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High bulk papers are attractive because they use less pulp but achieve properties suitable for applications in tissue, filters, and lightweight packaging. This study explores using hydroxypropyl methylcellulose (HPMC), a low-cost and renewably-sourced cellulose derivative, as a surface modifier for mechanical pulps to enhance paper properties. Two application methods were investigated: (1) pre-treatment by adding HPMC to the pulp dispersion and (2) post-treatment by spraying HPMC solution onto paper. Both pre- and post-treated handsheets exhibited improved tensile index and bulk concurrently, which is rarely observed. HPMC adsorbed to the fibre surface spontaneously improving fibre–fibre bonds through polymer entanglement, which led to higher tensile properties. Higher bulk values resulted from preventing fibre collapse during drying (i.e., maintaining open fibre lumens), attributed to the surface activity of HPMC and reinforcement of the fibre cell wall (supported by reduced kinks and curl index upon HPMC adsorption). X-ray tomography showed non-collapsed fibres and symmetric structures in handsheets from fibres pre-treated with HPMC, also suggesting improved cell wall strength and fibres that resisted pressure gradients. These findings indicate that HPMC as a paper additive is a practical and sustainable approach to reinforcing paper products, offering an alternative to high energy refining and oxidizing agents. This approach challenges the traditional trade-off between tensile index and bulk in pulp refining, emphasizing the potential of HPMC as a "green" surface modifier to enhance the strength of bulky papers. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The demand for eco-friendly packaging materials has urged researchers to look for alternatives to petroleum-based polymers. In this regard, paper-based products have turned out to be a promising choice; however, their weak resistance to water has limited their application. The use of various additives to enhance paper's moisture resistance is a common practice. However, considering the growing global agenda for sustainable development, the search for new bio-based paper additives has become increasingly important. This study investigated the potential synergistic impact of the addition of nanofibrillated cellulose (NFC) and chitosan additives (CHIT) to different fiber combinations to improve paper's properties, in particular, their wet strength. The efficacy of the additive application order was examined and was found to be crucial in achieving the desired outcomes. The results showed that incorporating CHIT after NFC enhanced the paper's tensile and burst indicators, as well as the paper stretch in the dry state, by 35–70%, 35–55%, and 20–35%, respectively. In addition, the tensile index and stretch in the wet state improved 9–13 times and 2.5–5.5 times over, respectively. The air permeability decreased 2.5–12 times over. These findings demonstrate that the sequential addition of the NFC and CHIT additives yield a greater enhancement of paper's properties than using each additive separately. [ABSTRACT FROM AUTHOR]

The present study deals with the valorization of corn stalks in an integrated processing strategy targeting two products: extracted hemicelluloses (HC) and papermaking fibers. Preliminary trials were conducted to assess the individual or the combined effects of biomass treatment on the quality of the obtained hemicelluloses and papermaking fibers. Depending on the hot alkaline extraction (HAE) conditions, the extracted HC had a xylan content between 44–63%. The xylan removal yield ranged between 19–35%. The recovery of HC from the extraction liquor and final black liquor was significantly affected by process conditions. The experimental approach continued with the study of HAE conditions on the obtained paper's mechanical properties. The optimization approach considered conserving paper strength properties while achieving an equilibrium with the highest possible HC extraction yield. The optimal values are sodium hydroxide concentration (1%), process time (33 min), and temperature (100 °C). The xylan content in the separated HC sample was ~55%. An extended extraction of HC from the resulting pulp under hot alkaline conditions with 5% NaOH was performed to prove the HC influence on paper strength. The xylan content in HC samples was 65%. The consequence of xylan content reduction in pulp leads to 30–50% mechanical strength loss. [ABSTRACT FROM AUTHOR]

Extending the use of mechanical pulp into non-traditional paper markets that requires moving towards producing high-bulk, porous paper grades with sufficient strength has gained intensive interest. This paper explores the potential of incorporating fiber fractionation with microfibril production to create high-bulk, porous, and strong enough material appropriate for a wide range of non-traditional mechanical pulp applications. Two different pressure-screen fractionation trials were conducted to fractionate a primary pulp into a long and coarse fiber stream (reject) and a fine and short fiber stream (accept). High-bulk, low-tensile sheets were obtained using the long and coarse reject fibers. The accept fibers were low-consistency refined at high specific energy to produce a microfibrilated cellulose (MFC) material and used to strengthen the high-bulk reject pulp sheets. The results illuminated that incorporating highly refined accept fibers having MFC-mimetic network into the paper structure could be a promising route to engineer the paper properties and extend the property range in comparison to low consistency refined whole pulp. Different series of handsheets were made and systematically studied by means of fiber length, fine percentage, bulk, tensile index, tensile energy absorption, Tear and burst indices, and freeness. Moreover, SEM micrographs were used to interpret the variations of paper properties. We believe that our results shed light on future mechanical pulp materials suitable for packaging and absorbency grades of paper that are high-bulk with sufficient strength for the specific application. [ABSTRACT FROM AUTHOR]

The demand for eco-friendly packaging materials has urged researchers to look for alternatives to petroleum-based polymers. In this regard, paper-based products have turned out to be a promising choice; however, their weak resistance to water has limited their application. The use of various additives to enhance paper’s moisture resistance is a common practice. However, considering the growing global agenda for sustainable development, the search for new bio-based paper additives has become increasingly important. This study investigated the potential synergistic impact of the addition of nanofibrillated cellulose (NFC) and chitosan additives (CHIT) to different fiber combinations to improve paper’s properties, in particular, their wet strength. The efficacy of the additive application order was examined and was found to be crucial in achieving the desired outcomes. The results showed that incorporating CHIT after NFC enhanced the paper’s tensile and burst indicators, as well as the paper stretch in the dry state, by 35–70%, 35–55%, and 20–35%, respectively. In addition, the tensile index and stretch in the wet state improved 9–13 times and 2.5–5.5 times over, respectively. The air permeability decreased 2.5–12 times over. These findings demonstrate that the sequential addition of the NFC and CHIT additives yield a greater enhancement of paper’s properties than using each additive separately.

