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We investigated the effect of pulping processes on the strength properties of bamboo paper. Bamboo was pulped by hand and by the kraft process. Handsheets were formed from the pulps obtained and their properties were measured before and after accelerated aging. The pulp made by hand had lower water retention and higher initial viscosity than the kraft pulp. Paper made from the hand-made pulp had considerably higher aging resistance than paper made from the kraft pulp. All the measurements revealed that acid-free paper made from the hand-made pulp retained its mechanical strength (especially folding endurance) better during accelerated aging than acid-free paper made from the kraft pulp. Retention of the folding endurance depended considerably on the retention of the zero-span tensile strength during sealed-tube aging. With the exception of zero-span tensile strength, hand-pulped and kraft-pulped acidic papers did not exhibit any significant difference in their mechanical properties. Although the paper made from the hand -made pulp had higher sheet strength than the paper made from the kraft pulp, both papers exhibited similar reductions in the surface pH during tube aging. Before and after accelerated aging, the paper made from kraft pulp produced by cooking at 170 °C for 90 min had higher intrinsic fiber strength than the paper made from kraft pulp produced by cooking at 160 °C for 60 min for both acid-free and acidic papers. [ABSTRACT FROM AUTHOR]

A conductive paper for shielding electromagnetic waves was produced by mixing pulp fibers with plated pulp fibers, obtained by subjecting disintegrated pulp fibers to electroless nickel plating to impart conductivity to the surfaces, and subjecting the resultant mixture to papermaking. The plated pulp fibers have surfaces covered with metal, and hence, the hydrogen bonds that pulp fibers generally possess do not contribute to the bonding between plated pulp fibers. For this reason, it has conventionally been difficult to manufacture paper from plated pulp fibers. To overcome this difficulty, a conductive paper was prepared from a mixture of plated and unplated pulp fibers. The conductivity of the formed conductive paper was improved by increasing the plated pulp fiber ratio. As a result, both the surface and volume conductivities increased, thus improving the shielding effectiveness against the electric field components of electromagnetic waves. Furthermore, to improve the electromagnetic shielding performance, conductive layers containing plated pulp fibers and insulating layers containing only pulp fibers were stacked on one another to form a multilayer conductive paper. In conductive paper with stacked conductive layers, increasing the number of conductive layers by two increased the electromagnetic shielding effect from 3 dB to 24 dB. A conductive paper with three conductive layers achieved a general electromagnetic shielding effect of about 30 dB at frequencies of 10 MHz to 1,000 MHz. [ABSTRACT FROM AUTHOR]

Suppression of the deterioration of acidic bamboo paper by the Bookkeeper process (BK) and the dry ammonia ethylene oxide process (DAE) was investigated. These deacidification processes reduce the acidity of both acidic bamboo and hardwood papers to pH 8, which is comparable to acid-free paper. Deacidified bamboo and hardwood papers had higher pHs than untreated papers after accelerated aging for one week at 100 °C in a sealed tube. Both deacidification processes preserved the mechanical properties (e.g., folding endurance and zero-span tensile strength) of bamboo papers after one week of sealed tube aging. In contrast, bamboo papers deacidified by BK and DAE processes exhibited a significance loss in tearing strength after one week of tube aging, compared with deacidified hardwood papers. The reduction in the tearing strength of deacidified bamboo papers depended considerably on the reduction in the degree of polymerization during sealed tube aging. Due to the rapid reduction rate of degree of polymerization during sealed tube aging for one week of bamboo papers deacidified by DAE process, such paper exhibited appreciably higher degradation rates than bamboo papers deacidified by the BK process. [ABSTRACT FROM AUTHOR]

The article presents a study on the rolling test method which is used to evaluate paper deterioration. The study analyzes the correlation between the rolling test and conventional mechanical measurements using paper samples of varying levels of degradation, which are rolled using cylinders of different diameters. The results reveal that samples from the second half of the 1800s are less flexible than samples from other periods, and that groundwood pulp is a potential cause of the deterioration.

