Pulp and paper
somayeh heydari; Ahmad Reza Saraeyan; Mohamadreza Dehghani firozabadi; Alireza Shakeri; babak shokri
Abstract
Ethylene vinyl alcohol (EVOH) copolymer is of semi crystalline materials with excellent barrier properties to gases. Also, it has shown outstanding chemical resistance. Despite its low gas permeability, EVOH copolymer displays poor water and water vapor resistance. In this study, Trimethoxymethylsilane ...
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Ethylene vinyl alcohol (EVOH) copolymer is of semi crystalline materials with excellent barrier properties to gases. Also, it has shown outstanding chemical resistance. Despite its low gas permeability, EVOH copolymer displays poor water and water vapor resistance. In this study, Trimethoxymethylsilane (as hydrophobic coating) was deposited by Plasma Enhanced Chemical Vapor (PECVD) method on the coated paper with Ethylene vinyl alcohol in order to improve the paper's barrier properties of moisture transmission. Coating by PECVD method was done in the certain conditions of time 6 min and pressure 300 m Torr. Different treatments were applied for power including 50, 70 and 90W.Then contact angle was measured in order to determined improvement of the paper's barrier properties of moisture transmission . The result showed that papers which were coated with Trimethoxymethylsilane had higher contact angle water 55.7% more than the control. The results revealed that the best condition was obtained by 50 W power. The structural and chemical properties of deposited layer were observed with Fourier Transform infrared spectroscopy- Attenuated Total Reflectance (FTIR-ATR) and Energy Dispersive X-ray Spectroscopy (EDS). The results confirmed bonding of silane on the surface EVOH polymer.
Pulp and paper
Mohsen Mohammadi Achachlouei; Fahimeh Yousefi
Abstract
Paper is a dominant tool that is traditionally used for recording human knowledge and cultural heritage. Paper as organic material is at risk of biodegradation processes by various microorganisms including fungi, which cause irreversible degradation, color modification and instability of the historical ...
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Paper is a dominant tool that is traditionally used for recording human knowledge and cultural heritage. Paper as organic material is at risk of biodegradation processes by various microorganisms including fungi, which cause irreversible degradation, color modification and instability of the historical papers. Thus, the utilization of appropriate conservation methods and restoration treatments to minimize the adverse effects of fungi on historical papers have received great attention. Recently, Benomyl as an antifungal revealed a significant inhibitory effect on the fungal growth on the historical papers. In this study, the effect of Benomyl on gall ink as a popular and important ink used in cultural heritage was investigated. In a first step of the evaluation, the gall ink was prepared based on the historical recipes and then was implemented on surface on filter paper. The prepared samples were dipped into 100 ppm Benomyl-ethanol solution and aged after drying. The effect of Benomyl on gall ink was evaluated by the pH values of aqueous extracts, CIE Colorimetry, paper strengths, FTIR-ATR spectroscopy and SEM microscopy. Results indicated that the Benomyl in concentration of 100 ppm had no adverse effect on the gall ink and paper surface. However, dipping of paper in the Benomyl-ethanol solution resulted in a significant loss of paper strengths. In order to overcome this problem, it would be necessary to use a suitable solvent or another technique such as spraying for surface application of Benomyl.
Pulp and paper
Hossein Jalali Torshizi; Abdollah Aabedi Bafraajerd; Reza Shidpour
Abstract
DOR:98.1000/1735-0913.1398.34.1.66.1.1578.32 Providing some paradox properties of paper products at the same is of utmost challenging issues of papermakers, e.g., attaining proper strength together with high water absorbency in hygienic papers. Because higher bonding resulted in lesser accessibility ...
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DOR:98.1000/1735-0913.1398.34.1.66.1.1578.32 Providing some paradox properties of paper products at the same is of utmost challenging issues of papermakers, e.g., attaining proper strength together with high water absorbency in hygienic papers. Because higher bonding resulted in lesser accessibility to the hydrophilic functional group. Therefore, hydrogel as an ever-increasing material in bulk cellulosic diapers were surficial coated on paper and compared with distillated water saturated papers. The prepared chitosan-acrylic acid (AA) hydrogel converted into nanoparticles by ultrasonic homogenizer and the nano scaled particles approved by Dynamic Light scattering (DLS). SEM images and paper caliper revealed the nanohydrogel coating layer. All papers water uptake coated with 1, 1.5 and 2% nanohydrogel increased significantly up to 50% compared to the untreated sample. Burst and dry tensile strengths along with water uptake improved, with no toleration in tear strength. Increased fiber bonding due to plenty of carboxylic acid in AA together with hydroxyl and amine groups in chitosan, along with nanohydrogel film formation as a complementary assembly and constituent with the cellulosic substrate of paper were resulted in strength improvement. Wet tensile strength of paper revealed remarkable increment at 2% coating application, only; without enhancing effects at the lower dosages. Paper opacity, brightness and whiteness stayed almost stable, but due to chitosan yellowish nature, the paper yellowness increased. The coated paper stiffness enhanced compared to untreated paper, but revealed lesser stiffness than water saturated papers. Water treated papers revealed caliper, tensile and burst indices reduction and stiffness rising.