The present study deals with the valorization of corn stalks in an integrated processing strategy targeting two products: extracted hemicelluloses (HC) and papermaking fibers. Preliminary trials were conducted to assess the individual or the combined effects of biomass treatment on the quality of the obtained hemicelluloses and papermaking fibers. Depending on the hot alkaline extraction (HAE) conditions, the extracted HC had a xylan content between 44–63%. The xylan removal yield ranged between 19–35%. The recovery of HC from the extraction liquor and final black liquor was significantly affected by process conditions. The experimental approach continued with the study of HAE conditions on the obtained paper’s mechanical properties. The optimization approach considered conserving paper strength properties while achieving an equilibrium with the highest possible HC extraction yield. The optimal values are sodium hydroxide concentration (1%), process time (33 min), and temperature (100 °C). The xylan content in the separated HC sample was ~55%. An extended extraction of HC from the resulting pulp under hot alkaline conditions with 5% NaOH was performed to prove the HC influence on paper strength. The xylan content in HC samples was 65%. The consequence of xylan content reduction in pulp leads to 30–50% mechanical strength loss.

High alkali impregnation (HAI) increases the total yield of softwood pulps following kraft cooking. This yield improvement is also maintained after oxygen delignification. This study evaluates how bleaching with either chlorine dioxide or hydrogen peroxide affects the final yield of samples obtained with standard and HAI. The chemical composition, viscosity, brightness, mechanical and morphological properties were studied. Compared to cooking after standard impregnation the yield improvement achieved by HAI was preserved in both types of bleaching sequences (2 % units for chlorine dioxide and 4 % units for hydrogen peroxide). The introduction of charged groups into the cellulose fibers was higher with hydrogen peroxide bleaching than with chlorine dioxide however, no significant impact was seen on the swelling or mechanical properties. The brightness was higher for the pulps bleached with chlorine dioxide compared with hydrogen peroxide. Hydrogen peroxide bleaching resulted in similar brightness development for both standard and HAI. Fibers bleached with chlorine dioxide had the highest curl index (16–17 %) compared to the fibers bleached with hydrogen peroxide (15 %). [ABSTRACT FROM AUTHOR]

The purpose of the present study is to offer an optimal model to predict the tensile index of the paper being consumed to make veneer impregnated with different weight ratios of modified starch (from 3.18 to 36.8%) to urea formaldehyde resin (WR) containing different formaldehyde to urea molar ratios (MR, from 1.16:1 to 2.84:1) enriched by different contents of silicon nano-oxide (NC, from 0 to 4%) using multiple linear regression (MLR) and adaptive neuro-fuzzy inference system (ANFIS) and compare the precision of these two models to estimate the response being examined (tensile index). Fourier-transform infrared spectroscopy (FTIR) and transmittance electron microscopy (TEM) were also used to analyze the results. The results of studying the adhesive structure using FTIR analysis showed that as the WR increased to the maximum level and MR increased to the average level (3%), more ether and methylene linkage forms due to cross-linking. TEM analysis also indicated that if an average level of silicon nano-oxide is applied, there will be more cross-linking due to the more uniform distribution and suitable interactions between the adhesive and nanoparticles. The modeling results showed that the ANFIS model estimates have been closer to the actual values compared to the MLR model. It can be concluded that the model offered by ANFIS has a higher potential to predict the tensile index of the paper impregnated with the combined adhesive of UF resin and modified starch. However, the MLR model could not offer a good estimate to predict the response. According to the preferred approach to predict the most effective property of resin coated paper, modelling would be useful to the research community and the results are beneficial in industrial applications without spending more cost and time. [ABSTRACT FROM AUTHOR]

Disposal of large volumes of textile waste is an escalating problem for textile industries. Sisal spinning industry is the one of the textile industries releasing large volumes of textile waste in the landfills. The rising costs, and reduction of available space together with increasing stringent environmental measures are making burying and land filling of textile waste, a declining option. This study therefore explores recycling options where the potential of using sisal fiber waste produced during sisal spinning processes as raw materials for the production of paper pulp was investigated. Sampling was done at 21stCentury Holdings Limited allocated at Chang'ombe industrial street Dar es Salaam mainly dealer of sisal yarns production. Materials were prepared and cut into small pieces of about ½ inches to reduce the fiber into unit lengths so as to achieve pulping required performance. Pulping process was achieved through Soda pulping techniques with two different effective alkali charges (EA-20% and EA-24%) for 240 minutes under maximum temperature 140°C, and liquor to fiber ratio 4:1by using Mathis Labomat dyeing Machine. The kappa number obtained was (25.5, 34.5) for material treated under EA 24% and EA 20% respectively, Percentage pulp yield were (47.1, 54.4) for EA 24% and EA20% pulp respectively. Freeness (630CFS, 555CSF) after refining at 4500 rpm. Finally, the resulting pulp was used for hand sheet making and the sheets were tested for their mechanical properties; Grammage (61.1, 61.1) g/m2, Tensile index (9.9, 22.3) Nm/g, Tear index (13.3, 17.4) Nm2/g, burst index (1.7, 3.7 and 1.6) kPa.m2/g and Elongation at break (2.02, 2.22) % for EA24% pulp, EA20% pulp respectively. The findings shows that sisal fiber wastes have a promising potential for paper pulp production compared to other non-wood raw material. [ABSTRACT FROM AUTHOR]

This study investigated whether the yield improvement after high alkali impregnation (HAI) is maintained after oxygen delignification and whether the potential of oxygen delignification to increase the mechanical properties is affected by high alkali impregnation. The yield improvement achieved by high alkali impregnation (1 %) was preserved after oxygen delignification, particularly of glucomannan. The total fiber charge and swelling increased after oxygen delignification regardless of the type of impregnation in the cooking step. The tensile index improvement obtained by oxygen delignification was retained if this was preceded by high alkali impregnation. The stiffness index was higher and elongation slightly lower after HAI impregnation than after a standard (REF) impregnation. Fibers obtained through high alkali impregnation seem to be slightly less deformed and slightly wider than fibers obtained after a standard impregnation. [ABSTRACT FROM AUTHOR]

