement in CFP formation led to higher tensile strength and lower air permeability in CFP. All these results are expected to prepare CFP with superior formation, thereby improving other properties of CFP. [ABSTRACT FROM AUTHOR]

The Journal of Materials Science awards the annual Robert W. Cahn Prize to recognize the best paper published in the journal each year. The winner of the 2023 Cahn Prize is a research paper titled "Molecular modelling of graphene nanoribbons on the effect of porosity and oxidation on the mechanical and thermal properties." The paper presents molecular simulation models of graphene nanoribbons and examines the impact of porosity and oxidation on their mechanical and thermal conductivity properties. The paper is well-written and provides valuable insights for researchers in this field. Two other papers were selected as runners-up for the prize. All the monthly finalists for the Cahn Prize can be downloaded for free on the journal's website. [Extracted from the article]

Fiber length and fiber-to-fiber bonding effects on tensile strength and fracture toughness of kraft paper have experimentally been investigated. Laboratory sheets were made from kraft pulp, each with a distinct set of fiber lengths. Additionally, the fiber-fiber bond strength was improved by carboxymethyl (CMC) grafting. The tensile strength and work of fracture toughness results were compared to predictions from a shear-lag model which considers the fiber-fiber bond shear strength, the fiber tensile strength and fiber pull-out work. The tensile strength and fracture work for papers with weak fiber-fiber bonds increased with fiber length consistent with the shear-lag model. CMC-treated fibers provided strong fiber-fiber bonds. Papers made from such fibers displayed high strength and work of fracture independent of fiber length which indicates that the failure process is governed by fiber failures rather than bond failures. The fracture toughness, expressed as the critical value of the J-integral, increased strongly with fiber length for both untreated and CMC-treated papers. The results show that long fibers and CMC addition are extremely beneficial for improving the fracture toughness. [ABSTRACT FROM AUTHOR]

The change of mechanical (folding endurance index, breaking stress, breaking length, breaking index, tear index ), optical (brightness), chemical (cold extract pH, alkali reserve) and physical (water absorbency by surface, smoothness) characteristics of 5 paper samples were measured during the accelerated aging at 105 ± 2°C, and the measured exponential dependencies were described and fitted by the formal first-order kinetics. The statistic parameters of such fitting calculations evidenced good agreement of the experimental and calculated data. The relative decrease of each paper property corresponding to 48 days of accelerated aging was evaluated in order to compare the durability of paper samples. The best aging resistance was obtained for paper MAESTRO® Classic (SCP Ružomberok, Slovak Republic) and this paper material may be recommended for archival applications. [ABSTRACT FROM AUTHOR]

It remains a challenge to prepare special engineering paper with excellent mechanical properties, high temperature resistance and chemical resistance. The emergence of high-performance fiber provides support for the technical progress of special engineering paper. Herein, a novel method to obtain a novel self-reinforced poly (ether ether ketone) (PEEK) composite paper (SR-DI-PEEK/paper) by vacuum filtration, impregnation and hot pressing. Specially, PEEK fibers were used as the skeleton fiber and a small amount of aramid pulp was added as the decanted fiber. By optimizing the process of SR-DI-PEEK/paper preparation, the best mechanical properties of SR-DI-PEEK/paper was presented. Compared with the composite paper prepared with Phenolic solution (PF-PEEK/paper) and Polyimide solution (PI-PEEK/paper), the mechanical properties of SR-DI-PEEK/paper was significantly improved. In particular, when the concentration of impregnation was 3 wt%, the tensile index of SR-DI-PEEK/paper reached 51.10 N m g−1 (tensile strength 47.16 kN m−1), which is 16.48 times than that of the un-impregnated PEEK/paper (2.86 kN m−1). SR-DI-PEEK/paper also exhibited excellent chemical resistance among acid, alkali, and polar solvents, while the tensile index maintained 96.3% after 40 wt% H2SO4 treatment. Besides, SR-DI-PEEK/paper showed superior thermal performance, while the temperatures corresponding to the weight loss of 5% were 574 °C. [ABSTRACT FROM AUTHOR]