Pulp and paper
Bardia Sodeifi; noureddin Nazarnezhad; Seyed Hassan Sharifi
Abstract
DOR:98.1000/1735-0913.1398.34.45.66.1.1576.1610 In this research, the effect of coating with Polycaprolactone (PCL), nanocrystalline Cellulose (NCC) and zinc oxide Nanoparticle (ZnO NP) and their blend were investigated on the mechanical and optical properties. First, coating materials with specific ...
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DOR:98.1000/1735-0913.1398.34.45.66.1.1576.1610 In this research, the effect of coating with Polycaprolactone (PCL), nanocrystalline Cellulose (NCC) and zinc oxide Nanoparticle (ZnO NP) and their blend were investigated on the mechanical and optical properties. First, coating materials with specific condition (PCL 10%, NCC 4 and 6%, ZnO 3%) were coated on the papers. The coating materials weight on the papers was (2.2- 2.7 g/m2). The results showed that the mechanical properties (Tensile strength index, Burst strength index and Tear strength index) of the coated papers were enhanced with addition of NCC. The ternary blend of these coating materials had the best mechanical properties than the neat paper. With addition of NCC the brightness were enhanced and the opacity were reduced. Also, the color properties were improved with addition of NCC and ZnO and the effect of ZnO was more remarkable than NCC but, in ternary blend of materials, the color properties were improved with increasing the amount of NCC.
Pulp and paper
Mohaddeseh Ramezanpour-Charvadeh; Hamid reza Rodi; Hossein Jalali-Torshizi; Hamidreza Ghomi marzdashti
Abstract
DOR:98.1000/1735-0913.1398.34.76.66.1.9.1578 A need for control of pathogenic microorganisms in contaminated environments has motivated to prepare the products including antibacterial papers resisting against growth of such creatures. Different methods and materials have been used to make these papers. ...
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DOR:98.1000/1735-0913.1398.34.76.66.1.9.1578 A need for control of pathogenic microorganisms in contaminated environments has motivated to prepare the products including antibacterial papers resisting against growth of such creatures. Different methods and materials have been used to make these papers. The purpose of current research is to fabricate silver nanoparticle by means of plasma method and investigate the effect of adding it to the Kraft pulp on the properties of resulting papers. To do this, silver nanoparticles have been fabricated in optimized conditions of 1 kHz frequency, 2 A current and 4 kV voltage, using an instrument developed in Laser and Plasma Research Institute, Shahid Beheshti University. The DLS test confirmed the average size of silver particles at nano scale ( 41.2 nm). Then, the prepared silver nanoparticles were added by levels of 0, 25, 50 and 75 ppm to the Kraft pulp accompanying by cationic polyacrylamide (CPAM) as a retention aid to about 0.05 based on oven dry of fibers. The results of paper properties evaluation (having basis weight 60±3 g/m2) have shown that addition of silver nanoparticles synthesized by plasma method lead to loss of paper strength characteristics. The paper brightness has also exhibited a meaningful decrease. However, the paper opacity and antibacterial property develop significantly in the consumption levels higher than 50 ppm.
Pulp and paper
somayeh heydari; Ahmad Reza Saraeyan; Mohammad Reza Dehghani Firouzabadi; Alireza Shakeri; babak shokri
Abstract
DOR:98.1000/1735-0913.1398.34.100.66.1.9.1604 In this study, EVOH was coated on paper made of CMP pulp by extrusion method in order to improve the paper's barrier properties of oxygen transmission. Ethylene vinyl alcohol (EVOH) shows poor moisture resistance despite less gas permeability. Then, dimethoxydimethylsilane ...
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DOR:98.1000/1735-0913.1398.34.100.66.1.9.1604 In this study, EVOH was coated on paper made of CMP pulp by extrusion method in order to improve the paper's barrier properties of oxygen transmission. Ethylene vinyl alcohol (EVOH) shows poor moisture resistance despite less gas permeability. Then, dimethoxydimethylsilane was deposited using Plasma Enhanced Chemical Vapor Deposition on EVOH film as the hydrophobic layer. A random factorial experiment was designed with three factors at three levels including time (6-8-10 min), pressure (30-0400-500 m Torr), and radio frequency power (50-70-90 W). The contact angle, oxygen transmission rate, tensile strength, and strain energy were measured to obtain the optimum condition. Expert Design method using response surface was used to optimize the condition coating Dimethoxydimethylsilane in order to improve the hydrophobic properties, reduce OTR, increase tensile strength and strain energy. Based on this method the optimum condition was suggested as: time 6 min, pressure 499.99 m Torr and power 50W. Keywords: Extrusion , Contact angle, Oxygen transmission rate, Response Surface methodology.
