Papermaking Technique Research Articles

Flexible and Free-Standing Metal-Organic Framework Nanowire Paper.

Beyond traditional paper, multifunctional nanopaper has received much attention in recent years. Currently, many nanomaterials have been successfully used as building units of nanopaper. However, it remains a great challenge to prepare flexible and freestanding metal-organic framework (MOF) nanopaper owing to the low aspect ratio and brittleness of MOF nanocrystals. Herein, this work develops a flexible and free-standing MOF nanopaper with MOF nanowires as building units. The manganese-based MOF (Mn-MOF) nanowires with lengths up to 100 μm are synthesized by a facile solvothermal method. Through a paper-making technique, the Mn-MOF nanowires interweave with each other to form a three-dimensional architecture, thus creating a flexible and free-standing Mn-MOF nanowire paper. Furthermore, the surface properties can be engineered to obtain high hydrophobicity by modifying polydimethylsiloxane (PDMS) on the surfaces of the Mn-MOF nanowire paper. The water contact angle reaches 130°. As a proof of concept, this work presents two potential applications of the Mn-MOF/PDMS nanowire paper: (i) The as-prepared Mn-MOF/PDMS nanowire paper is compatible with a commercial printer. The as-printed colorful patterns are of high quality, and (ii) benefiting from the highly hydrophobic surfaces, the Mn-MOF/PDMS nanowire paper is able to efficiently separate oil from water.

木材パルプ／バイオプラスチック積層複合材料の表面処理による力学特性の改善

In this study, wood-pulp／bio-based poly (butylene succinate) (Bio-PBS) laminated composites were made by using papermaking techniques. Wood-pulp fibers were treated with 3-aminopropyltrimethoxysilane (APTMS) and poly (vinyl alcohol) (PVA) to improve the interfacial adhesion between the wood-pulp fibers and Bio-PBS. Wood-pulp fibers without being processed (PF), wood-pulp fibers treated by APTMS (PF-Si), and wood-pulp fibers treated by both APTMS and PVA (PF-Si/PVA) were converted to sheets by the papermaking technique. Those sheets and Bio-PBS films were used to make wood-pulp/Bio-PBS laminated composites by hotpressing and cut into test pieces. Tensile testing and the heat distortion temperature measurements were conducted with those samples. As a result, the tensile strength of composites was close in value to that expected by the Reuss model when the volume fraction of wood-pulp was 12％ and 24％. Furthermore, the tensile strength of composites containing PF-Si/PVA was higher than that of composites containing PF and PF-Si. The heat distortion temperature of the composites was higher than that of Bio-PBS, although the effects of surface treatment on the heat distortion temperature were not confirmed. Microscopy observations of composite fractures indicated that the surface treatment of wood-pulp fibers enhanced interfacial adhesion between the woodpulp fibers and Bio-PBS.

Effect of papermaking technique parameters on air permeability and sound insulation of glass fiber felt

Glass fiber felt (GFF) as a fibrous and porous material has caught much attention because its light mass, low cost and excellent acoustic properties. In this paper, GFF was prepared via the papermaking technique to explore the correlation between glass fiber suspension characteristics and physical properties (uniformity, air permeability and sound insulation) of GFF. The consequence presented that increasing the dispersing times and speeds could decrease aspect ratio and flocculation of fibers, which was useful to improve viscosity and fiber hanging property of glass fiber suspension, and uniformity of GFF. However, there was no visible impact on the air permeability of GFF. The results also indicated that increasing the dispersing times could decrease sound transmission loss (STL), however which could be enhanced by changing the dispersing speeds. The optimal dispersing speed was 3000 r/min and STL could be reached 15.78 dB at 6300 Hz. Generally, GFF could be used as acoustic material for building and transportation.

Examination of Weight Fluctuation Factors of Handmade Japanese Paper

Papermaking technique is implicit knowledge based on many years of experience of craftsmen. In this study, we investigate the factors that cause the weight of Japanese paper to vary depending on the papermaking conditions. The subjects of the survey are the measurement of the movement of the "suketa". The movement of the "suketa" is measured using a motion sensor. The measurement results suggest that the craftmen adjust the choushimizu time.

