Pulp and paper
fatemeh rajabi; seyed majid zabizadeh
Abstract
The objective of this study was the evaluation of optical, mechanical properties of chemi-mechanical pulp which were bleached by one and two stage bleaching sequence of hydrogen peroxide and sodium hypochlorite. Also the environmental effects of effluents from bleached paper liquor were studied. For ...
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The objective of this study was the evaluation of optical, mechanical properties of chemi-mechanical pulp which were bleached by one and two stage bleaching sequence of hydrogen peroxide and sodium hypochlorite. Also the environmental effects of effluents from bleached paper liquor were studied. For this purpose, unbleached CMP pulp mixed of hardwoods was prepared from Mazandaran Wood and Paper mill. Then, these pulps were bleached using P (hydrogen peroxide), H (Sodium Hypochlorite), PH (Hydrogen Peroxide and Sodium Hypochlorite) and HP (Sodium Hypochlorite and hydrogen peroxide) stages. 60 gr/m2 hand sheets were prepared and the optical, mechanical properties of hand sheets and also their effluent bleaching liquor characteristics were measured and analyzed based on TAPPI and APHA Standards. The results showed that when peroxide was applied at the last stage of bleaching, then the properties such as tear, tensile and brightness have increased and yellowness has decreased. Generally, the role of single sequence of bleaching by P and two sequence of bleaching with HP were more effective than single sequence of H or unbleached pulp. Based on results, the highest and lowest COD load is related to bleaching liquor of H and PH respectively. Moreover, bleaching liquor of hydrogen peroxide had the highest BOD load and the lowest amount of BOD is related to PH sequence of bleaching.
Pulp and paper
Hamid reza Rodi; Hasibeh Saeidi
Abstract
Current study was done with the aim of investigating the effect of polymeric multilayers of cationic starch and anionic starch upon CMP fibers using layer-by-layer technique on its pulp and paper properties. Consecutive cationic and anionic starches layering experiments (respectively 1% and 0.5% dose ...
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Current study was done with the aim of investigating the effect of polymeric multilayers of cationic starch and anionic starch upon CMP fibers using layer-by-layer technique on its pulp and paper properties. Consecutive cationic and anionic starches layering experiments (respectively 1% and 0.5% dose of each starch based on oven-dry fibers) with layering time of about 10 minutes were conducted to assemble one to five successive ionic starches onto CMP fibers. Pulp properties including: freeness, water retention value and zeta potential were examined. Then, handsheets with basis weight of about 60 g/m2 were prepared and their properties were analyzed. Succeeding variation of zeta potential designated formation of successive layers of starches onto the CMP fibers. Furthermore, pulp freeness and water retention value has been enlarged by increasing the number of formed layers. The results of paper properties analysis showed that bonding-ability of fibers including tensile index and burst index have been considerably improved. The prepared SEM micrographs indicated of making more bonds between fibers due to the higher absorption of cationic starch.
Ramin Veysi
Abstract
In this research, chips of kiwi residues from western Mazandaran (Tonkabon region) were randomly chosen and its kraft pulp was prepared with yield of 53% for 105 minutes. The kraft liner handsheets were prepared from both kiwi and Chooka Mill kraft pulps (control sample), first in a separate and second, ...
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In this research, chips of kiwi residues from western Mazandaran (Tonkabon region) were randomly chosen and its kraft pulp was prepared with yield of 53% for 105 minutes. The kraft liner handsheets were prepared from both kiwi and Chooka Mill kraft pulps (control sample), first in a separate and second, in mixed way. Then, their optical and mechanical properties were compared according to TAPPI standard test methods. Results showed that the highest tear strength and cobb 60 and the lowest breaking length, burst and CMT values were in the handsheets obtained from pure kiwi kraft pulp. The handsheets’ properties increased in the samples prepared from mixed pulps. In general, the highest values of breaking length, burst strength, tear strength, cobb 60, brightness and RCT were observed in the handsheets prepared from mixed 10-30% kiwi kraft pulp and mill kraft pulp. The results also pointed out that the above mentioned strengths could be improved by adding 10-30% of kiwi kraft pulp to 30-70% mill kraft pulp replaces part of mill kraft pulp, but it is not possible for pure kiwi kraft pulp.