Pulp and paper
Zohreh Taheri; Hamidreza Rodi; Hossein Jalali-Torshizi; Reza Shidpour
Abstract
DOR:98.1000/1735-0913.1398.34.112.66.1.1578.1610 Nowadays, the barrier property against water take up of different packaging papers which mostly prepared from recycled fibers is of highly significance for paper manufacturers. In current study, the effect of AKD sizing agent has been examined on the properties ...
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DOR:98.1000/1735-0913.1398.34.112.66.1.1578.1610 Nowadays, the barrier property against water take up of different packaging papers which mostly prepared from recycled fibers is of highly significance for paper manufacturers. In current study, the effect of AKD sizing agent has been examined on the properties of papers made from recycled fibers of Atrak pulp and paper industries. Sizing of pulp suspension using AKD was conducted at levels of 0, 0.5, 1 and 1.5 % based on oven dry (OD) pulp in neutral pH (7), according to the TAPPI standard methods. Then, by preparation of handsheets with basis weight of about 60±3 g/m2, their Cobb test (60 second) and different characteristics were evaluated. According to the statistical analysis of the results, up to 1 % AKD consumption amount based on OD pulp exhibited for optimum level in internal sizing of these recycled fibers. In such AKD level, water take up of size-free papers revealed 174±7.4 g/m2, decreased to the value of about 24±1.7 g/m2 in AKD-treated papers. Further, contact angle of water droplet with the paper surface increased from 35.2º to 109.1º. Applying 1 % of AKD, paper tensile index increased to 33.2±1.01 N.m/g by 2.4 unit compared to the base paper. Apparently, such phenomena can be attributed to the AKD potential in creating hydrogen bonds which concurrent to the development of paper water repellency, resulted in improving bonding-ability of paper network. Additionally, AKD treatment led to in meaningful increase of paper opacity. This can also be attributed to the increase in filler retention in fibers network, which influences the development of light scattering from the paper surface.
Pulp and paper
ghasem asadpour; fatemeh rajabi; seyed majid zabizadeh
Abstract
High yield and chemi-Mechanical pulps are susceptible to oxidation-optical and thermal reactions. These reactions result discoloration and brightness reversion in pulps. In this research, chemi-mechanical pulps were selected randomly from Mazandaran pulp and paper mill and were bleached separately by ...
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High yield and chemi-Mechanical pulps are susceptible to oxidation-optical and thermal reactions. These reactions result discoloration and brightness reversion in pulps. In this research, chemi-mechanical pulps were selected randomly from Mazandaran pulp and paper mill and were bleached separately by P, H, PH and HP sequences and sheets with 60 gr/m2 gramage were prepared from these bleached pulps. All the prepared papers went through thermal aging, separately at 0, 12, 24, 36 and 48 hours at 1050C in oven, and their optical properties, including, their brightness, their a, b and L factor, α exponent, yellowness, opacity, K/S ratio, and PC number before and after thermal aging were measured and compared based on TAPPI standard. The results of this study showed that, during thermal aging from 0 to 48 h, paper optical properties such as brightness, L and a factor were decreased and b factor, yellowness, α, K/S ration and PC number were increased. As a result, bleaching by P and HP sequences had the highest amount of brightness and L factor and lowest amount of a and b factor, α exponent, yellowness, K/S ratio and PC number. Therefore, these bleaching sequences had important influences on brightness stability and decrease in paper brightness reversion and increasing their durability against thermal degradation.
Pulp and paper
Seyed Hassan Sharifi; nouredin Nazarnezhad
Abstract
To reuse recycled cellulosic fibers in paper production, contaminated particles and other impurities of the fibers can be greatly removed using a de-inking stage which is considered as a supplementary step in waste paper recycling technology. The effect of using ultrasonic pretreatment on the deinking ...