The pulp and paper industry is increasingly seeking a sustainable and conscientious development, minimizing the environmental impacts caused by it. Therefore, reducing efficiently the number of stages used in the bleaching process can mean less consumption of water and chemical reagents, contributing to the reduction of harmful waste to the environment. Thus, this study sought to evaluate the pulp quality and some physical-mechanical properties (smoothness, tear and tensile indexes) of two new bleaching sequences A*DP and A*E*DP and compare them with the reference D0(E+P)D1P. To do so, industrial eucalyptus Kraft pulp pre-delignified with oxygen was used. The bleached pulp was refined to 1200, 1800 and 2400, in PFI mill and tested according to TAPPI standards to determine smoothness, tear and tensile indexes. Based on the results obtained, it was verified that the sequences studied are viable for using in bleaching plants, which allowed a reduction in the chlorine dioxide consumption and presented satisfactory smoothness, tear and tensile indexes for paper. [ABSTRACT FROM AUTHOR]

In this study, tunicate cellulose nanocrystals(tCNC) were investigated as a filler added to bleached kraft pulp. First, tCNC were prepared through bleaching and acid hydrolysis. The structure, morphology, crystallinity, and particle size and zeta potential of the tCNC were characterized by Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and a malvern particle sizer, respectively. Second, kraft pulp with a consistency of 10% was refined to 42 °SR through a PFI refiner. Then 60 g·m-2 handsheets were prepared from this pulp. Prior to preparing the handsheets, tunicate nanocellulose was thoroughly mixed into the pulp at four gradients:0.3%, 0.6%, 0.9%, 1.2%, and 1.5%. Cationic polyacrylamides(CPAM) were added to the pulp slurry as a retention agent. A control experiment was set up accordingly. The effects of tCNC addition on the tearing, tensile, burst, air permeability, and optical properties of the handsheets were evaluated. The results indicated that the maximum increase in the tear index was 12.00% when tCNC was added 0.6%. The tensile index reached its maximum value when tCNC was added at 0.6%, with an increase of 12.04% compared to pure pulp sheets. The tensile index increased by 16.55%. In this experiment, nanocellulose prepared from a mantle sea animal was used for the first time as reinforcing filler in papermaking, which has greatly extended the application of tCNC in the enhancement of paper strength. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The purpose of the present study is to offer an optimal model to predict the tensile index of the paper being consumed to make veneer impregnated with different weight ratios of modified starch (from 3.18 to 36.8%) to urea formaldehyde resin (WR) containing different formaldehyde to urea molar ratios (MR, from 1.16:1 to 2.84:1) enriched by different contents of silicon nano-oxide (NC, from 0 to 4%) using multiple linear regression (MLR) and adaptive neuro-fuzzy inference system (ANFIS) and compare the precision of these two models to estimate the response being examined (tensile index). Fourier-transform infrared spectroscopy (FTIR) and transmittance electron microscopy (TEM) were also used to analyze the results. The results of studying the adhesive structure using FTIR analysis showed that as the WR increased to the maximum level and MR increased to the average level (3%), more ether and methylene linkage forms due to cross-linking. TEM analysis also indicated that if an average level of silicon nano-oxide is applied, there will be more cross-linking due to the more uniform distribution and suitable interactions between the adhesive and nanoparticles. The modeling results showed that the ANFIS model estimates have been closer to the actual values compared to the MLR model. It can be concluded that the model offered by ANFIS has a higher potential to predict the tensile index of the paper impregnated with the combined adhesive of UF resin and modified starch. However, the MLR model could not offer a good estimate to predict the response. According to the preferred approach to predict the most effective property of resin coated paper, modelling would be useful to the research community and the results are beneficial in industrial applications without spending more cost and time.

Hybrid paper sheets were prepared by applying a thin coating layer of cross-linked polydimethylsiloxane (PDMS) and inorganic particles onto Whatman Grade 1 filter paper substrates. Several coatings with different inorganic particle contents and types were applied onto the paper substrates to investigate the effect of the variation in the coating formulation on the (i) wetting, (ii) water barrier properties, (iii) air barrier properties, (iv) surface roughness, and (v) mechanical properties of the samples. It was revealed that the superhydrophobic hybrid paper sheets with significantly low air permeability and high water barrier properties could be prepared which is an indication that the method proposed can be used for the preparation of packaging materials. [ABSTRACT FROM AUTHOR]

Abstract Indigenous plants are widely abundant in Mauritius and if made proper use of, these renewable plants can contribute largely to the local economic sector. This paper assesses the suitability of producing eco-friendly and biodegradable papers using low-cost raw materials by means of fibre from Pandanus utilis’ leaves commonly known as ‘Vacoas’. The leaves were used along with Arundo donax or wastepaper to manufacture composite paper samples in the ratios of 20:80, 40:60, 60:40, 80:20 and 100:0. Chemical pulping was done through Kraft process for a period of 1.5 h at a concentration of 14 wt% NaOH and 4 wt% Na2S at 90 ± 2.5 °C. The mean thickness of the papers was determined to be 0.261 ± 0.027 mm. It was found that the 100% Vacoas fibres had the highest absorbency rate of 1.8 ± 0.5 s followed by the composite A. donax and Vacoas fibre (1.8 ± 0.3 s). The most abrasion resistant paper which also demonstrated the highest burst index of 0.63 kPa m2 g− 1 and tensile index 11.8 N m g− 1 was observed to be that of 100:0 Vacoas fibre paper requiring 35 turns to get abraded followed by the P. utilis and A. donax mix where the 80:20 fibre ratio revealed a high bursting index of 0.45 kPa m2 g− 1 requiring 25 turns to get abraded while 40% P. utilis and 60% A. donax had a high tensile strength of 11.9 N m g− 1. Vacoas to wastepaper mix ratios of 20:80 and 40:60 were found to have the highest mean recovery angles of 61.3 and 59.6°, respectively.