The disappearance of bibliographic heritage is one of the biggest problems facing libraries. One of the most common methods used to restore paper, lining, is to apply a reinforcing layer to the document. This study focuses on lining papers with bacterial cellulose (BC) sheets from Gluconacetobacter sucrofermentans. For this purpose, several model papers have been selected. They have been characterized before and after the lining with this BC and a specific Japanese paper (JP) to compare both materials. Taking into account the differences between bacterial and vegetal cellulose is expected that the results may be similar to other BC and JP. The samples have been characterized before and after an aging process. There are no significant differences in some of the characteristics studied. Nevertheless, BC-lined papers present higher gloss values and b* coordinate. The wettability decreases with both BC and JP. However, in papers lined with BC, the wettability decreases more markedly and independently of the model paper used. This is related to the sealing of the surface structure by BC, which also leads to a reduction of air permeability. When the lined papers go through an aging process, there are no significant changes in any characteristic, except in b* and L* color coordinates. Additionally, the wettability rate decreases in all cases. This study indicates that papers lined with BC are stable over time. Finally, the use of BC as reinforcing material may offer advantages for specific conservation treatments, being more suitable for certain types of paper than JP. [ABSTRACT FROM AUTHOR]

Mechanical properties of fiber-based materials, such as paper, are governed by the heterogeneous microstructure induced by the formation process. For example, in paper materials during tensile tests, lower strains are observed in the flocs (fiber aggregates where the basis weight is larger than the average one) than in the antiflocs (complement of flocs). To explain such behavior, we investigated the mechanical and structural properties of both flocs and antiflocs. Using tensile tests on flocs and antiflocs, we measured their elastic modulus and found that the elastic modulus of flocs was larger than the antiflocs' one. To understand these differences, a multiscale structural analysis was conducted on 3D X-ray images of flocs and antiflocs at two different spatial resolutions. We found that the floc was thicker than the antifloc, whereas the microscale analysis showed the studied floc and antifloc exhibited the same bulk porosity. Then, it was concluded that the difference in elastic modulus between flocs and antiflocs is mainly due to their thickness difference. [ABSTRACT FROM AUTHOR]

Cellulose nanopaper consists of a dense fibrous self-binding network composed of cellulose nanofibres connected by physical entanglements, hydrogen bonding, etc. Compared with conventional printing paper, cellulose nanopaper has higher strength and modulus because of stronger fibres and inter-fibre bonding. The aim of this paper is to investigate the fracture properties of cellulose nanopaper using double edge notch tensile tests on samples with different notch lengths. It was found that strength is insensitive to notch length. A cohesive zone model was used to describe the fracture behaviour of notched cellulose nanopaper. Fracture energy was extracted from the cohesive zone model and divided into an energy component consumed by damage in the material and a component related to pull-out or bridging of nanofibres between crack surfaces which was not facilitated due to the limited fibre lengths for the case of nanopapers. For comparison, printing paper which has longer fibres than nanopaper was tested and modelled to demonstrate the importance of fibre length. Buckypaper, a fibrous network made of carbon nanotubes connected through van der Waals forces and physical entanglements, was also investigated to elaborate on the influence of inter-fibre connections. [ABSTRACT FROM AUTHOR]

The March 2024 issue of the Journal of Materials Science features a cover paper titled "Data-driven search for promising intercalating ions and layered materials for metal-ion batteries" by Shayani Parida and her colleagues at the University of Connecticut and EaglePicher. The paper, which falls under the "Computation & theory" Topical Collection, explores the use of density functional theory (DFT) calculations and machine-learning methods to identify alternative 2D materials and intercalating ions for high-power efficiency metal-ion batteries. The journal's Editor-in-Chief, Professor Jean-François Gohy, handled the paper, highlighting the journal's commitment to multidisciplinary research. The paper is freely accessible online, and additional details can be found in the Supplementary Information. [Extracted from the article]

The December 2023 cover paper of the Journal of Materials Science features a study by Xie and Luo from Chongqing Jiaotong University in China. The paper, included in the "Computation & Theory" Topical Collection, focuses on the use of carbon fiber-reinforced polymer (CFRP) for construction projects. The authors aim to provide insights into the transport behavior of liquids in epoxy-modified C–S–H pores in cement-based materials, combining MD simulations with experimental measurements. Xie is currently pursuing a master's degree in civil engineering, while Prof. Luo is an associate professor at Chongqing Jiaotong University and a researcher at Aarhus University in Denmark, with a focus on reducing the carbon and energy footprint of civil engineering materials and infrastructure. The paper is published open access and can be widely shared with readers using the provided link. [Extracted from the article]