Ceramic Papers as Structured Catalysts: Preparation and Application for Particulate Removal

Fibers represent a type of structure of great interest in catalysis since they combine high area to volume ratio and can be fabricated from many types of materials, such as ceramic oxides, polymers, and alloys. They can be used in isolated form or structured, as in the case of the ceramic papers synthesized in this work, following a modified papermaking technique. The addition of cationic and anionic polyelectrolytes improved the retention of ceramic fibers during the ceramic paper formation stage by adsorption processes, through the formation of floccules. In the complex aqueous system containing charged macromolecules, the amounts of polyelectrolytes to be added were determined by titrations. To enhance mechanical properties of ceramic papers, different classes of nanoparticle suspensions can be used as binders. As a novel alternative, we have used different borate-type compounds. Among them, we selected natural ulexite, which was purified and used as a binder of ceramic fibers. In order to improve mechanical resistance and flexibility, measured from tensile indexes and elastic module, the amounts of NaCaB5O6(OH)6.5H2O and the calcination temperature were varied. In this contribution, to take advantage of the unique characteristics of the ulexite-containing ceramic papers, they were impregnated with Co,Ce and Co,Ba,K and tested for diesel soot combustion.

Paraffin particle dispersion costabilized by W-doped VO2 nanoparticles and chitosan for the fabrication of functional nanocellulose film

The development of functional window films for energy savings and privacy protection has attracted considerable attention. Herein, a functional nanocellulose film was fabricated via a papermaking technique by using the naturally formed network structure of nanocellulose film to obtain privacy protection and to encapsulate paraffin particles stabilized by W-doped VO2 nanoparticles and chitosan. The paraffin particles stabilized by W-doped VO2 nanoparticles and chitosan were prepared via an emulsion approach without using surfactant. The incorporation of paraffin into the nanocellulose film not only enhances the latent heat and lowers the forward transmittance of the nanocellulose film but also improves its hydrophobicity. The presence of a small amount of W-doped VO2 nanoparticles in the paraffin particle dispersion further increases the forward transmittance and latent heat of the nanocellulose film, especially at elevated temperatures. Meanwhile, the introduction of chitosan in the paraffin particle dispersion significantly improves the toughness of the nanocellulose film. Consequently, the incorporation of paraffin particles endows the nanocellulose film with hydrophobicity and toughness as well as good privacy protection and thermal insulation for energy savings at both room and elevated temperatures, making the as-prepared nanocellulose film a promising functional window film.

Polyphenylene sulfide scaffold based flexible supercapacitor electrode with competitive areal capacitance and flame-retardant behavior

Flexible supercapacitor electrode has been strongly developed as next-generation wearable energy storage electronics in the last decades. The state-of-the-art performance always requires the implantation of compelling energy-storage stuff and flexible scaffolds. However, the inflammable nature of such supercapacitors gives rise to safety issues, and it is a challenge to maintain high energy storage capability and flame-retardant behavior synergistically. Herein, we use a paper-making technique to engineer polyphenylene sulfide (PPS) ultrafine fibers and multi-walled carbon nanotubes (MWCNT), followed by the deposition of in-situ polymerization polypyrrole (PPy). This highly porous electrode exhibits a high areal capacitance of ~1650 mF cm−2 at a current density of 1 mA cm−2, and > 93% of capacitance retention after 5000 charging-discharging cycles at a current density of 20 mA cm−2. Notably, PPS/MWCNT/PPy electrode features noninflammability and zero generation of dense fume in the open flame. Also, the areal capacitance of the electrode remains more than 50% after 0.5 h annealing at 200 °C. This work delivers a new PPS scaffold-based supercapacitor electrode-manufacturing system directing at high energy-storage capability and harsh-environment adaptability.