During the manufacture of low basis weight tissue paper, it is difficult to efficiently use the dry strength agent (DSA) because a large amount of DSA adsorbed fines releases in forming roll by centrifugal forces. In this study, cationic polyvinylamine (C-PVAm) was used as a DSA in an environment where the retention of fines was weak. Addition of C-PVAm to the thermomechanical pulp (TMP) or TMP mixed with softwood bleached kraft pulp (SwBKP) improved the turbidity of filtrate from sheet former, however, the strength of handsheet paper was similar to that without C-PVAm. When C-PVAm was selectively added to SwBKP as much as 4 %, the tensile index could be improved by approximately 10.6 % without changing the retention of fines. In addition, C-PVAm added before the beating of SwBKP showed better results than C-PVAm added after the beating in terms of fines retention, tensile index, and formation. In particular, the tensile index was improved about 7.7 % by adding of C-PVAm 4 % as is before beating of SwBKP. Consequently, it was found that C-PVAm with a high reaction rate can be added before beating of SwBKP to improve the physical strength. [ABSTRACT FROM AUTHOR]

In this research, the effect of adding precipitated calcium carbonate filler combined with nanocellulose as reinforcement was examined to compensate the strengths loss of papers made of bagasse pulp. About 2 % of nanocellulose based on oven dry fibers suspended in water with 0.1 % consistency homogenized by ultrasonic was added to the pulp having 15 % PCC filler and was compared with the same sample without nanocellulose and base pulp (without any additives). Cationic polyacrylamide retention agent was added to the pulp suspension at the constant level of 0.14 % based on oven dry fibers. Statistical analysis of results revealed that the drainage time increased by adding of PCC and nanocellulose system to the bagasse pulp suspension. Addition of nanocellulose has enlarged filler particle retention due to the formation of adhesive flocs. Prepared SEM images from paper samples confirm filler particles flocculation, larger filler retention and their better distribution in paper network. Moreover, in papers filled by PCC and nanocellulose with roughly equal similar opacity and brightness, loss of strength characteristics due to adding of filler has been compensated. Although relatively higher drainage time of this pulp suspension is a substantial limitation, but pretreatment of filler with nanocellulose prior to its addition to the pulp can be investigated as a promising alternative.

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Increasing filler content in paper products and saving fiber resources are the permanent goals in paper industry. In this work, precipitated calcium carbonate and cellulosic fiber were refined in PFI mill so as to improve the paper strength and optical properties. Results showed that co-refining method deliver nine percent higher in filler content than regular filling method when the paper tensile index was similar ( 26 ~ 28 N • m/ g) . In addition, light scattering coefficient was also enhanced by co-refining. The images obtained by scanning electron microscopy implied that particle breakage and formation of filler-fiber composite during co-refining help to improve paper strength and optical properties. [ABSTRACT FROM AUTHOR]

The objective of this investigation is to analyze and model tensile index. Two approaches are used, one based on training and validation data, while the other novel approach tests models using all possible combinations of data points. This approach is focused on small data sets which have here been obtained from nineteen pulp samples at different refining conditions in a full-scale TMP production line with a CD-76 refiner as a primary stage. From each pulp sample twenty handsheet strips for tensile index measurements were performed. Initially, specific energy and the external variables (dilution water feed rates and plate gaps) are used as predictors in a modeling approach based on an adjusted R 2 {R^{2}} approach. Thereafter, the resulting models are compared with a combination of specific energy and internal variables (primarily consistencies) obtained from temperature measurements inside the refining zones using a soft sensor concept. It is found that specific energy and internal variables as predictors outperform the external variables when estimating tensile index. [ABSTRACT FROM AUTHOR]

The objective of this study was to understand the influence of bleaching on % residual lignin, water retention value, brightness and morphological properties of Subabul heartwood and sapwood pulps. The second aim was to compare the properties of unbleached and bleached handsheets with respect to tensile index and fractography. Screened wood chips of Subabul were subjected to kraft cooking (165 °C, 3 hours) followed by ECF bleaching and refining. When unbleached handsheets were compared, higher tensile index was found for sapwood sheets (29.8 N.m/g) than heartwood sheets (12.8 N.m/g). Therefore, it is recommended to use unbleached sapwood sheets for packaging grade applications. The bleached pulps have exhibited negligible residual lignin (0.1 %), higher water retention value (∼21) and higher brightness (88 %) compared to unbleached pulps. Subsequently, the bleached heartwood sheets revealed higher tensile index (∼7 fold) and higher modulus of elasticity (∼2.7 fold) compared to unbleached heartwood sheets. For printing grade applications bleached sapwood and bleached heartwood pulps are equally recommended, because no differences were observed in their pulp and sheet characteristics. [ABSTRACT FROM AUTHOR]