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To reuse recycled cellulosic fibers in paper production, contaminated particles and other impurities of the fibers can be greatly removed using a de-inking stage which is considered as a supplementary step in waste paper recycling technology. The effect of using ultrasonic pretreatment on the deinking of old newspapers was investigated utilizing the common conventional chemical method across this research work. Experimental design method was served to optimize the amount of ultrasonic bath temperature and sonication time. Therefore, 13 tests were designed using Response Surface Methodology (RSM) and Central Composite Design with Design Expert 7.0.0 Trial software. Ultrasonic bath temperature and sonication time at three different levels (1, 0 and 1+) and two axial points (α + and α-) were used as independent variables, and the optical and mechanical properties of handsheets were used as dependent variables. Response surfaces and contour plots were served to show the interaction between the independent variables and the response variable. ANOVA test showed that the quadratic model is the best model to explain the interaction among the studied variables. The predicted values of the obtained model had much conformity with the experimental results (R2=0.98). According to ANOVA results, it can be concluded that the effect of each of the variables on the optimal properties is significant and the ultrasonic time is the most effective factor on the response. According to the results, the proposed optimum conditions to achieve the highest amount of mechanical and optical properties (43.43) are the ultrasonic bath temperature 47 oC and the ultrasonic time of 31 min.
Pulp and paper
Pejman Rezayati Charani; Ahmad Azizi. Mossello
Abstract
The use of old corrugated container (OCC) is considered an effective solution by the paper industries in paper and paperboard productions bearing environmental and economic reasons. The strength properties of pulp made from recycled paper is weaker than the original pulp for various reasons, such as ...
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The use of old corrugated container (OCC) is considered an effective solution by the paper industries in paper and paperboard productions bearing environmental and economic reasons. The strength properties of pulp made from recycled paper is weaker than the original pulp for various reasons, such as hornification. Therefore, various methods as adding strength enhancing materials and mechanical treatments are used to improve the quality of them. Because of little amount of production, many of the paper recyclers have limitation in investment of using mechanical treatments (refiners) in their production line. In this research, using cationic starch and cellulose nanofibers(CNF) was investigated as strengthen additives and as an alternative for mechanical refining in the paper and paperboard production from OCC. In this study, cationic starch in one level (2%) and cellulose nanofibers in 3 levels (2, 4, 6%) were used and compared to control (refined and non-refined) samples. Results showed that 2% CS and 4% CNF improved the tensile and burst indices same as or more than refining of pulp, while the pulp dewatering time and paper density were equal. Therefore, the aforementioned conditions are recommended as a substitute for refining in small units of waste paper recycling for paper and paperboard production.
Pulp and paper
mohammad bashir torabian; behzad baziyar; mohammad talaeipour
Abstract
Abstract This research investigates the cooking of monoethanolamine with a concentration of 50% and baking alkali sulphite with 18% alkalinity for making pulp from corn stalks. The combination of sodium hydroxide and sodium sulphite in rations of 70:30 as a measure of alkali sulphite and water and monoethanolamine ...
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Abstract This research investigates the cooking of monoethanolamine with a concentration of 50% and baking alkali sulphite with 18% alkalinity for making pulp from corn stalks. The combination of sodium hydroxide and sodium sulphite in rations of 70:30 as a measure of alkali sulphite and water and monoethanolamine with a ratio of 50:50 were selected as control treatments. The amount of deficiency was eliminated during all three processes due to the fact that it was not very minor and could not be weighed. Furthermore, the cooking conditions were chosen as variables: the process of alkali and soda sulphite was combined; time was 30:60:90 minutes at the three levels and the temperature was 125.145.165 degrees at the three levels; and the ratio of the baking fluid to the raw material (1 to 4) remained constant. The paper pulp produced with monovalent and 50% had the lowest amount of total efficiency (36.12) and kappa number (17.93). In alkaline sulphite treatment, it was observed that decreasing the temperature and increasing the time as variable factors, results in a decrease in the total return value and the kappa number likewise increases, so that the highest burst index (6.78) is related to baking with a temperature of 125 degrees and the total time would be 60 minutes. The results of this study show that monoethanolamine/water (50:50) can be successfully used to make paper from corn stalks, and the characteristics of the pulp of manufactured paper, especially in terms of mechanical strength and kappa number, when mixed with water; and that it is superior to the process of alkali sulphite both as a combination and by itself
Pulp and paper
Ali Safizadeh; Hossein Jalali tarshizy; Hamidreza Rudi; Ali Partovinia
Abstract
Recycling necessity of different paper and board grades is clear from various points of view which is accompanied with huge value addition, especially in writing and printing papers. Mineral filler applicability and its more usage in papermaking are increasingly focused and for recycled pulp, include ...