Flexural and shear strength properties of unidirectional carbon fiber reinforced polymer composite interleaved with recycled carbon fiber and short virgin aramid fiber non-woven mats

Carbon fiber reinforced polymer composites (CFRPs) are one of the most widely used composite types and wastes associated with them (CFRPs) get generated through either their manufacturing or end-of-service-life. Predominately due to environmental concerns and governmental regulations, recycling these CFRPs is needed and to make use of the recycled carbon fibers (rCFs), a wet paper-making technique was used to convert the rCFs into a 60 g/m2non-woven mat. For comparison purposes, the same technique was used to convert short virgin aramid fibers (vAFs) into a 60 g/m 2 non-woven mat. Each mat was sandwiched with two resin films and then interleaved with 12-ply unidirectional (UD) prepreg tapes (carbon/epoxy). The assemblage was molded into composite laminates using a vacuum bagging assisted compression molding technique, and the samples for the tests were cut using a waterjet machine accordingly. Compared with the control, the results indicate an increment in the flexural modulus, and the specific flexural modulus for the CFRPs with non-woven mats: the flexural modulus increased by approximately 8.2% and 12.0% for the CFRP with rCF and vAF mats, respectively; the specific flexural modulus increased around 9.5% and 13.3%, respectively for the CFRP with rCF and vAF mats. On the other hand, the shear strength approximately decreased by 6.4% and 6.0% for the CFRP with rCF and vAF mats, respectively. The negative shear strength performances of the composite laminates with non-woven mats reflected on their flexural strength performances: the flexural strength increased about 1.1% and decreased by approximately 7.9% for the CFRP with vAF and rCF mats, respectively. To resolve the negative shear strength performances, it is recommended that the surfaces of the mats be treated with a coupling agent to improve their interfacial adhesions.

Preparation of high-performance flexible microsupercapacitors based on papermaking and laser-induced graphene techniques

We report a new method to prepare high-performance flexible microsupercapacitors (MSCs) via the combination of papermaking technique and laser-induced graphene (LIG) technique. The papermaking technique allows the massive production of poly(p-phenylene benzobisoxazole) (PBO) paper, and the LIG process can directly convert the PBO paper into graphitized material. The resulting material exhibits excellent capability as electrode materials for MSCs thanks to the highly graphitized degree of PBO paper to improve the conductivity of the electrode and the formation of excessive nano-sized bumps to increase the surface area, which are two crucial factors for good MSCs. The largest areal specific capacitance can reach as high as 46.3 mF cm−2 and is 12 times higher compared to that of MSCs prepared with the polyimide (PI) as a LIG substrate. The MSCs prepared from different PBO papers demonstrate high reproducibility, and the maintenance of 85% specific capacitance after 3000 cycles bending tests reveals their excellent flexibility. Owing to the high-performance capacitance, easy preparation, and massive production of MSCs, we envision that this technique can be widely applied for the preparation of energy storage devices.

Kemal Beydilli, Two İbrahims: Müteferrika and His Successor – Off The Founders of The Ottoman Printing Press

The Ottoman Turks started using the printing press technology for the first time in 1727, thanks to the efforts of İbrahim Müteferrika, a Hungarian convert to Islam. If the history of printing is examined, readers can observe that the wood- block printing in China’s Tang Dynasty had been prevalent as early as the 8th cen- tury. Over all, Muslims had good relations with Chinese during the Tang Dynasty as they borrowed papermaking technique from them but not the printing tool. Later on, the Ottomans also were not interested in it although they had contacts with China since their early days. In Germany, around 1440, goldsmith Johannes Gutenberg invented the printing press, and there were several points of interac- tions between Europe and the Ottoman Empire. However, the Ottoman Muslims were not interested in this new innovation for a long time, although non-Muslim subjects of their Empire had shown interest early on. As well-known, Gutenberg’s important innovation was the development of hand-molded metal printing mat- rices, thus producing a movable type–based printing system which enabled large number of books, pamphlets and other materials to be printed.

Highly Conducting Nanographite-Filled Paper Fabricated via Standard Papermaking Techniques.

Eco-friendly and cost-effective materials and processes to manufacture functional substrates are crucial to further advance the area of printed electronics. One potential key component in the printed electronics platform is an electrically functionalized paper, produced by simply mixing common cellulosic pulp fibers with high-performance electroactive materials. Herein, an electronic paper including nanographite has been prepared using a standardized and scalable papermaking technique. No retention aid was needed to achieve a conducting nanographite loading as high as 50 wt %. The spontaneous retention that provides the integrity and stability of the nanographite paper, likely originates partially from an observed water-stable adhesion of nanographite flakes onto the fiber surfaces. The resulting paper exhibits excellent electrical characteristics, such as an in-plane conductivity of 107 S/cm and an areal capacitance of 9.2 mF/cm2, and was explored as the back-electrode in printed electrochromic displays.