Deinking is the process of removing and separating ink from printed paper fiber. Large quantities of chemicals are used in the traditional deinking process in the paper industry. This is not only expensive, but the use of chemicals in large quantities also leads to many environmental problems. To reduce the chemical usage, one eco-solution is to use enzymes as deinking agents. In this article, an enzymatic newspaper deinking using a lignocellulase cocktail consisting of a cellulase from Actinobacillus sp. and recombinant xylanase from Geobacillus thermoleovorans IT-08 expressed in Escherichia coli DH5α (namely pTP-510) is reported. In order to increase the brightness of the deinked paper, a laccase from the wild type fungus Aspergillus sp. was added to the enzyme cocktail. The ratio of cellulase to xylanase in the cocktail was 4:1 and the laccase activity was varied. To assess the deinked paper quality, its brightness, strength, and surface profile were analyzed. The results showed that the addition of laccase 0.291 U to the enzyme cocktail leads to a brightness level of 60.4 % (ISO 2470), which exceeds the SNI 14-0091-1998 standard of 55 % (ISO 2470). The condition for tensile index was 25.36 Nm/g (ISO 1924/2), which is greater than the SNI 14-0091-1998 standard of 21.5 Nm/g (ISO 1924/2). Moreover, scanning electron microscopy (SEM) revealed that the surface of the enzymatically deinked paper is more tenuous than the control. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Because there is a lack of wood resources in many countries, this work focused on pulp and paper production from the waste and agricultural residues of non-wood plants. The work aimed to pulp the nitrate-alkaline of black mustard (Brassica Nigra L.) and camelina (Camelina Sativa L.). The black mustard and the camelina were selected due to the expanding planted areas of these crops in the Czech Republic. To characterize the chemical composition of black mustard and camelina, cellulose, lignin, ash, and extractives were determined. Raw alpha-cellulose, beta-cellulose, and gamma-cellulose were also measured. The results showed that the content of lignin in non-wood plants is lower than that in softwoods. The cooked pulp was characterized by the delignification degree–Kappa number. Additionally, handsheet papers were made for selected samples of pulp. The handsheet papers were characterized by tensile index, breaking length, and smoothness and compared with commonly available papers.

The objective of this study is to analyze and foresee potential outliers in pulp and handsheet properties for larger data sets. The method is divided into two parts comprising a generalized Extreme Studentized Deviate (ESD) procedure for laboratory data followed by an analysis of the findings using a multivariable model based on internal variables (i. e. process variables like consistency and fiber residence time inside the refiner) as predictors. The process data used in this has been obtained from CD-82 refiners and from a laboratory test program perspective, the test series were extensive. In the procedure more than 290 samples were analyzed to get a stable outlier detection. Note, this set was obtained from pulp at one specific operating condition. When comparing such "secured data sets" with process data it is shown that an extended procedure must be performed to get data sets which cover different operating points. Here 100 pulp samples at different process conditions were analyzed. It is shown that only about 60 percent of all tensile index measurements were accepted in the procedure which indicates the need to oversample when performing extensive trials to get reliable pulp and handsheet properties in TMP and CTMP processes.

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract The present study was conducted to form polysaccharide-based multilayers of cationic starch (CS)/anionic starch (AS), and CS/carboxymethyl cellulose (CMC) on broke chemi-mechanical pulp (BCMP) fibers. It aimed to examine the buildup of CS/AS and CS/CMC polyelectrolyte multilayers (PEM) on the fibers surface, and explore the effects of PEM formation on the properties of the resulting papers. The assembly of PEM was analyzed by using zeta (ζ-) potential, water retention value (WRV), SEM micrographs, and paper properties such as thickness and strength. The results of ζ-potential inversions indicated successful constitution of PEM on the BCMP fiber surface by assembling CS/AS or CS/CMC multilayers. Further, larger ζ-potential variations occurred in depositing CS/CMC PEM, due to more charge of CMC, which presumably formed a layer with greater potential of absorption. Based on the SEM images, the surface of PEM-treated fibers was rougher, compared to the untreated fibers due to the coating with starch. Furthermore, the PEM fabrication resulted in creating fibers with higher degree of WRV, which was consistent with the significant improvement of the sheet strengths. Finally, the strength enhanced papers made from PEM-treated fibers with tensile index of about 37.33 ± 1.47 N m/g vs 22.24 ± 1.23 N m/g or 11.60 ± 0.57 N m/g for the papers made from original CMP and untreated BCMP fibers, respectively, may diminish the challenges related to web breaks in the paper machine conveying BCMP broke fibers. Highlights • LbL technique was examined to fabricate polysaccharide-based PEMs on BCMP fibers. • Zeta potential oscillations confirmed the success of PEMs forming onto the fibers surface. • PEMs assembly conferred upon fibers with higher hydrophilic groups, increased degree of WRV. • SEM characterization exhibited remarkable fibers joints and compacted structure in the resultant sheets. [ABSTRACT FROM AUTHOR]

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The objective of this study was to evaluate the mechanical and optical properties of paper made from alkaline sulfite anthraquinone and methanol (ASAM) unbleached pulp from bamboo (Gigantochloa scortechinii). The bamboo pulps were beaten using a PFI mill at 10,000 revolutions. To determine the properties of unbleached bamboo ASAM paper, handsheets with a density of 60 g/m2 were formed with 14 to 18% NaOH, 80/20 Na2SO3/ NaOH, 0.1% AQ, 0.5% EDTA, and 15% methanol pulping conditions. Pulping at 18% NaOH for 120 min cooking time produced paper with properties of 24.8 Nm/g and 43.02% for the tensile index and ISO brightness, respectively. Cooking at 16% sodium hydroxide for 90 min rendered the best results for mechanical and optical properties, with results of 20.86 Nm/g, 22.64 mN.m2/g, and 39.32% ISO value for the tensile, tear indices, and brightness, respectively. High quality bamboo paper produced by the ASAM pulping process was beneficial for producing highly durable paper and paperboard.

Comparison of industrial and laboratory pulps from Pinus radiata showed higher energy requirement and lower tear index at the same tensile strength in the case of industrial pulps. Chemical differences between pulps were negligible and cannot explain the strength differences observed. Morphology of the fibers changed during processing with an increase in kinks and curls for industrial pulps. Increased twists and wrinkling in mill fibers were observed based on scanning electron microscopy images. Results from water retention value and fiber saturation point measurements showed reduced water holding ability of industrial fibers. Simons’ stain and hydrogen nuclear magnetic resonance confirmed a higher proportion of macropores in the fibers of industrial compared to laboratory pulps. Evidence supports the presence of both micropore closure and creation of new mesopores and macropores during industrial processing. A combination of fiber damages, porosity changes, and induced deformations seems to play the main role in the lower strength properties of industrial pulps when compared to laboratory pulps.