In the engine of heavy trucks, the built-in fuel filter assumes the role of “lungs”. The core of the filter, namely the fuel filter paper, acts as a filter for small impurities and separates oil and water. In order to be able to separate minute impurities from the fuel, in this study, we prepared a novel fuel oil filter paper with high efficiency and high dust holding capacity based on wet-laid forming by laminating PBT/PP two-component melt-blown nonwoven material and cellulose nanocrystals (CNC)-doped cellulose wood fiber pulp with the fiber mesh combination forming technology. The effects of the CNC mixing ratio, surface density of melt-blown nonwoven material layer, surface density of cellulose wood pulp paper layer and calendaring pressure on the pore size and filtration performance of the composite samples were investigated, and the filtration efficiency of the composite samples on the tiny impurities in the fuel were also studied. The results showed that the novel composite fuel filter paper material prepared by the combined forming technology of fibrous web had high filtration efficiency and dust holding capacity, and the filtration efficiency of the composite samples could respectively reach 99.90% and 99.52% for particles larger than 14 μm and 4 μm in diameter in the fuel. At the same time, the dust holding capacity of the composite sample can reach up to 27.63 mgcm−2. [ABSTRACT FROM AUTHOR]

Preservation of documentary heritage is one of the biggest challenges facing paper conservators today. The singular properties of bacterial cellulose (BC) lead us to propose to reinforce paper with BC sheets. In the first part of this study, the reinforcing capability of BC was tested on model papers of well-known fiber composition. The aim of the present study was to verify the suitability of rebuilding degraded old papers with BC. The degraded papers were characterized before and after the reinforcement. In addition, lined samples were characterized before and after an aging process in order to study the stability in time. The same methodology was used with Japanese paper (JP), a material commonly used by paper conservators, in order to compare both materials as reinforcement. Mechanical properties of paper lined with BC are as good as those obtained with JP. Papers lined with BC have more marked modifications on their optical properties than those restored with JP. Nevertheless, letters in books lined with BC are more legible. Moreover, only the papers restored with BC show high changes in porosity. The aging process leads to a slight decrement in burst index. Changes on tear index and optical properties with the aging process depend on the paper to be restored. This study suggests that BC improves deteriorated paper quality, without altering the information contained therein, and that this improvement is maintained over time. Hence, BC is a promising alternative material for the restoration of paper. [ABSTRACT FROM AUTHOR]

We described a new concept, carbon paper-free membrane electrode assembly (MEA) fabricated from Nafion membrane and multi-walled carbon nanotubes-based electrocatalyst, in which platinum nanoparticles were deposited on carbon nanotubes after coating with pyridine-polybenzimidazole (PyPBI). Polymer-coated carbon nanotubes served as platinum nanoparticles support and current collector in carbon paper-free MEA. The fabricated carbon paper-free MEA was systematically studied by in situ cyclic voltammetry, SEM and fuel cell test. Pt utilization efficiency of carbon paper-free MEA improved with decreasing in Pt loading and reached 62% with 0.1 mg cm. Meanwhile, the mass power density reached 1.1 W mg, which was comparable to that of MEA with carbon paper. Fuel cell performance maintained 50% after 100000 startup-shutdown cycles, suggesting that carbon paper-free MEA was applicable in real fuel cell operation. To the best of our knowledge, this is the first study of carbon paper-free MEA in polymer electrolyte fuel cells. [ABSTRACT FROM AUTHOR]

The Journal of Materials Science has awarded the 2023 William Bonfield Prize for the best review paper to "Cement hydration mechanisms through time—a review" by Elisabeth John and Barbara Lothenbach. The review examines the work of Henri Louis Le Chatelier and William Michaëlis in the late nineteenth century and proposes pathways for future research in cement hydration mechanisms. The authors provide a comprehensive review with over 150 references, making it valuable for researchers in the field. The review was chosen by Professor Bonfield, who praised its analysis and contribution to the understanding of cement and concrete technology. Honorable mentions were also given to reviews on carbon dots, biopolymer-based treatments for cultural heritage materials, and superwetting membranes for oil/water separation. The William Bonfield Prize was created to honor Professor Bonfield's contributions to the Journal of Materials Science and materials research. [Extracted from the article]