Laboratory sheets prepared from bamboo and hardwood pulps were subjected to dry heat aging, moist heat aging, and sealed tube aging for different durations and the resulting changes in their physical properties related to paper degradation were evaluated. Unaged acid-free laboratory sheets prepared from bamboo pulp exhibited higher tearing strengths and zero-span tensile strengths than sheets prepared from hardwood pulp. However, bamboo sheets tended to degrade more rapidly than hardwood sheets in accelerated aging tests. In particular, acidic bamboo sheets aged faster than acidic hardwood sheets in the sealed tube aging test. The deterioration rate of bamboo paper depended considerably on the reduction in the degree of polymerization during aging. Tube aging gave higher degradation rates of the properties of both bamboo and hardwood papers than either dry heat aging or moist heat aging. [ABSTRACT FROM AUTHOR]

Making pulp fiber conductive is imperative to produce conductive paper. In this study, we experimentally investigate disintegrated pulp fibers electroless plated with nickel to make the fiber conductive. In conventional electroless nickel plating on plastic materials, adding the drying process after the surface activation and catalyst adsorption processes have made electroless plating on the fiber surface possible. Our observations of the cross section of plated pulp fibers and the analysis of its elements verify that a nickel film covering the fiber surface was formed. The plate film became thicker as the plating time and temperature increased. The DC electrical resistance of the plated pulp fiber decreased to 10¹ Ω, as the plating time and temperature increased. The AC impedance was converged between 10¹ Ω and 10² Ω as the measurement frequency increased, which verifies that conductivity can be maintained. [ABSTRACT FROM AUTHOR]

The addition of a bulking agent achieves the bulking of paper and increases the pore volume. In this study, the effect of adding bulking agents with various alkyl chain lengths (C, C, and C) on the bulk of paper, the sizing performance, and sheet wettability was evaluated. The bulking effect of a bulking agent with a short alkyl chain length (C) was large, and reduction in the sheet tensile strength was confirmed to be suppressed. Good sheet sizing performance was achieved when a bulking agent was used with an alkyl ketene dimer (AKD). When 0.1% or more of AKD was added, using a bulking agent with a shorter alkyl chain length increased the improvement in the sizing degree. Pyrolysis gas chromatography measurements of the amount of reacted AKD revealed that the addition of a bulking agent increased the AKD content of the sheet. The sheet contact angle measured by the two-liquid method tended to increase with increasing alkyl chain length. However, the sheet contact angle was not directly correlated with the Stöckigt sizing degree. By using 1% ferric chloride (FeCl) and 2% ammonium thiocyanate (NHSCN) aqueous solution, which are used for measuring the Stöckigt sizing degree, the time-dependent change in the contact angle on the paper sheet surface was measured to evaluate wettability. The Stöckigt sizing degree of paper sheets was found to be greatly influenced by the sheet wettability by NHSCN solution. In the case of 2% NHSCN aqueous solution, different samples exhibited large wettability differences. When 0.2% or less of AKD was added, the effect of the concentration on the contact angle was confirmed to be large at all NHSCN concentrations. [ABSTRACT FROM AUTHOR]

The article presents a study on the effects of deacidification/strengthening combinations on papers using magnesium carbonate (MgCO3) with cellulose derivatives including methylcellulose, carboxy methylcellulose (CMC), and ethyl cellulose. The study conducted tests using ligneous papers and acidic wood-free paper. It reveals that the most appropriate treatment to deacidify and strengthen the commercial papers is the combination of methylcellulose and MgCO3.

The utilization of recovered paper for high-grade paper such as printing, communication, and tissue papers has been limited because using recovered paper tends to reduce the quality of these papers. Therefore, despite an increasing recovery rate, the wastepaper utilization rate in Japan was still only 61.8% in 2008. In Japan, the regulations of the "Law Concerning the Promotion of Procurement of Eco-Friendly Goods and Services by the State and Other Entities" were strengthened in 2009 to counteract the practice exposed in the so-called "Wastepaper Camouflage Scandal". In order to assess the wastepaper pulp content in recycled paper, a new method using a fluorescence microscope is developed. As fluorescent whitening agents are commonly used to enhance the whiteness and brightness of paper, most recovered printing paper contains fluorescent whitening agents. Both visual observation and image analysis techniques were investigated to differentiate between virgin and wastepaper pulp fibers. Recycled handsheets were prepared to establish the fluorescence observation technique for evaluating the wastepaper content. More than 1,200 fibers should be counted to accurately determine the wastepaper content by this technique. The results obtained by the visual observation technique agree with image analysis of the recycled handsheets. The actual precision of the quantitative wastepaper pulp fiber analysis by the fluorescence observation technique depends on the wastepaper pulp content and the amount of fluorescent whitening agent in the recycled-content paper. [ABSTRACT FROM AUTHOR]