Porya Rezaei niaraki; Ahmad Jahan Latibari; Azhang Tajadini; Mehran Roohnia
Abstract
The influence of fiber lignin content and the dosage of coupling agent on the strength and physical properties of cellulosic fiber-polypropylene composite were investigated. The old corrugated container (OCC) fibers were delignified using sodium hydroxide to reach the lignin content of 2.7, 3.78, 5.26 ...
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The influence of fiber lignin content and the dosage of coupling agent on the strength and physical properties of cellulosic fiber-polypropylene composite were investigated. The old corrugated container (OCC) fibers were delignified using sodium hydroxide to reach the lignin content of 2.7, 3.78, 5.26 and 7%. Fibers were compounded with polypropylene by extrusion process using 20% fibers and 77% PP and the extrudate was cooled and grinded to fine granulates before injection molding. MAPP coupling agent was applied at three different levels (1, 2 and 3 percent based on the total weight of the composite). The strength properties of the composites were measured using relevant ASTM test methods and the results were statistically analyzed using factorial experiment under complete randomized design. The impact of fiber lignin content of flexural strength of composite was statistically significant at 98 percent significance level and the lowest and highest values of flexural strength of composite were measured at 3.78 percent and 7 percent lignin content of fiber. The interactive effect of fiber lignin and MAPP on the tensile strength and flexural modulus of elasticity of the composite showed that at lower values of lignin and higher dosage of MAPP, these properties are 38.7 and 3438 MPa respectively. Other strength values of the composites were also improved and at lower content of lignin and increaing dosages of the MAPP, the impact strength of the composites was increased from 52.82 J/m to 60.26 J/m.
ُSima Sepahvand; Meysam Zahedi; Samaneh vilki; Taghi Tabarsa
Abstract
Tannins are the most desirable natural, renewable phenolic components which obtained from plant resources. The phenolic nature of tannins causes that this materials react with formaldehyde and form tannin-formaldehyde resins. In this study, the raw materials of wheat straw and forest woods were used ...
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Tannins are the most desirable natural, renewable phenolic components which obtained from plant resources. The phenolic nature of tannins causes that this materials react with formaldehyde and form tannin-formaldehyde resins. In this study, the raw materials of wheat straw and forest woods were used for producing of particleboard (with a ratio of about 50 to 50 percent) using phenol formaldehyde based on tannin. Tannin as a powder was added at 10 and 20 percent (based on dry weight of resin solution) to formalin 35% for glue making. Particleboards were made at two range of thickness, 10 and 16 mm and their properties of including bending strength, modulus of elasticity, internal bonding, thickness swelling and water absorption were measured. The results from this investigation showed that the strength properties of the made boards from combined wood chips were lower than those from pure wood chips. Also, increasing of tannin usage into phenol formaldehyde caused to increase internal bonding or adhesion, swelling and water absorption (2 and 24 hours) of the boards.
Mahid Farzi; Ali akbar Enayati; Davood Parsa paghoh
Abstract
In this investigation, soda pulps from old rags applying three pulping times (60, 120 and 180 minutes ) and three levels of active alkali ( 6,8, and 10% NaOH based on OD weight of rag) and pulping temperature of 125º C were produced. Liquor to rag ratio was kept constant at 11:1(based on the ...
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In this investigation, soda pulps from old rags applying three pulping times (60, 120 and 180 minutes ) and three levels of active alkali ( 6,8, and 10% NaOH based on OD weight of rag) and pulping temperature of 125º C were produced. Liquor to rag ratio was kept constant at 11:1(based on the weight of the rag). After pulping, hand sheets were made and then both strength and optical properties of hand sheets were measured. It was revealed that, the optimum condition for rag pulping was; 8% active alkali and 120 minutes. At this pulping conditions, the pulping yield and mechanical and optical properties of pulp were measured as yield; 86.46 %, tear index; 20.12 mN.m2/g, burst index; 2.09 kPa.m2/g, breaking length; 1.96 km, brightness; 95.86 % and opacity: 96.39
Sabah Ashrafi birghani; Ahmadreza Sraeyan
Abstract
The purpose of this study was to compare the effects of various concentrations of sodium hydroxide and treatment times on the properties of bagasse and Eastern cottonwood (Populus deltoids) cold soda pulp and paper. The cold soda pulp was prepared using various concentrations of sodium hydroxide (5, ...