We report on a corroborative study of the structural, morphological and electrical property alterations of free-standing graphene oxide (GO) papers subject to thermal reduction. Structural analysis performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Raman techniques prove that the onset of major structural changes, characterized by removal of oxygen functionalities, occur in the 200–300 °C temperature range. The results are corroborated with related morphological changes observed using Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) imaging. Elemental analysis shows the GO paper reduced at 600 °C to contain an 85 wt. % carbon content and a remnant oxygen level of 13.31 wt. %. At the highest reduction temperatures, we see evidence of vacancy-type defects impeding the overall effectiveness of the reduction process. Detailed electrical resistance measurements and current–voltage (I-V) profiling conducted using four-point probe method reveals a several orders of magnitude drop in the sample resistance once the reduction temperature exceeds 200 °C, in good agreement with the structural and morphological changes. The fundamental insights revealed through these studies will be important for future applications where the electrical and mechanical properties of free-standing GO and reduced graphene oxide (rGO) are exploited in practical devices. [ABSTRACT FROM AUTHOR]

Influence of the ion irradiation at elevated temperatures on the novel preceramic paper-derived SiCf/SiC laminated composites fabricated by spark plasma sintering was investigated. The composites were subjected to high-dose simultaneous irradiation of silicon (Si) ions at 400 °C. Irradiation induces amorphization of the damaged area up to 30 dpa, and then recrystallization of amorphous regions with increasing dose occur. No evidence of cavities was found in SiCf/SiC composites irradiated by silicon ions up to 100 dpa. The irradiated composites pre-injected with 5000 appm He displays low swelling (~ 0.3%). The irradiation with Si ions may suppress the cavity nucleation and they growth in SiC layers. [ABSTRACT FROM AUTHOR]

This study presents a comparison of the mechanical and barrier properties of papers coated with microfibrillated cellulose (MFC) by two different coating processes: (i) bar coating and (ii) size press. Due to the high water content of MFC, water-treated papers were taken as references to highlight the effects of MFC on the properties of papers. Structural, mechanical and barrier properties of the ensued materials were performed respectively with SEM, tensile and stiffness testers, and air and oxygen permeability equipments. The properties of the water-treated papers were considerably damaged compared to those of the base paper that underlined the negative impact of both coating processes on the papers structure. With MFC, the air barrier and the bending stiffness were considerably improved (+90 and +50 % respectively), especially when the bar coating was used, i.e. with 7 g m of MFC. Size press was indeed not able to considerably improve papers properties as the MFC coat weight barely reached 4 g m resulting from ten successive MFC layers. [ABSTRACT FROM AUTHOR]

Flexible graphene-based paper is promising for wide applications due to its outstanding electrical and thermal conductivities. Graphene flakes with large size are usually known as the key factor for improved paper performance. However, we find that a combination of flakes with large and small sizes is more favorable for both electrical and thermal conductivities than pure large flakes. In this work, flexible paper with enhanced electrical and thermal properties was fabricated by mixing graphene flakes with various size distributions. Large-size graphene (LSG) flakes play the role of a backbone structure, whereas small-size graphene (SSG) flakes fill the voids in the paper without disturbing the high orientation. The physical properties of the as-prepared graphene papers with contents of SSG varying from 0 to 100% have been investigated. It is found that the electrical and thermal conductivities of the paper with 25 wt% SSG are both around 140% higher than that of pure LSG paper. Our results indicate that the lightweight and flexible graphene-based paper has great potential for lateral heat dissipation applications requiring heat movement in a particular direction. [ABSTRACT FROM AUTHOR]

An analytical model is developed for the compression of coated substrates in a soft rolling nip formed between a hard roll and a soft covered roll. The coating layer, substrate, and soft cover are modeled as a stack of three layers that are compressed jointly while passing through the nip. Material models have been adopted separately for each of the three layers and were combined together according to the thickness of individual layers. In this study, the substrate is considered to be a viscoelastic–plastic material and is represented by a modified solid element while the coating layer is assumed to be elastic and the soft cover material is approximated by a standard Maxwell model. A strain function is derived for the compression of substrate in the nip that appears to be a parabolic function of time. Substrate compression in the nip and its subsequent relaxation are calculated by solving a set of differential equations that describe the coating, substrate, and soft cover deformations. This model is used to study the soft-nip calendering of coated papers. Examples of numerical modeling that demonstrate the paper deformation and stress profiles in the nip are presented. In addition, the effects of paper and cover properties as well as calendering parameters on the dynamics of paper compression are discussed. Finally, a comparison of the modeling results is made with the experimental data. [ABSTRACT FROM AUTHOR]