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Recycling necessity of different paper and board grades is clear from various points of view which is accompanied with huge value addition, especially in writing and printing papers. Mineral filler applicability and its more usage in papermaking are increasingly focused and for recycled pulp, include binary advantages, which have recently researched. The characteristics of recycled fiber and interest in fillers, made the application of dry strength additives inevitable that natural and economical adhesives for this purpose are always seeking. In these regards, effects of precipitated calcium carbonate (PCC) and Soy Protein (SP) on recycled pulp from writing and printing waste papers were investigated. SEM micrographs proved PCC retention which is compatible with the paper Ash results, but ash percentage declined by filler more addition. SP improved initially filler retention originated from the recycled pulp and also the PCC retention. Preservation of the initially filler caused higher total retention in the presence of SP and the same effect is reportable in simultaneously utilization of PCC and SP compared to the SP absence. So, the recycled pulp total retention decreased meaningful in lack of SP. Polymeric and various functional groups in the SP biopolymer could be attributed for these results. SP employment improved freeness (CSF) of the recycled pulp up to 8% and was observed in the highest premixing of SP/PCC (15%). Replacing of recycled fibers by PCC also improved freeness, meaningful. The freeness results were proved by drainage time of the pulp in handsheet maker. PCC application in the all studied levels (10, 12, 15%) and its premixing by SP reduced the paper water absorbency, unmeaningful. However, the paper tensile index declined by PCC and SP consumption.
Pulp and paper
Moghadaseh Akbari; Hossein Resalati; Ahmad reza Saraeyan; Mohammad reza Dehghani Firoz Abadi
Abstract
During the paper manufacturing process, especially when mechanical pulp or recycled pulp used, a large amount of soluble and colloidal substances (DCS) are comprised and dispersed or dissolved in the process water. Accumulation of DCS during the papermaking operation with the increasing closure process ...
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During the paper manufacturing process, especially when mechanical pulp or recycled pulp used, a large amount of soluble and colloidal substances (DCS) are comprised and dispersed or dissolved in the process water. Accumulation of DCS during the papermaking operation with the increasing closure process water systems, can have a variety of deleterious effects on papermaking process and paper products. In this study, The effect of anionic trash neutraliziation was investigated by using different catcher anionic tarsh and also pulp washing (removal of anionic trash) on the CMP pulp and paper properties. After the initial preparation chemi-mechanical pulp (CMP), bleached long fiber kraft pulp and mixing the pulps with each other, filler of precipitated calcium carbonate (PCC) was added. Then a cationic retention aid That in this research has been cationic polyacrylamide were added to the mix. To neutralization of and reduce the negative effects of anionic trash, different levels of poly DADMAC with molecular weight 100000-200000 (0.025, 0.05, 0.1, 0.15%) and poly aluminium chloride (PAC) (0.1, 0.25, 0.5%) was added before adding of retention aid. Results showed that the use of different neutralizers imprived of zeta potential and drainage time of pulp, and increase of total retention; but reduces burst index of paper that was not significant statistically. CMP pulp washing and drainage treatment caused reducing COD and on the other hand reduced the amount of anionic trash with organic origin. Washing treatment pulp improved drainage time from pulp, total retention; but reduced burst index. Based on these findings, using cationic polyelectrolyte can introduce as a good strategy to reduce the harmful effects anionic trash and more retention suspension components.
Pulp and paper
Yaghob Mamizadeh; Jafar Ebrahimpour Kasmani
Abstract
In textile industry the bellow comb fibers are located in a range in terms of their length and diameter that it can be used as proper raw material especially in paper dough industries; therefore, present study tries to consider improvement of durable paper's properties made of cellulosic nanofibers. ...
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In textile industry the bellow comb fibers are located in a range in terms of their length and diameter that it can be used as proper raw material especially in paper dough industries; therefore, present study tries to consider improvement of durable paper's properties made of cellulosic nanofibers. In this consideration, the below comb fiber of pulp and paper imported chemical pulp are prepared from a company that is producing durable papers and they were transferred to laboratory. Cellulosic nanofiber has been prepared from Nano Novin Polymer Co., and it has been consumed at 4 levels of 0, 0.3, 0.6 and 0.6%. After mixing pulp with cellulosic nanofiber at determined percentages, the handmade 90 g.m-1 papers were made and eventually physical and mechanical properties of these papers were evaluated. The results showed that enhancement of cellulosic nanofibers till 0.9% has led to enhancement of tensile strength, bursting resistance, tearing strength and folding strength comparing to control sample up to 22.7, 38.9, 7.7 and 384% respectively. Increasing the amount of cellulosic nanofibers up to 0.9% the surface smoothness has increased up to 7.9% comparing to control; moreover, water absorption and pores were reduced as 69 and 7.9% respectively. The SEM results showed that enhancement of cellulosic nanofiber percentage has led to reduction of pores.
Pulp and paper
Abdolrahim Mohebalian; Ahmad Jahan latibari; Ajang Tajdini; Shadman Pourmosa
Abstract
In this research, the influence of two temperatures (60 and 90°C) and three dosages of sodium hydroxide (5, 7.5 and 10%, based on the dry weight) on hornbeam wood chips alkaline pre-hydrolysis and soda pulping was studied. Soda pulping of both pre-hydrolyzed and control chips were conducted applying ...