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The purpose of this study was to compare the effects of various concentrations of sodium hydroxide and treatment times on the properties of bagasse and Eastern cottonwood (Populus deltoids) cold soda pulp and paper. The cold soda pulp was prepared using various concentrations of sodium hydroxide (5, 10, 15% based on oven dry weight), different treatment times (20, 40, 60 min.), and constant liquor to wood ratio of 10:1 at 25 ºC and atmospheric pressure. The pulp prepared after 40 min treatment time was selected and refined to the freeness of 400 ml CSF. Analysis of the properties of hand sheets was conducted based on completely randomized design. Duncan multiple range grouping test was used to classify the properties of papers. The results indicated that, the yield of pulp obtained from Eastern cottonwoodand bagasse pulp varied between 86.54% to 94.52% and 70.65 to 87.32% respectively. The absorbed alkali was varied from 2.15% to 4.78 % for Eastern cottonwood and 3.06% to 6.80% for bagasse. Eastern cottonwood had the highest yield, thickness and strength properties whereas the highest absorbed alkali and paper density were observed in bagasse. It was observed that as the concentration of sodium hydroxide was increased from 5% to 15%, the yield of pulp and the thickness of paper decreased, while the absorbed alkali, density and the strength properties of paper increased. In general, the cold soda pulp from Eastern cottonwood provided higher quality compared with bagasse under the same pulping conditions.
Pulp and paper
Maryam Rostaei; Rabi Behroz; Saeid Mahdavi
Abstract
This research was performed to improve the properties of the pulp made of Aspen Deltoides, using antraquinone(AQ) catalizer. Neutral sulfite semichemical (NSSC) method in three efficiency levels of 55, 60, and 65% was applied. Cooking situations was selected as: Specific Temperature (175˚ C) , Time ...
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This research was performed to improve the properties of the pulp made of Aspen Deltoides, using antraquinone(AQ) catalizer. Neutral sulfite semichemical (NSSC) method in three efficiency levels of 55, 60, and 65% was applied. Cooking situations was selected as: Specific Temperature (175˚ C) , Time (Variable) , Specific Percentage of Chemicals 14% and Anthraquinone 0.1% . In all stages of cooking, weight ratio of sodium sulfide to sodium bicarbonate was set as 4.5/1. The ratio of cooking liquid to chips was 5/1. The results indicated that AQ causes an increase in efficiency and a significant decrease in Kappa. Researches also indicated that by the use of AQ, strength indexes of the paper such as strength of burst, tearing, tensile, Ring Crush Test and Corrugating Medium Test increases. Optical experiments on hand sheets following addition of AQ, indicated increase in brightness and decrease in opacity.
Pulp and paper
Saeid Kamrani; Ahmad reza Saraeyan; Eyman Akbarpoor
Abstract
In this study, mechanical and optical properties of CMP, one stage APMP and two stage APMP pulps ( from Tajan wheat straw Golestan province ) were investigated. wheat straw collected at research center of Agriculture and Natural resources of Golestan province. Fiber dimensions such as average fiber length ...
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In this study, mechanical and optical properties of CMP, one stage APMP and two stage APMP pulps ( from Tajan wheat straw Golestan province ) were investigated. wheat straw collected at research center of Agriculture and Natural resources of Golestan province. Fiber dimensions such as average fiber length , diameter cell , lumen and fiber wall thickness were assessed at 1.18mm, 18.156, 11.461 and 3.396 microns, respectively. chemical components such as cellulose , lignin , ash and extractives were assessed at 53.7, 21.1, 5.1 and 8.5 percent, respectively. Based on the preliminary experiment results, impregnation temperature was 950C, impregnation times of 10, 20, 30, 40 minutes, caustic charge 10% and peroxide charge was 3% in CMP ,one stage APMP and two stages APMP pulps. Considering pulp properties and treatment conditions, many treatments including 20 and 40 minutes treatments were selected for making of handsheet. The selected pulps were refined up to 350 ml (CSF) freeness prior to making of hasndsheet. Final results indicated that two stages APMP pulp (impregnation in time 40 minutes) had the highest burst strength, breaking length and brightness. Also, the results of yield and tear strength showed that, there was no meaningful difference at the 5% level between three methods CMP, one and two stages of APMP pulps.