Herein, an eco-friendly and straightforward method was provided for the fabrication of superhydrophobic paper from native wood cellulose fibers via in situ hydrolysis of tetraethyl titanate(IV) without any chemical pretreatment. By simply adjusting the amount of acetic acid (HAc), the surface micro/nanomorphology could be well controlled. After papermaking and hexadecyltrimethoxysilane modification, superhydrophobic paper can be easily achieved with static water contact angle of 152.3° (± 1.3°). The paper also possessed good self-cleaning property against contamination and durability toward mechanical damages of finger wiping over 50 cycles as well as excellent oil/water separation, which expands its utility in various paper-based technologies. The whole procedure possesses the advantages of friendly raw material, mild reaction conditions and with no toxic modifier, which hold potential application in cellulose-based superhydrophobic material in large scale. [ABSTRACT FROM AUTHOR]

Biogas-powered fuel cells that use low-quality biogas produced from organic waste hold a great promise for providing ultra-clean electric energy with on-site power generators. However, natural biogas contains a small amount of HS, which causes a rapid deactivation of steam-reforming metal catalysts, such as Ni. In this work, we successfully prepared two types of paper-structured catalyst, separately containing manganese oxides (MnO) and nickel/magnesium oxides (Ni/MgO), for desulfurization and methane-steam reforming, respectively. In the sequential desulfurization and methane-steam reforming, paper catalyst assembly, designed by stacking MnO papers upstream and Ni/MgO papers downstream in a dual-layered form, enabled continuous hydrogen production from simulated biogas containing ca. 2000 ppm HS impurities, whereas single-layered Ni/MgO papers immediately lost their catalytic activity due to the HS poisoning. This combination of flexible, stackable, and easy-to-handle paper-structured catalysts has the potential to improve the energy efficiency and to process economics of providing hydrogen to biogas-powered fuel-cell systems. [ABSTRACT FROM AUTHOR]

As one of the most promising energy-storage devices, supercapacitors have drawn great research interests because of their outstanding electrochemical behavior. Carbon paper holds great prospect as an electrode material for supercapacitors since it is inexpensive and highly conductive. In this paper, the modified Hummer's method is employed as an effective strategy to produce activated carbon paper with rougher surfaces and increased specific surface areas. It is further observed that hydrophilic groups such as hydroxyl (-OH), carbonyl (>C=O), and carboxyl (-COOH) have been introduced into the surface of carbon paper over treatment and they serve as strong polar sites to absorb water molecules, leading to improved hydrophilicity. Thus, the as-treated carbon papers with both increased specific surface areas and improved surface hydrophilicity exhibited excellent capacitive characteristics. Moreover, the charge/discharge test over 2000 cycles shows their excellent long-term capacitive retention. [ABSTRACT FROM AUTHOR]

Smoothness is an important factor in consumer perception of tissue quality, with physical modification and chemical additions to the paper able to enhance tissue handle. Therefore objective measurement of the papers mechanical properties in developing new products and maintaining existing quality is vital. In this study the surface chemical composition of the softener treated paper is investigated using ToF-SIMS, and related to the surface frictional properties of the paper. [ABSTRACT FROM AUTHOR]

Graphical abstract: [ABSTRACT FROM AUTHOR]

Excellent mechanical and electrical properties of graphene-based paper-like materials are essential for applications in flexible conductors, energy-storage devices, etc. The graphene oxide (GO) supernatant separated by centrifugation and ultrasonication has been used to prepare graphene oxide paper and reduced graphene oxide paper (rGOP) with high strength and conductivity. However, this method has cumbersome steps and low supernatant concentration, which greatly increases time and energy consumption, and is not suitable for rapid batch preparation of high-strength and high-thickness rGOP. Herein, a high-speed mechanical shearing method has been used to efficiently exfoliate graphite oxide suspension into high-concentration GO slurry with large lateral size, and rGOP has been further prepared by blade coating and HI acid chemical reduction. Compared with the product prepared by ultrasonic exfoliation method, the average area of GO sheets obtained via the mechanical shear exfoliation method can reach around 16.31 μm2. As a result, the mechanical properties and conductivity of the prepared rGOP have been increased by 30% and 23.5%, respectively, with the tensile strength and electrical conductivity of 478.2 MPa and 208.4 S/cm being obtained. The developed method is of great significance for the large-scale production and emerging applications of lightweight and high-performance rGOP. [ABSTRACT FROM AUTHOR]