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In this research, the influence of two temperatures (60 and 90°C) and three dosages of sodium hydroxide (5, 7.5 and 10%, based on the dry weight) on hornbeam wood chips alkaline pre-hydrolysis and soda pulping was studied. Soda pulping of both pre-hydrolyzed and control chips were conducted applying constant pulping variables. The effect of pre-hydrolysis on hemicelluloses removal and sodium hydroxide consumption and pulp characteristic including total yield, reject, pulp freeness, kappa number, and pulp strengths were measured and statically analyzed. In case the effect of variable on measured property was statistically significant, then Duncan multiple range grouping of the measured property was arranged. The result revealed that pre-hydrolysis removed almost 4.2% (based on dry wood) of hemicelluloses of the wood and pre-hydrolysis demonstrated easier soda pulping delignification, due to weakening the lignin-carbohydrate bonds and both total yield, reject and kappa number were reduced. Tensile strength index of the pulp produced using pre-hydrolyzed chips war lower and as the dosage of sodium hydroxide increases, the tensile strength index was reduced initiated from the removal of hemicelluloses which is also lower than control pulp, Tear strength index of the soda pulp from pre-hydrolyzed chips was mildly reduced which is anticipated to be the consequence of fiber weakening and fiber breaking during cooked chips defibration. The effect of pre-hydrolysis variables on tear strength was not statistically significant. Based on the result of this study, hornbeam wood can be a potential source of bio-refining based on lignocellulosic material.
Pulp and paper
Farhad Zeinaly; Ali Kazemi Tabrizi; yashar Einollahi; Faraz Asadi Malek Jahan
Abstract
The first act to ameliorate bleaching process is the major elimination of lignin. Actually, the use of oxygen delignification stage before bleaching process is the essential stage in improving bleaching process and reducing process emission. In this study, the effect of conducting oxygen-delignifying ...
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The first act to ameliorate bleaching process is the major elimination of lignin. Actually, the use of oxygen delignification stage before bleaching process is the essential stage in improving bleaching process and reducing process emission. In this study, the effect of conducting oxygen-delignifying process under different process condition, on chemical, physical, mechanical and optical properties of kenaf bast kraft pulp was investigated. The kenaf bast kraft pulp with the kappa number of 22, 1154 ml/g viscosity, and 38% ISO brightness was prepared. Oxygen-delignifying treatments were carried out with three different temperatures of 90, 100 and 110°C, and two oxygen pressures of 5 and 7 bars, with and without magnesium sulfate addition. Results indicated that oxygen delignification treatment led to intense decrease in pulp kappa number, while the pulp viscosity did not change significantly. Results of measuring delignified pulp viscosity showed that the magnesium sulfate addition caused to prevention of pulp viscosity downfall. The increase in reaction temperature had a significant effect on the process improvement, but raising the oxygen pressure did not have a meaningful effect on the process. Also, the pulp brightness was increased about 7%.
Pulp and paper
Iman Akbarpoor; Hossein Resalti; Ahmad reza Saraeyan
Abstract
In this study, Deinking of old newspaper was investigated by chemical and enzymatic methods. Chemical treatment was done using chemicals at different times of 10, 20 and 30 minutes, consistency of 10%, temperature of 50±1!C along with washing, flotation and combination of washing/flotation. While, ...
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In this study, Deinking of old newspaper was investigated by chemical and enzymatic methods. Chemical treatment was done using chemicals at different times of 10, 20 and 30 minutes, consistency of 10%, temperature of 50±1!C along with washing, flotation and combination of washing/flotation. While, Enzymatic treatment was accomplished at different concentrations of 0.025, 0.05, 0.1 and 0.2% of cellulase enzyme (on the basis of oven dried waste paper), pH range of 5-5.5, different times of 10,15 and 20 minutes, consistency of 10%, temperature of 50±1!C along with washing. The results comparison of optimum chemical and enzymatic treatments showed that, deinked pulp by chemical method had higher brightness and yellowness. Also, deinked pulp by chemical method resulted the papers with higher bulk, higher caliper and higher air resistance.
Pulp and paper
Ghasem Asadpour; Hadi Boroshkian; Hossein Resalaty
Abstract
The purpose of this study is to investigate the effect of pH on cellulase enzyme activity on the drainage and strength properties of OCC pulp. Recycled OCC pulp was pretreated with consistency 0.4 percent, in constant condition the temperature is 50˚C, duration 1 hour and range pH:4-4.5, 8-8.5 with ...