The accelerated thermal ageing process was organized to compare the performance of oils before and after being subjected to oil reclamation. New mineral oil of the same brand was used as a base line measurement for evaluating the performance of the reclaimed oil with and without inhibitor. Samples consisting of oil, paper and metallic catalysts including zinc, copper, aluminum, and iron were aged at 115 °C in an air circulating oven for 250, 500 and 750 hours. A free radical reagent, 2.2 diphenyl-1-picrylhydrazyl (DPPH), was used to determine the relative concentration of free radicals in the oil samples. Key ageing indicators, namely free radical scavenging activity (RSA), relative content of dissolved decay products (DDP), turbidity, total acid number (TAN), interfacial tension (IFT), dielectric dissipation factor (DDF), and absolute water content for oil, and low molecular weight acids (LMA), and tensile index (TI) for paper, were measured regularly. It was found that the performance of the reclaimed oil is definitely better than the non-reclaimed oil, and is highly likely competitive with new mineral oil with the same brand. The results show that after a long run of the ageing process, RSA and DDP of the reclaimed oil without inhibitor are respectively more and less than that of the new oil. In addition, slower reduction of TI of paper aged in the reclaimed oils corroborates the theory that the paper degradation in a transformer can be reduced through oil reclamation. [ABSTRACT FROM AUTHOR]

Surface properties of cellulosic fibers can be modified by Layer-by-Layer (LbL) technique. Cotton fibers are one of important non-wood and industrial cellulosic resources in the world. Cotton linters is produced as a by-product accompany with cotton fibers which is used as a significant cellulosic sources in paper industry for producing durable paper. In this research, the influence of alternate adsorption of cationic chitosan and anionic Nanosilica on modification of fiber surface of cotton linter was investigated. The adsorption of materials on cellulosic fibers was analyzed via electrolyte titration. Experiments were conducted at pH≈3-4 for formation of cationic layer and pH≈9-10 for formation of anionic layer applying stirring rate of about 750rpm, for15 minute deposition time to construct 1 to 3 layers. Hand sheets of about 60 g/ m2 basis weight were made form modified pulp fibers prepared by multilayering of chitosan and nanosilica, then their structural properties and bonding ability were evaluated. Bonding ability of fibers was improved by polyelectrolyte multilayering (PEM) on the surface of cotton linter fibers which was visualized by Field Emission Scanning Electron Microscopy (FESEM).The results showed that apparent density and also bonding ability was improved in the treated fibers because of the increased electrostatic attraction between polycation and anion sites existed on the fiber surface. Apparant density of paper was improved remarkably compared to the untreated fibers. Tensile index of the sheet was increased about 16% with consecutive adsorption onto the cotton linter fibers compared to untreated fibers. Formation index of paper was slightly deteriorated after polyelectrolytes multilayering.

Alkaline peroxide mechanical pulp (APMP) is a newly emerging high yield pulp (HYP) with numerous advantages. However, the drawback of the alkaline peroxide mechanical pulp from untreated plant biomass is its poor network strength. In this work, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC) modification was proposed to enhance pulp network strength by fiber surface modification that could enhance fiber bonding. Three factors were analyzed by response surface methodology (RSM) to optimize treatment conditions based on factorial designs. The results showed that the optimal conditions were CHPTAC dosage of 0.8% (oven-dry pulp), NaOH dosage of 0.1% (oven-dry pulp), and pulp concentration of 8%. The modified pulp fibers were characterized by elemental analysis, charge density analysis, Fourier transform infrared spectroscopy (FTIR), thermal gravity analysis (TGA), and internal bond strength analysis, as well as zero span tensile analysis. The physical strength of the modified APMP pulp was increased in terms of tensile index, tear index, and burst index. After modification, the tensile index, tear index, and burst index increased by 35.3%, 29.2%, and 16.7% respectively. The internal bonding strength increased by 144.4%; however, the increase of zero span tensile index of modified pulp fibers was insignificant. [ABSTRACT FROM AUTHOR]

The widespread availability of banana pseudo stems which do not have considerable commercial value in the country presents a potential source of non-wood raw material for paper production. This investigation determined the suitability of using banana fiber for wrapping paper production. Banana fiber was used with sugarcane bagasse and wastepaper to produce paper in 20:80, 40:60, 60:40 and 80:20 ratios. Banana and sugarcane bagasse were chemically pulped using 12% NaOH and 4% Na 2 S for 1.5 h. The mean thickness of the papers were 0.263 ± 0.04 mm. 100% banana paper and 100% bagasse paper showed nearly similar water absorbency (2.15 s and 2.17 s) and were 2.25 times more than paper from 100% wastepaper. Highest tensile index was evidenced by banana paper with 20% wastepaper (29.4 Nm/g). For banana-bagasse mix-ratios, 20% bagasse demonstrated highest tensile index (16.04 Nm/g). 100% banana paper produced a tensile index of 18.97 Nm/g. Highest bursting index was from banana paper with 20% wastepaper mix (2.00 kPa m 2 /g). For banana-bagasse mix-ratios, 20% bagasse addition showed the greatest bursting index (0.88 kPa m 2 /g). 100% banana paper produced a burst index of 1.05 kPa m 2 /g. Highest abrasion resistance was 180 turns which was demonstrated by 100% banana paper. 20% mix bagasse and 20% mix wastepaper demonstrated the greatest abrasion resistance with 136 turns and 120 turns respectively. 20 ̶ 40% of wastepaper (5.4 ̶ 5.8% weight loss) and 10 ̶ 30% bagasse (10.0 ̶ 15.5% weight loss) were categorised as optimal mix percentages in the pulp mix for their minimal weight losses. [ABSTRACT FROM AUTHOR]