In this study, nylon microcapsules were prepared on a paper surface using an interfacial polymerization technique for the preparation of smart paper. Filter paper impregnated with ethylenediamine solution and NaOH solution was left in a beaker containing cyclohexane or chloroform. Subsequently, the organic solvent terephthaloyl chloride was added to the beaker and interfacial polymerization occurred on the paper surface. When cyclohexane was used as the organic solvent, formation of nylon microcapsules on the paper surface was confirmed. Fixation of nylon microcapsules on the paper surface was successfully performed using interfacial polymerization. On the other hand, it was not possible to form nylon microcapsules on the paper surface when interfacial polymerization with chloroform was carried out. These results are due to differences in the spreading coefficient of the organic solvent on the ethylenediamine solution adsorbed on the paper surface. [ABSTRACT FROM AUTHOR]

Cellulose insulation paper as a part of oil-paper insulation systems plays an important role in the reliability of converter transformers. The reliability of converter transformers equipped with traditional cellulose paper is adversely affected by space charge under DC voltage. The addition of nanoparticles into other dielectrics has been demonstrated to improve electrical performance. However, studies on the space charge behavior of cellulose paper reinforced with nanoparticles are rarely reported. This paper presents the results of a study aimed at elucidating the effect of nano-aluminum nitride (AlN) concentration on the space charge behavior of cellulose paper. Samples with various nano-AlN concentrations were fabricated and pretreated first. The micro-morphologies of prepared cellulose papers were observed using a field-emission scanning electron microscope. The space charge distribution was measured using a pulsed electroacoustic instrument. The results show the dependence of the charge injection as well as charge dissipation on the concentration of nano-AlN. The isothermal decay current method is used to obtain trap information. Based on the density and distribution of traps, the underlying mechanism of the effect of various concentrations on the space charge behavior is theoretically explained. [ABSTRACT FROM AUTHOR]

Professor Grimes summarizes the winning paper and the two runners-up:"Machine learning is certainly of great current interest to address the multivariable materials design challenge. 10.1007/s10853-022-07499-9 5 Wang Z, Lai A, Schuh CA, Radovitzky R. Phase transformation and incompatibility at grain boundaries in zirconia-based shape memory ceramics: a micromechanics-based simulation study. The winner of the 2022 Robert W. Cahn Best Paper award is "Machine learning guided alloy design of high-temperature NiTiHf shape memory alloys" by Udesh M.H.U. Kankanamge, Johannes Reiner, Xingjun Ma, Santiago Corujeira Gallo, and Wei Xu. [Extracted from the article]

The use of cyclopropenone derivatives as latent photo-released strained cyclic alkynes is reported for the covalent printing of complex patterns on cellulose paper. Two different approaches using either a UV LED or a laser as light irradiation source are discussed. While the high intensity of the laser damages the grafted molecular layer, the use of a simple UV LED allows the printing in only 8 min at room temperature with a good resolution at the micrometer scale with negligible diffusion. The validity of this strategy is demonstrated through the sequential printing of a QR code and a logo on the same paper sheet. [ABSTRACT FROM AUTHOR]

Highly flexible electromagnetic interference (EMI) shielding material with excellent shielding performance is of great significance to practical applications in next-generation flexible devices. However, most EMI materials suffer from insufficient flexibility and complicated preparation methods. In this study, we propose a new scheme to fabricate a magnetic Ni particle/Ag matrix composite ultrathin film on a paper surface. For a ~ 2-µm-thick film on paper, the EMI shielding effectiveness (SE) was found to be 46.2 dB at 8.1 GHz after bending 200,000 times over a radius of ~ 2 mm. The sheet resistance (R□) remained lower than 2.30 Ω after bending 200,000 times. Contrary to the change in R□, the EMI SE of the film generally increased as the weight ratio of Ag–Ni increased, in accordance with the principle that EMI SE is positively related to an increase in electrical conductivity. Desirable EMI shielding ability, ultrahigh flexibility, and simple processing provide this material with excellent application prospects. [ABSTRACT FROM AUTHOR]

We demonstrate in this paper that commercially available printing paper can reach very high fracture toughness, comparable to that of steel, simply due to a special arrangement of the paper sheets with respect to the crack. Fracture mechanics experiments are conducted on single sheets of paper as well as on multilayer specimens in crack divider and crack arrester configuration. It is demonstrated that an arrangement in crack arrester configuration leads to an increase of the fracture toughness by a factor ten. An explanation of the effect is given and the transferability to other materials is discussed. [ABSTRACT FROM AUTHOR]