Research on the application of VR technology in the digital inheritance of ancient papermaking technology

The traditional papermaking technique of ancient method is confronted with the problem of difficult inheritance. In order to enable the public to experience or learn the ancient papermaking technology with the help of virtual platform and make the ancient papermaking technology have more possibilities for future development, the VR experience project of ancient papermaking technology is designed and planned through data collection, virtual scene production, digital interactive design and other steps by means of integrating disciplines. It can retain the integrity of the information of ancient papermaking technology to the greatest extent, provide a safe, efficient and green simulation learning platform, rapidly promote the traditional ancient papermaking culture in a large range, enrich the presentation of ancient papermaking materials and predict the future development direction.

“Paper Dye-Sensitized Solar Cell” Based on Carbon-Nanotube-Composite Papers

We propose a paper solar cell based on carbon nanotube (CNT)-composite papers. To fabricate this cell, we use dye-sensitized solar cells (DSCs) for generating power through the redox reaction of dyes in conjunction with CNT-composite papers, which are composite materials containing CNTs and pulp (raw paper material) that can be fabricated easily by using a method based on the Japanese washi papermaking technique. The demand for CNT applications is expected to increase due to their high conductivity and metallic or semiconducting characteristics. This CNT-composite paper can also have metallic or semiconducting characteristics based on the contained CNTs in the composite paper. We previously fabricated a DSC that generates electricity by using CNT-composite papers stacked in a typical DSC structure. However, the conversion efficiency of this DSC was just 0.188%, which is not practical. To overcome this low power generation issue, we tried improving the DSC structure by applying electrodes to the CNT-composite papers in grid patterns for efficient current collection and applying an optimally mixed dye for efficient electron excitation. Results showed that the conversion efficiency improved to 0.58%. Moreover, we demonstrated that using a mixed dye can improve the conversion efficiency of the paper DSC. We expect these types of CNT-composite papers to be used as material for new DSCs.

Cellulose fibre- perlite depth filters with cellulose nanofibre top coating for improved filtration performance

Depth type composite filters are used to remove contaminants from liquids by combining mechanical entrapment and adsorption. Commonly, depth filters can adsorb either anionic or cationic charged contaminants, but not both, as well as filter micron-sized particles. Therefore, there is still a need to improve the existing depth filter performance. In this study, we developed a two-layer filters with enhanced functionality by spray coating an anionically charged cellulose nanofibre (CNF) layer onto a cationically charged depth filter layer. The depth filter layer was prepared via papermaking technique of vacuum filtration from wood pulp fibres, perlite adsorbent and cationic polyamide-amine epichlorohydrin (PAE) wet strength resin. The CNF coat weight ranged from 4 to 30 g per square metre (gsm). The two layer filters were proven to have triple functionality, capable of adsorbing anionic molecules in the cationic depth filter layer, while the anionic CNF layer could adsorb cationic molecules and was also a microfiltration membrane. A gradual increase in CNF coat weight improved filtration performance but decreased the filter flux. The optimum performance was found at an 8 gsm CNF coat weight, where the membrane layer rejected 80% of 5000 kDa molecular weight polyethylene glycol, at a flux of 133 Litres per square meter per hour (LMH) under 1.5 bar pressure, while still achieving a good breakthrough curve when absorbing cationic methylene blue dye.