Activated carbon is proposed as a new use of wastepaper as an alternative to using it to make recycled paper. Waste kraft bag is considered to be a suitable raw material for activated carbon because of it has a low ash content. Small pellets of wastepaper that were extruded from a continuous kneader were carbonized in a nitrogen atmosphere and activated using carbon dioxide. The Brunauer-Emmett-Teller (BET) specific surface area of activated carbon prepared from waste kraft bag was 1,285 m2/g, which is higher than that of commercial activated carbons. The activated carbon prepared from wastepaper has a well-developed porous structure, particularly in the mesopore range. As a result, activated carbon with an iodine adsorption capacity of 1,400 mg/g was obtained from waste kraft bag. In this study, the amount of bisphenol A (BPA) that was adsorbed was determined to investigate adsorbability of activated carbon derived from waste kraft bag. Adsorption measurements were performed on solutions with concentrations from 0.1 gg/l to 100 mg/1. The activated carbon from waste kraft bag had higher BPA adsorbabilities than commercial activated carbons over a wide range of concentrations. [ABSTRACT FROM AUTHOR]

When the bulking promoter is added to pulp slurries at the wet end, the additive behaves like surface-active agent and partially prevents the formation of interfiber bonds in the handsheet. Therefore, an increase in paper thickness at the same basis weight could be performed. The tensile strength of the handsheets varied in proportion to the reduction of sheet density. Furthermore, considerable decreases in sheet density were observed for the acidic handsheets, compared with neutralized handsheets. The Page equation (1/T=1/F+1/B) was used to evaluate the strength contributions of single fiber and interfiber bond to tensile strength of handsheet. As a result, decreases in interfiber strength and only slight changes in zero-span tensile strength were obtained for both acidic and neutralized handsheets with addition of the bulking promoter. It was confirmed that the decrease in tensile strength of handsheet was dependent on the decrease in interfiber bond strength. Pore structures of the handsheets were characterized by mercury porosimetry. Addition of the bulking promoters caused increases in total pore volumes. Furthermore the major peak of control handsheet in the pore diameter 4 to 6µm region was broadened by addition of the bulking promoters. The light scattering coefficient of the handsheet reasonably increased because of its high porosity. Improvement of sheet thickness was confirmed by the SEM observation. The addition of the bulking promoters is capable of affecting not only in the interfibers but also in the pore structure of fiber wall. [ABSTRACT FROM AUTHOR]

The article focuses on a strengthening treatment for archives. The strengthening agents used in this treatment include methyl cellulose, carboxy methyl cellulose, hydroxy propyl cellulose and the deacidification agent, magnesium carbonate. The research revealed that strengthening of paper using methyl cellulose, carboxy methyl cellulose or hydroxy propyl cellulose improved the tensile strength, tearing strength and folding endurance of the paper and thereby, reveals the effect of the strengthening agent. The research also revealed that addition of magnesium carbonate to the strengthening emulsion results in simultaneous strengthening and deacidification.

Recycled pulps were treated with a rosin-alum internal sizing system, and handsheets were prepared from the sized pulp. These handsheets were treated with gaseous OsO4 in order to label carbon double bonds in rosin acids. They were then analyzed by using X-ray photoelectron spectroscopy. Handsheets prepared with recycled pulps containing fine fibers were found to have increasing concentrations of rosin sizes on their surfaces as the pulp was recycled more. This increase was not found in handsheets prepared from fine-free pulp. The fines having large surface areas were considered to adsorb many more particles of rosin sizes than did long fibers. The increase in rosin size concentration on the handsheet surfaces was caused by these fines generated in pulp recycling. About 30% of rosin sizes retained in rosin-sized handsheets were removed after the first recycling. Rosin sizes were almost completely removed by five recycling treatments of the handsheets. The decrease in rosin size concentration on the handsheet surfaces produced by recycling was similar to the decrease in total content. Sizing effects of the handsheets evaluated by the Stöckigt method were lost after the first recycling process, although rosin sizes remained to some extent both in the handsheets and on the handsheet surfaces. [ABSTRACT FROM AUTHOR]