Multiwalled carbon nanotubes (MWNT) were deposited via dropcasting and dried using vacuum filtration. Because of the slightly larger pore size (5–10 µm) of the paper substrate used as compared to the length of the nanotubes (0.5–2 µm), a variety of MWNT networks were formed both on the surface and through the thickness of the paper. Using a combination of impedance spectroscopy, equivalent circuit modeling, and microscopy techniques, it was possible to describe in detail how the electrical properties change as a function of how the MWNTs are distributed on the porous substrate by varying the number of deposited layers (1–20) as well as the dispersion concentration (0.1–5 mg/mL). In the in-plane, four different electrical responses were observed and modeled: (1) a substrate dominated spectrum representing unconnected MWNTs, (2) one that included bundle and junction responses as well as some inductances representing sparsely distributed MWNT networks, (3) followed by a parallel RL circuit for partially connected MWNT networks, and (4) finally a series RL circuit for fully connected MWNT networks. In the thru-plane, only two different electrical responses were observed and modeled. The results for the in-plane and thru-plane properties were used to generate percolation curves that show that electrical conductivity can change as much as 10 orders of magnitude for the same exact MWNTs. These results indicate that not only do the characteristics of the nanotubes themselves play a role but also the structure of the underlying substrate and the details of how the films are deposited. [ABSTRACT FROM AUTHOR]

The ability of the bacteria Gluconacetobacter sucrofermentans to produce high-quality cellulose is well known. This bacterial cellulose has unique properties, as the result of an ultrathin crosslinked structure. It is almost chemically pure (until 98% cellulose), has a high crystallinity, mechanical strength, elasticity and durability. It is compatible with plant cellulose and could be grown on a vegetal fibrous network what makes bacterial cellulose an excellent candidate to reinforce damaged papers. The objective of this work is to promote the production of bacterial cellulose on the surface of a variety of papers by the direct application of a culture of G. sucrofermentans and to test if this procedure could be an economic and feasible possibility in reinforcing papers or cellulosic surfaces. After 7 days of cultivation, G. sucrofermentans deposits a thin layer (ca. 10 µm) of bacterial cellulose on the papers surfaces. Microscopic observations have shown a heterogeneous covering of the surfaces, while the modified papers maintain their thickness and their basic weight. The treatment has not increased the papers mechanical properties, but maintains them after artificial aging. The changes in optical properties of the reinforced papers, such as opacity and colorimetric coordinates, are minor even after further aging. Air permeance is the paper characteristic that experiences more variations because the layers of bacterial cellulose inhibit the airflow through the papers. The changes in the static and dynamic contact angles suggest that the bacterial cellulose structure is more compact and make the surface more hydrophobic than the original paper surface. [ABSTRACT FROM AUTHOR]

Sulfur quantum dots are promising alternatives for traditional heavy metal-containing quantum dots due to their benign chemical properties and low cytotoxicity. Herein, cysteine-decorated sulfur dots were prepared from facile modification of pristine sulfur dots and can be acted as a chemosensor for the fluorometric and colorimetric dual-channel detection of cobalt (Co2+) with high sensitivity and selectivity. Visual colors of the as-prepared chemosensor in the presence of Co2+ changed from blue to colorless under UV light and also can transform from colorless to yellow under sunlight based on the photoinduced electron transfer effect. The detection limit of cysteine-decorated sulfur dots toward Co2+ was determined as low as 0.16 μM with a wide detection range, which is lower than the permitted guideline level by Department of Environmental Protection for drinking water (1.7 μM). Furthermore, portable paper sensor-based cysteine-decorated sulfur dots were fabricated for Co2+ detection and showed superior detection ability. Aided by a common smartphone as detector, the rapid, on-site and accurate quantification of Co2+ in real water samples can be accomplished. Our research has provided a novel chemosensor based on sulfur dots for dual-channel detection of Co2+, which would expand applications of sulfur dots in environmental monitoring, diseases diagnosis, cell imaging, light-emitting diodes, etc. Cysteine-decorated sulfur dots were acted as a chemosensor for fluorometric and colorimetric dual channel detection of Co2+ based on the photoinduced electron transfer effect. [ABSTRACT FROM AUTHOR]