Pulp and paper
Ramin Vaysi; Iesa Rezazadeh; S. ESHAGH EBADI
Abstract
Background and aim: Today, with the increase in population, increasing demand for paper, as well as greater restrictions on raw materials, the production of pulp from high-yield pulps and mechanical pulps has found a special place. These pulps have a high yield greater than 85%, but due to the presence ...
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Background and aim: Today, with the increase in population, increasing demand for paper, as well as greater restrictions on raw materials, the production of pulp from high-yield pulps and mechanical pulps has found a special place. These pulps have a high yield greater than 85%, but due to the presence of lignin, extracts, and metal ions, their use is limited to short-term usage, as in the long run they suffer from brightness reversion and photo-yellowing. This study aimed to investigate the effect of DTPA, nano-cellulose, and nano-chitosan spray on the optical properties of chemical-mechanical pulp (CMP). Materials and methods: For this purpose, first, a quantity of bleached chemical-mechanical pulp (CMP) was selected as a control sample from Mazandaran wood and paper industry. Papers with a base weight of 60 gr/m2 were prepared from the mentioned paper pulp. In this study, the nano-fibrillated cellulose (NFC) was purchased from Nano Novin Polymer Co. (Sari, Iran), which was prepared from softwood alpha cellulose pulp with an average fiber diameter of 32 nm. The NFC was loaded at 2% by spraying onto papersheets. Nanochitosan (“Seafresh”, Thailand), obtained from exoskeletons of crustaceans, with a deacetylation degree of 93% and a molecular weight of 270 kDa was used. Nanochitosan was loaded at 1 and 2% of the dry pulp weight. Diethylene triamine penta acetic acid (DTPA) was prepared from DIPER-Samchun (South Korea), with a 50% solid content and 25 cps viscosity. To spray the DTPA onto the paper surface, 0.5% DTPA was prepared. To prepare samples for the surface modification, paper sheets with a basis weight of 60 g/m2 were made. Then, 0.5% DTPA, 2% nanochitosan, and 2% nanocellulose were sprayed separately on the papersheets. In addition, another treatment named mixed-solution (containing 0.5 % DTPA + 2% nanochitosan + 2% nanocellulose) was sprayed onto the handsheets. The spraying time and distance were 20 s and 20 cm, respectively, and the treatment process was named “spray-coated”. Then, the optical properties (brightness, opacity, yellowness, and greenness) of the hand-sheets were measured according to ASTM and TAPPI standard methods. Results:The results showed that by DTPA, nano-cellulose, and nano-chitosan spray in the handsheet paper, brightness, yellowness, greenness, L* factor, and the opacity increased and the a* factor decreased. By spraying nano-cellulose on the test samples, most of the optical properties were significantly improved except for the yellowness of the hand-sheet paper. In addition, the most appropriate properties were observed in the paper obtained from DTPA spray and also in the simultaneous spray treatment of DTPA, nano-cellulose, and nano-chitosan on hand-sheet papers. Therefore, it has caused a very sensible increase and improvement in all the optical properties, which can be selected and suggested as the best treatment. The evaluation results of the brightness reversion of the hand-sheet paper from CMP pulp showed that most of the treatments led to a relative reduction of the return of the paper brightness. On the other hand, the lowest and highest brightness return values in the hand-sheet paper were obtained from 0.5% DTPA spray and nano-chitosan spray, respectively. The evaluation results of the SEM images of the test samples compared to the control sample showed that the hand-sheet paper with nano-chitosan and nano-cellulose spray and also in the simultaneous spray treatment of DTPA, nano-cellulose, and nano-chitosan had more favorable surface and structural properties. The existence of less empty spaces (cavity) and more overlap of fibers in the test samples can be a reason for the higher quality of the properties, as well.Conclusion:The results showed that by spraying nanocellulose, nano- chitosan and DTPA on the test samples, the optical properties, brightness, greenness, opacity, a* factor, l* factor , yellowness and brightness durability improved. In addition, among the various treatments, the DTPA treatment in long-term thermal aging and the use of nano-chitosan and nano-cellulose in the short-term aging had noticeable effects on brightness durability and decrease in the color reversion. As a result, there was an increase in the durability of the paper against thermal deterioration.