The main goal of this work was to reinforce softwood pulp (SP) with bacterial cellulose (BC) to generate a sustainable biocomposite. BC is a nanocellulose, which was anticipated to increase interfacial adhesion between the cellulosic fibers and BC. The organism used was Gluconacetobacter xylinus , which was incubated in a static Hestrin-Schramm culture at 28 °C for 14 days. The specimens of BC, SP and the reinforced SP with BC were characterized using X-ray diffraction (XRD), FT-IR, FESEM, and physico-mechanical testing. The crystallinity index was found to be 83 and 54% for BC and SP, respectively. FT-IR spectra showed that the composition of BC was fully different from that of SP fibers. Based on FESEM images, one can conclude that BC and softwood fibers do form a good combination with a nonporous structure. BC fibers fill in among the softwood fibers in the sheet. The physical and mechanical properties showed that as the dosage of BC increased, the properties of tensile index, tear index, and burst index greatly improved, while the porosity and the elongation decreased. The reason for the improved mechanical properties can be attributed to the increase of interfibrillar bonding which reduced porosity. This would be due to the high aspect ratio of BC that is capable of connecting between the cellulosic fibers and BC nanofibers, enhancing a large contact surface and therefore producing excellent coherence. This study suggests that BC could be a promising material for reinforcing composites at low loading. [ABSTRACT FROM AUTHOR]

This research identified suitable conditions to fabricate pulp fibers for paperboards and medium density fiberboards (MDF) from the bagasse of sugarcane ( Saccharum officinarum ) and the empty fruit bunch (EFB) of oil palm ( Elaeis guineensis ). First, the effects of chemical pretreatments at 121 °C and pressurized refining under steaming conditions were studied in regards to the thermomechanical pulps. The optimal conditions to achieve the highest paper strength properties of the EFB pulp involved pretreatment with 2% NaOH for 2 h and refining at 0.7 MPa of pressure at 165 °C. The sugarcane bagasse (SB) pulp properties could not be improved by chemical pretreatment, while the EFB pulp properties clearly benefited from such pretreatment. Second, the effects of dry and wet blowing methods after pressurized refining on the fiber properties were examined. The strength properties of the half-dried SB and EFB pulps with 55% solid content were slightly higher than those of their wet counterparts. These results clearly suggest that SB and EFB can be promising refined fibers for paperboard and MDF preparation. Third, MDF was made from dried EFB refined fibers with 92% solid content by dry processing, and suitable properties for actual use were obtained. [ABSTRACT FROM AUTHOR]

To study the possibility of using plant Silybum marianum in paper industry, its stem yield potential, chemical properties, fiber indices and pulping was evaluated. Mean value of fiber length and diameter of Silybum marianumstem harvested in early June, were calculated 178 and 3.5 cm, respectively. Dry weight of whole stem determined 4710 kg per hectar. Mean value of fiber length, diameter, cavity diameter and wall thickness were obtained 1194, 16.06, 9.06, and 3.66 μm, respectively. Raunkel, flexibility, and slenderness ratios of its fibers were determined 80.83, 56.39, and 74.37, respectively. Results of chemical analysis showed that the stem comprises %70.35 holocellulose, %39.25 cellulose, %13.13 lignin, %3.09 acetone-soluble, %18 hot water-soluble extractives, and %11/85 ash. Soda pulp was obtained at 165 °C pulping time, 25% alkaline and 10:1 ratio of liquor to chips. Results of pulping showed that with increasing of pulping time from 30 to 210 minutes, the kappa number and yield decreased from 77.32 to 32.13 and 43.6 to 36.5, respectively; whereas accepted pulp yield (passed from 20 mesh) increased from 17.4 to 35.5% paper made of pulp with kappa number 32 had 36.82 Nm/g tensile index, 3.76 km breaking length and 1.75 Kpa.m2/g burst strength. In general, achieved results have shown that the present studied species could be regarded more for papermaking because of the suitable fiber biometrical and chemical properties as compared to other non-woody plants.

Chemi-mechanical pulping was evaluated as a potential way to prepare sugarcane bagasse fibers for papermaking. Cellulose, lignin, ash, and extractives soluble in alcohol-acetone were measured as 55.75%, 20.5%, 1.85%, and 3.25%, respectively. Fiber length, diameter, lumen cavity, and cell wall thickness were measured as 1.59 mm, 20.96, 9.72, and 5.64 µm. The chemi-mechanical pulping conditions were selected as follows: three charging levels of 10, 15, and 20% sodium sulphite, and three pulping times of 20, 30, and 40 minutes after reaching the pulping temperature. Pulping temperature was held constant at 165 C. Different pulping conditions resulted in pulp yields between 65.38 and 84.28%. The highest yield (84.28%) was obtained using a treatment combination of 20 minutes pulping time and 10% sodium sulphite. The lowest yield (65.38%) was related to 40 minutes pulping time and 20% sodium sulphite. Pulps were refined to 300 ± 25 mL CSF, 60 gm-2 handsheets were made, and then strength indices and optical properties of the handsheets were measured. The results showed that 20% sodium sulphite, 40 minutes pulping time, at 165 ºC can be considered as the optimum pulping conditions for bagasse CMP pulping. Tensile, tear, and burst strength indices, as well as the opacity of this pulp were measured as 39.59 Nmg-1, 6.66 mNm2g-1, 2.1 KPa m2g-1, and 95.35%, respectively.

A number of thin biomaterials were prepared via a wet formation method from seven different unbeaten plant fibers without using any chemical additives. It is noted that sheets made with short fibers (Flax-B: 0.32 mm and Straw-UB: 0.36 mm) and high fine content (Flax-B: 9.77% and Straw-UB: 10.64%) showed higher tensile index values (Flax-B: 27 Nm/g and Straw-UB: 25 Nm/g) than those made from long fibers. Despite having the longest fibers (1.11 mm) in studied samples, the tensile index values of sheet sample made from Pine-S-UB was just 12 Nm/g, which is just half of short-fibered (0.36 mm) straw sheets. Air permeability of sheets made from Pine-S-UB and Straw-UB were 5322 and 917 ml/min, respectively. Densities of the same sheets in the same order were 493 and 539 kg/m3. It is concluded that long cellulose fibers actually produce bulky materials with limited interfiber contacting areas, while short ones give biocomposites with higher density values indicating a firmly compacted internal structure in the case of utilizing plant fibers without beating and refining. Results would be usable when producing biocomposites from plant fibers via wet formation followed by various resins and polymer moldings.