In Situ Green Synthesis and Functionalization of Reduced Graphene Oxide on Cellulose Fibers by Cannabis sativa L. Extract

Abstract The last decade has seen an enormous rise in the use of green reducing agents, such as plant extracts, for the chemical synthesis of several materials in view of the limitations of conventional reducing agents, such as their toxicity and instability. This study reports the green reduction and simultaneous functionalization of graphene oxide on cellulose fibers using the aqueous extract from the inflorescences of Cannabis sativa L. The graphene oxide, synthesized using the modified Hummer’s method, was reduced in situ on the cellulose matrix in the presence of the extract at elevated temperatures without external stabilizers in order to functionalize the fibers with reduced graphene oxide (RGO). The cellulose fibers not only acted as a flexible, biodegradable, and cost-effective matrix for the anchorage of RGO but also supported in situ reduction on the fiber surface. Different weight fractions of RGO, from 0.1 to 10 wt %, were used to fabricate RGO/cellulose composites by paper-making technique, which were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy techniques. The RGO sheets uniformly covered the surface of the cellulose fibers and dispersed well within the fiber matrix. The surface resistivity at 40 V decreased with increasing RGO content from 1.81 × 1011 Ω for 0.1 wt % RGO to 0.15 × 1011 Ω for 10 wt % RGO loading. The presence of air voids between the fibers hindered the physical contact between the RGO layers, thereby preventing the formation of an effective conductive network and significantly affecting the performance of the composites. Likewise, the surface charging capacity of the composites at 40 V dropped from 1.21 × 10−3 ΔmAh for 0.1 wt % RGO to 0.05 × 10−3 ΔmAh for 10 wt % RGO content, indicating a rise in conductivity with RGO loading. These composites show immense potential as sustainable materials for portable energy storage devices, such as capacitors.

The use of cellulose nanofibres to reduce the wet strength polymer quantity for development of cleaner filters

Polyamideamine-epichlorohydrin resin (PAE) is one of the most commonly used wet strength agents in the papermaking industry. However, adsorbable organic halogens (AOX) are known to be a toxic side product of the PAE manufacturing process; therefore, the use of PAE is restricted by regulation for food and medical applications. In this study, we investigated partially replacing the indirect food additive, PAE, with a renewable, biodegradable material, cellulose nanofibres (CNF), in order to drastically reduce the amount of PAE used while maintaining the same wet tensile strength. The concept is to replace covalent bonds by hydrogen bonds and to drastically increase bonding area. Depth-type filters were prepared with cellulose (30%), perlite (70%) and lesser amounts of PAE via papermaking technique. A small fraction of cellulose fibre composition was substituted with CNF while the PAE amount was gradually decreased. The substitution of positively charged PAE for negatively charged cellulose nanofibres switched the overall charge of the system from cationic to anionic. Therefore, two cationic polyelectrolytes, CPAM or PEI, were investigated to control the overall charge and adsorption performance of the filter system.The substitution of CNF enabled PAE dosage to be reduced by over 95% while retaining the wet strength properties of the filters. The wet strength obtained from the small quantity of wet strength polymer could be further improved by increasing the curing temperature to 150 °C with a much shorter curing period. The filters with reduced PAE dosage have also improved adsorption of positively charged contaminants. However, for negatively charged contaminants a very minor amount (around 20 mg/g) of cationic polymer addition would be required to maintain the performance. Our study shows that partial replacement of conventional papermaking fibres with cellulose nanofibres allows us to reduce the quantity of wet strength polymer remarkably and achieve a sustainable and environmentally-friendly concept for filter manufacturing or for any paper product requiring wet strength.

Ultrasound-Assisted Deposition of Co-CeO2 onto Ceramic Microfibers to Conform Catalytic Papers: Their Application in Engine Exhaust Treatment.

The combination of the selective catalytic reduction technology with catalytic filters constitutes one of the most efficient ways for diesel engine exhaust treatment. In this paper, the development of catalytic ceramic papers as structured systems for the abatement of diesel soot particles is addressed. Ceramic papers were prepared by the dual-polyelectrolyte papermaking method, which is based on the conventional papermaking technique used for cellulosic papers, in which a portion of cellulosic fibers is replaced by ceramic ones. The deposition of Co and Ce as catalytic materials by the wet spray method on ceramic papers was studied for the development of structured catalysts using an ultrasonic nebulizer and different solvents. The use of alcohol–water solutions for the impregnation of cobalt generated smaller particles and a high dispersion of them on the ceramic fibers, greater than that obtained when pure water was employed. Temperature programmed oxidation (TPO) assays showed that the best catalytic performance was acquired with the catalysts generated with alcohol solvents, showing a maximum rate for soot combustion at a temperature close to 400 °C. The adequate soot combustion performance and the high thermal and catalytic stability make catalytic ceramic papers impregnated by the wet spray method, promising systems for their application as diesel particulate filters.