Eysa Rezazadeh; Ramin Vaysi; Mogtaba Soltani; Abdollah Najafi; S. ESHAGH EBADI
Abstract
This study was aimed to investigate the effect of polyalumium chloride and nano-chitosan on optical and mechanical properties of chemi-mechanical pulp. For this purpose, some of the bleached CMP pulp of Mazandaran Wood and Paper Industries (MWPI) were randomly selected as a control sample. In addition, ...
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This study was aimed to investigate the effect of polyalumium chloride and nano-chitosan on optical and mechanical properties of chemi-mechanical pulp. For this purpose, some of the bleached CMP pulp of Mazandaran Wood and Paper Industries (MWPI) were randomly selected as a control sample. In addition, the polyalumium chloride were used as a white powder at 4 levels of 0, 0.5, 1, and 1.5%. The nano-chitosan was then added to the CMP pulps suspensions at 3 levels of 0, 1, and 2%, as well. Hand-sheets with a basis weight of 60 gr/m2 were prepared from the mentioned pulps. The optical and mechanical properties were then measured and compared using TAPPI standard test methods. The results showed that by adding polyalumium chloride and nano- chitosan(separate) to the CMP pulps, brightness, opacity, greenness,tear, tensile, burst strengths, air resistance increased , but Cobb 60 and a* factor decreased. On the other hand, with the addition of nano-chitosan and polyalumium chloride to CMP pulp, the brightness and greenness increased, but tensile, burst, tear strengths, air resistance, Cobb 60 and opacity low decreased and then suitable increased. Moreover, the findings showed that by simultaneous adding 1% polyalumium chloride and 2% nano-chitosan(separate) and 2% nano-chitosan with 1.5% polyalumium chloride to the CMP pulp, most of the paper properties were improved. Therefore, it can also be introduced as the best treatment.
Ramin Vaysi; Yousef Yousefi-golordi
Abstract
This study was aimed to investigate the effect of cellulose nano-fibers and chitosan on optical and mechanical properties of chemi-mechanical pulp. For this purpose, some of the bleached CMP pulp of Mazandaran Wood and Paper Industries (MWPI) were randomly selected as a control sample. In addition, ...
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This study was aimed to investigate the effect of cellulose nano-fibers and chitosan on optical and mechanical properties of chemi-mechanical pulp. For this purpose, some of the bleached CMP pulp of Mazandaran Wood and Paper Industries (MWPI) were randomly selected as a control sample. In addition, the cellulose nanofibers were used as a white gel at 3 levels of 0, 2, and 3%. The chitosan was then added to the CMP pulps suspensions at 5 levels of 0, 0.5, 1, 1.5, 2%, as well. Hand-sheets with a basis weight of 60 gr/m2 were prepared from the mentioned pulps. The optical and mechanical properties were then measured and compared using TAPPI standard test methods. The results showed that by adding chitosan, tear, tensile, burst and breaking length strengths, air resistance, yellowness, and greenness increased and brightness, Cobb 60 and a* factor decreased. On the other hand, with the addition of chitosan and nano-cellulose to CMP pulp, the tensile, burst, breaking length strengths, air resistance, Cobb 60, yellowness and a* factor increased and the tear, brightness, and opacity decreased. Moreover, the findings showed that by simultaneous adding 2% chitosan, 2% chitosan, and 3% cellulose nanofibers to the CMP pulp, most of the paper properties were improved. Therefore, it can also be introduced as the best treatment.
Pulp and paper
Mojtaba Goli; Saeed Mahdavi
Abstract
Abstract In recent years, environmental problems of irregular wood harvesting and shortages of raw materials made wood and paper Ind. & country to be faced serious crises. And some researchers and industry experts have led to fundamental and long-term solution for supplying raw materials to these ...
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Abstract In recent years, environmental problems of irregular wood harvesting and shortages of raw materials made wood and paper Ind. & country to be faced serious crises. And some researchers and industry experts have led to fundamental and long-term solution for supplying raw materials to these industries. This present study aimed to determine the optimum conditions of pulping and bleaching for several hardwood forest species (as a separate cooking & Combining with 40% popular, 15% beech and hornbeam 45%) and paper evaluation. After preparing CMP in accordance with the terms of an 85% efficiency , Different cooking times (25-60 minutes, temperature of 170 °C, the ratio of L TO W & 7 TO 1 and Making hand sheet with standard 60 gram per square meter, Optical and mechanical properties of paper was evaluated. The results showed that, A species that was used in cooking, Poplar were better in terms of total properties with mechanical and optical properties. Also in Bleaching stage, the tensile strength index is decreased & Burst and tear strength index is improved. The maximum brightness is related to poplar species with mixing and without species and after bleaching the beech is the lowest ones. In both methods the rate of opacity and yellowness is decreased.