Changes of the pore structure of recycled fibers and the strength properties of papers produced by old corrugated container (OCC) recycled fibers were studied, after they were subjected to different stock preparation and papermaking processes. In this paper, the effects of beating, sizing, pressing, and drying on fiber properties were investigated, and the porous structure of fibers was analyzed by nitrogen adsorption technique. The results showed that beating, pressing, and other physical processes significantly influenced the fiber properties, whereas the effects of sizing were minor. Significant changes of water retention value (WRV), crystallinity index, and paper strength were observed after those processes. Further, an effort has been made to show relationships between pore structure and macroscopic properties (WRV, crystallinity index) of recycled fibers.

Two morphologically different pulps, a long-fiber jute pulp from a soda-AQ process and a short-fiber Trema orientalis pulp from a kraft process, were evaluated and compared for their reinforcing potential. T. orientalis pulp needed less beating energy than jute pulp at the same drainage resistance. Addition of jute fiber pulp to the T. orientalis pulp increased tear strength. Sheet density of pulp blends was increased with the increase of beating degree of both pulps and the proportion of T. orientalis pulp. Tensile index and burst index of blended pulp were increased when the beating degree and proportion of T. orientalis pulp increased.

Oxidative treatments, without and with assistance of a Laccase-Mediator System (LMS), were characterized in relation to their effects on the chemical composition and strength properties of the fibrous fraction of an unbleached recycled softwood kraft pulp. The LMS, composed of a Trametes hirsuta laccase extract and 1-hydroxybenzotriazole (HBT), was applied on the fibrous fraction of a recycled pulp at low consistency under continuous stirring and oxygen bubbling. Control treatments adding neither the enzyme nor the mediator were also considered. The LMS treatment caused a partial reversion of the detrimental effects of hornification. A considerable increase in the amount of carbonyl groups on the lignin structure was observed as a result of the enzyme treatment. The amount of extractives in ethanol:toluene also increased after the enzymatic treatment, and the dioxane-soluble kraft lignin underwent a noticeable decrease in its apparent molecular mass. This latter effect was readily attributed to the hydrolysis of aryl-ether bonds that survived the severity employed in the pulping process. These observations were useful to explain why LMS-recycled fibers produce handsheets with 9.4% better tensile strength than the control pulps.

The objective of this study was to evaluate the mechanical and optical properties of paper made from alkaline sulfite anthraquinone and methanol (ASAM) unbleached pulp from bamboo (Gigantochloa scortechinii). The bamboo pulps were beaten using a PFI mill at 10,000 revolutions. To determine the properties of unbleached bamboo ASAM paper, handsheets with a density of 60 g/m² were formed with 14 to 18% NaOH, 80/20 Na2SO3/ NaOH, 0.1% AQ, 0.5% EDTA, and 15% methanol pulping conditions. Pulping at 18% NaOH for 120 min cooking time produced paper with properties of 24.8 Nm/g and 43.02% for the tensile index and ISO brightness, respectively. Cooking at 16% sodium hydroxide for 90 min rendered the best results for mechanical and optical properties, with results of 20.86 Nm/g, 22.64 mN.m²/g, and 39.32% ISO value for the tensile, tear indices, and brightness, respectively. High quality bamboo paper produced by the ASAM pulping process was beneficial for producing highly durable paper and paperboard. [ABSTRACT FROM AUTHOR]

Two common Nigerian-grown biomasses, gmelina (Gmelina arborea) and bamboo (Bambusaa vulgaris) have been pulped and their fibre characteristics and paper properties examined. The results of their chemical compositions showed some fair similarities. The amount of glucose in the pulps of both biomasses indicated their suitability as lignocellulosic materials for pulping. Their pulp yield ranged between 48,0-54,1%, which fell within the acceptable range for good pulpwoods. The analysis of their fibre dimensions revealed that bamboo fibre has a wider fibre length distribution and higher fine length content. Gmelina and bamboo had weighted mean fibre lengths of 0,93 and 2,07 mm and mean fibre widths of 24,1 and 16,9 µm, respectively. The Runkel ratios of the samples were 0,4 (gmelina) and 0,9 (bamboo): this is indicative of their suitability for paper making. Mechanical properties of handsheets obtained from gmelina compared fairly well with South African pulpwoods (Eucalyptus grandis and Pinus paluta). Bamboo exhibited better tear index values than these woods but with lower sheet density and tensile index. These properties were significantly improved in handsheets obtained from blends of gmelina and bamboo, raising the prospect of producing paper from blends of both raw materials in Nigeria. [ABSTRACT FROM AUTHOR]

Antimicrobial cellulose fibers and paper products are of great importance for various applications. In this work, novel core–shell antimicrobial latexes based on hydrophobic acrylate monomers and antimicrobial macromonomer (GPHGH) were successfully prepared via a seeded semi-continuous emulsion copolymerization in the presence of a cationic surfactant. The surface properties as well as size of latex were tailored by varying the amount of GPHGH incorporated during the copolymerization. The resulting cationic nano-sized latexes showed the strong adsorption and formed monolayer on the surfaces of bleached sulfite fibers, thus rendering the cellulose fibers antimicrobial. An excellent antimicrobial activity (>99.99% inhibition) of modified fiber toward Escherichia coli was achieved at 0.3 wt% of latex dosage (on dry fibers). Results of transmission electron microscopy (TEM) observation confirmed that the particles obtained indeed possessed a desired core–shell structure. The latexes themselves exhibited high antimicrobial activities against E. coli with the minimum inhibitory concentration (MIC) as low as 6.25 ppm (similar to that of pure guanidine-based polymer). Moreover, the mechanical strength of the hand-sheets made from latex-modified cellulose fibers was also improved due to the filming of the latex on fiber surfaces. [ABSTRACT FROM AUTHOR]