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The purpose of this study is to investigate the effect of pH on cellulase enzyme activity on the drainage and strength properties of OCC pulp. Recycled OCC pulp was pretreated with consistency 0.4 percent, in constant condition the temperature is 50˚C, duration 1 hour and range pH:4-4.5, 8-8.5 with cellulase enzyme at three levels 0.1, 0.3 and 0.5 percent (according to paper pulp dry weight). The results showed that pretreatment of cellulase enhances the freeness of pulp in comparison with the control samples, but by increasing the concentration of enzyme, the freeness of pulp was reduced in pH:4-4.5 the highest freeness is at the level of 0.1 percent and in pH:8-8.5 at the level of 0.3 percent. Also, papers were evaluated for resistance properties. The results showed that the increase in the use of cellulase enzyme has increased the tensile and burst strength index. As, in the alkaline pH, the effect of the cellulase enzyme on the increase of these strength was higher than the acid pH. The OCC pulp strength tear index, only in low levels of cellulase enzyme and in acidic pH, increased strength was observed, but with increasing enzyme consumption, there was a decrease in tear strength. Also, for strength to crushing, there was no specific trend regarding the amount of enzyme and pH on enzyme function.
Pulp and paper
Hasan Davodian; Ghasem Asadpour; Seyed majid Zabizadeh
Abstract
In this study, the comparison of the use two combination of additives including the use of nano silica with cationic starch and the use of nano cellulose with cationic poly acrylamide on the physical and strength properties of cotton based paper. For this purpose, the pulp of the chemical pulp of bleached ...
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In this study, the comparison of the use two combination of additives including the use of nano silica with cationic starch and the use of nano cellulose with cationic poly acrylamide on the physical and strength properties of cotton based paper. For this purpose, the pulp of the chemical pulp of bleached cotton fibers is made with a 45˚RS grade peroxide and then the additives with specified conditions (cationic starch 1 and 1.5%, nano silica 0.3 and 0.7%, nano cellulose 1, 2 and 3% and cationic poly acrylamide 0.3, 0.5 and 0.7%) added to it and in the end 70 grams of handsheets were made. Similary, the paper was evaluated for physical and strength properties. The results indicated that the combination of cationic poly acrylamide and nano cellulose did not have much effect on increasing the majority of chemical pulp strength of cotton. As the reduction density, tensile strength, strength to tearing and no signification effect on strength to cutting. While the use of cationic and nano silica starches has significantly increased the strength and density properties of pulp paper significantly. Therefore, considering the results of physical and physical tests, it is possible to use the combination of cationic starch and nano silica to increase the chemical properties of cotton pulp.
Pulp and paper
Jalil Roshanasan; Mohammadreza Dehghani firozabadi; Mohammad Dahmardeh ghaleh no; Saeideh Sharifi
Abstract
The lignin dissolution in Kraft pulping for wheat straw was studied. Kraft pulping was carried out under the conditions: chemical charge of 18% (as NaOH, based on o.d. bagasse), sulfidity of 25% and liquor to wheat straw ratio of 10:1. Six cooking maximum temperatures of 85,100,110,120,130 and 150 ◦C, ...
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The lignin dissolution in Kraft pulping for wheat straw was studied. Kraft pulping was carried out under the conditions: chemical charge of 18% (as NaOH, based on o.d. bagasse), sulfidity of 25% and liquor to wheat straw ratio of 10:1. Six cooking maximum temperatures of 85,100,110,120,130 and 150 ◦C, were selected and reaction time varied from 0 to 250 min. based on maximum temperature. The Klason lignin, acid soluble lignin, ash and extractive contents of wheat straw were 18.4%, 2.07%, 3.24% and 4.56 respectively.
During alkaline pulping of wheat straw, about 64% and 52% of lignin was removed before reaching to the temperature 100 ◦C and 85 respectively. The values pulp and carbohydrates yield were, about 64%, 58% for 85 ◦C and 61%, 57% for 100◦C.
Chemistry of wood
Jafar Ebrahimpoor kasmani; Amir mohssen Nazeri; Ali Ashryeh
Abstract
In this investigation , effects of different humidity and heat on quality of Corrugated board , was studied , and optimum treatment indicated Variables in this Paper was : Corrugator speed (50,100,150m/min) ,wraping angle of the paper around preheaters ...
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In this investigation , effects of different humidity and heat on quality of Corrugated board , was studied , and optimum treatment indicated Variables in this Paper was : Corrugator speed (50,100,150m/min) ,wraping angle of the paper around preheaters (90,180,300 degree) and moisture of paper (6.5%,7%,8.5%). Papers that treated for this purpose was included : 125gsm kraft liner ,127 gsm medium paper and 140gsm test liner paper. A flut type of 3ply Corugated board was selected for this study.Moisture of paper was measured in 3 places : Paper on roll stand before single facer , paper after singlefacer preheater and paper before incoming doublefacer in hot plate unit. Also temprature was measured in corrugator rolls ,hot Plates in double facer and final Board after Exiting of the Machine.