Pulp and paper
Ramin Veisi
Abstract
This research and aim was using Bamboo and Reed CMP pulp for newsprint production. For this purpose, some chips of bamboo stem in the west of Mazandaran were randomly chosen. Then CMP Pulps were prepared at the yield 85%in 120 minutes(Bamboo) and 31 minutes(Reed), by using cooking conditions of Wood ...
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This research and aim was using Bamboo and Reed CMP pulp for newsprint production. For this purpose, some chips of bamboo stem in the west of Mazandaran were randomly chosen. Then CMP Pulps were prepared at the yield 85%in 120 minutes(Bamboo) and 31 minutes(Reed), by using cooking conditions of Wood and Paper Industries of Mazandaran 60 gr/m2 newsprint handsheets were prepared from the Bamboo and Reed CMP and Mill(MWPI) CMP pulps, first in a separate and then mixed way with 25,50,75 percents. Then the optical and mechanical properties were measured and compared according by using TAPPI Standard test methods. The results showed that the most strength of the burst, breaking length, tensile, tear strength, yellowness and opacity were in the handsheets obtained from 100% the bamboo CMP pulp and the lowest strength (except brightness) was in Reed CMP pulp. The results also pointed out that the above-mentioned all strengths (except brightness) can be improved by using 25-100% of the bamboo CMP pulp, too. The results also indicated that 25-100% of the bamboo CMP pulp and 25% of the Reed CMP pulp can use for newsprint production.
Pulp and paper
Ali Solimani; Hossein Resalati; Eiman Akbarpoor
Abstract
In this research, effects of mixing the birch wood with hornbeam and beach on optical and physical properties of papers produced at constant freeness range of 300 ml, CSF and yield of 85% and reference of CMP pulp (75% hornbeam plus to 25% beach) was investigated. CMP pulp was produced from birch ...
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In this research, effects of mixing the birch wood with hornbeam and beach on optical and physical properties of papers produced at constant freeness range of 300 ml, CSF and yield of 85% and reference of CMP pulp (75% hornbeam plus to 25% beach) was investigated. CMP pulp was produced from birch chips at 10,20,30 and 40% content within the conditions of pulp yield:85%, liquor to dried chip ratio (L/W) of 7/1, sulfite percent of 20% on oven-dried wood chips, cooking temperature:1600C, cooking time:85-135 minutes blended with 60-90 % hornbeam and beach. After defibration and refining the cooked wood chips, the standard hand sheets of 60 g/m2 were made from different pulps and the optical and physical properties of paper produced were compared. The results from comparing the optical properties of paper showed that using up to 40% birch chips blended with hornbeam and beach led to brightness improvement and yellowness and opacity reduction compared to control CMP pulp. Increase of birch use to 30% indicated no significant effect on opacity values at confidence level of 99% compared to control CMP pulp. Utilizing 40% birch resulted in the preparation of papers with lower caliper, smoother surface and higher air resistance.
Pulp and paper
Mohammad Azadfallah; Arezo Noori
Abstract
Yellowing of lignin-rich mechanical pulp is mainly attributed to light-induced changes in lignin structure. Hence, in this study the photodegradation of milled wood lignin (MWL) prepared from hardwood bleached chemimechanical pulp (BCMP) was investigated. The lignin preparation was then impregnated on ...
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Yellowing of lignin-rich mechanical pulp is mainly attributed to light-induced changes in lignin structure. Hence, in this study the photodegradation of milled wood lignin (MWL) prepared from hardwood bleached chemimechanical pulp (BCMP) was investigated. The lignin preparation was then impregnated on Whatman filter paper and irradiated with UV light during 4 hour exposure time. Then, photodegraded lignin was recovered and characterized by 13C-NMR.Irradiation caused to β-O-4 bonds cleavage, increase in carboxylic and phenolic hydroxyl groups, decrease in methoxyl, primary and secondary hydroxyl group. The amount of β-β and β-5 condensation structures was increased during irradiation.