Continuous removal of Cr(VI) and Orange II over a novel Fe0-NaA zeolite membrane catalyst

A novel Fe0-NaA zeolite membrane catalyst was prepared for continuous removal of Cr(VI) and Orange II (OII) in a fixed bed reactor. Firstly, the NaA zeolite membrane on the paper-like sintered stainless steel fibers support was prepared by wet lay-up papermaking technique and secondary growth method. Then, Fe0-NaA zeolite membrane catalyst was synthesized by traditional liquid-phase technique and characterized by using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Finally, catalytic activity of Fe0-NaA zeolite membrane catalysts was studied by investigating the breakthrough time of Cr(VI) and conversion of OII as well as the iron leaching concentration in the effluent based on the reduction reaction and catalytic wet peroxide oxidation (CWPO) processes in a fixed bed reactor. The results showed that nanoscale Fe0 particles were uniformly loaded on the surface of the NaA zeolite membrane. An acidic environment was more favorable to the reduction of Cr(VI) and the breakthrough time reached 300 min for 4.7% breakthrough at pH 2. Both Yoon-Nelson and Bed Depth Service Time (BDST) models were found to agree well with the experimental results of Cr(VI) removal. The catalyst for CWPO of OII achieved the highest activity (OII conversion > 97%, COD removal ratio about 86.0%, respectively) after continuously ran for 240 min. Meanwhile, low iron leaching concentration (<3.5 mg/L) was detected in the treated effluent.

Multi-Layer Filters: Adsorption and Filtration Mechanisms for Improved Separation.

Filters made of cellulose fiber and perlite particles were prepared using a wet laying papermaking technique. Polyamide-amine-epichlorohydrin (PAE) was added to provide wet strength. Filters were prepared at two different total basis weights of 200 and 400 grams per square meter (gsm). Single and multi-layered filters were structured for each total basis weights. The effect of total basis weights and multi-layered structure on methylene blue adsorption and silicon dioxide (SiO2) particle filtration was investigated. Methylene blue adsorption was performed in two modes: constant pressure and constant flow rate. In both operation modes, the adsorption capacity of multi-layered filters was significantly higher (16–100%) than for single-layer filters at the same overall weight. The effect of layer separation was also characterized using polypropylene separators and tested under constant flow rate operation. Separators provided more effective methylene blue adsorption by generating a well-distributed flow. Filtration performance was quantified with 0.5 μm silicon dioxide particles under constant pressure conditions; this is to mimic bacteria rejection. Filtration capability of SiO2 particles was reduced slightly (12%) with decreasing individual filter layer thickness regardless of the multi-layered structure. Filtering polyethylene glycol (PEG) molecules with two different molecular weights was performed; however, no rejection was recorded. The filter internal pore structure was visualized by 3D-X ray computed tomography and the void fraction was quantified. 400 gsm single layer presented areas of low fiber density forming pores, while the pore volume decreased for thinner filter layers.

Effects of heat treatment temperatures on microstructures and mechanical properties of the chopped carbon fibres SiC composites

ABSTRACTA simple wet papermaking technique was used to fabricate chopped carbon fibre paper (Csf-paper) with random fibre orientation and self-supporting network structures in this work. The Csf-papers were laminated layer by layer and further infiltrated with PyC interface and SiC matrix via chemical vapour infiltration (CVI) to obtain Csf/SiC composites. The effects of heat treatment temperatures on microstructures, phase composition, and mechanical properties were investigated. Results showed that the Csf-paper has played a good self-supporting role and its fibres form a completely random fibre orientation in 2D plane. The fibres almost remained undamaged and unbroken during the CVI. Proper heat treatment could improve the mechanical properties. At 1200°C, the maximum values of flexural strength and Young's modulus reached about 306 MPa and 196.5 GPa, respectively. Meanwhile, compared with tape casting, reaction sintering and spark plasma sintering, composites fabricated by wet papermaking and CVI can improve the mechanical properties.