Results show that , warp of final board decreased in speed 50 and 100m/min ,moisture 7% and 1800 wraping angle of the paper around preheater.
That means lower speeds and higher wraping angles cause to more heat on corrugated board and decreasing in warp content resulted.It should be noted that lower humidity more than 7% and increase wraping angle more than 180 degree cause to over drying and intensive moisture decrease in final board that cause to reverse warp in final board.
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
Jafar Azizi; Omid ramezani; Esmaeel Rasooly; Hamidreza Rudi
Abstract
Cellulosic fines are essential parts of paper making system which impart remarkable effects on the production process parameters and the quality of final product. In this study, properties of fiberfines prepared from three kinds of pulps including Kraft, chemical mechanical (CMP), and recycled (OCC) ...
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Cellulosic fines are essential parts of paper making system which impart remarkable effects on the production process parameters and the quality of final product. In this study, properties of fiberfines prepared from three kinds of pulps including Kraft, chemical mechanical (CMP), and recycled (OCC) were investigated. Required amounts of fines were prepared using Valley Beater apparatus. Then the fines were classified into three categories using dynamic drainage Jar (DDJ): fines passing a 100 mesh remained on 200 mesh (P100/R200), fines passing a 200 mesh remained on a 325 mesh (P200/R325), and fines passing a 325 mesh (P325). Fines properties including dimensional size, special hydrodynamic volume, colloidal charge, alkalinity, turbidity, viscosity, and specific area were examined. The results revealed that PH of fiber suspensions tended alkaline concurrently to the decreasing in dimensional size of fines. Additionally, the colloidal charge of the three types of fines, especially the charge associated with the fines passed through 200 mesh screen and remained on 325 mesh one, showed a different behaviour compared to those in the same classes with the adverse trend to the viscosity variation. Special hydrodynamic volume is consistent with the dimensional size and dimensional ratio with the lowest amount of it observed in the recycled pulp fines. Turbidity has a direct relationship with particles size, homogenous distribution and the specific area of the finesThe results of turbidity related to the fines passed through 200 mesh size showed different behaviour compared to other categories.
Pulp and paper
Ali Ahmadi ladjimi; Mohammad Azadfallah; Mehdi Rahmaninia; Yahya Hamzeh
Abstract
Stickies is among the major challenges in paper recycling mills. This substance deposits on paper machine components and cause to break paper web as well as loss of end product quality. So, it is necessary to control the stickies and lessen its detrimental effects. It is known that cationic polymers ...
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Stickies is among the major challenges in paper recycling mills. This substance deposits on paper machine components and cause to break paper web as well as loss of end product quality. So, it is necessary to control the stickies and lessen its detrimental effects. It is known that cationic polymers as fixing agents can control the stickies efficiently. Therefore, the control of stickies of OCC pulp using a commercial cationic polymer called GL at 0.4, 0.8 and 1.2 percent based on oven dry weight of pulp at pH 4 and pH 5 were investigated. Macro- and microstickies, dissolved and colloid substances (DCS), turbidity, and drainage time were measured to evaluate GL efficiency and compared with control sample. The results indicated that GL dosing at 0.4 and 0.8 percent in pH 4 and 7 due to flocculation and fixing the stickies onto the fiber caused to decrease in macro stickies, microstickies and DCS while improved the drainage time. Although, no efficient performance was observed in controlling stickies at higher content of GL i.e. 1.2 percent. Generally, it is concluded that with consuming at desired pH and dosage content, GL can be used as efficient agent to control stickies in processing of OCC pulp.
Pulp and paper
Hossein Resalati; Mostafa Nikkhah Dafchahi
Abstract
One of the drawbacks of utilizing non-forest fast growing species of Poplar as raw materials to produce newsprint in Mazandran Pulp and Paper Mill is fairly low bulk and opacity of produced paper at the yield of 85% (current CMP yield of the Mill). In this research work, the effect of process parameters ...
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One of the drawbacks of utilizing non-forest fast growing species of Poplar as raw materials to produce newsprint in Mazandran Pulp and Paper Mill is fairly low bulk and opacity of produced paper at the yield of 85% (current CMP yield of the Mill). In this research work, the effect of process parameters (cooking yield and freeness) on the optical and mechanical properties of chemi-mechanical pulp was investigated. The chemi-mechanical pulps of poplar was prepared at four various levels of cooking yield, through changing the cooking time, and their properties at different level of freeness were evaluated in comparison with the control sample of Mazandran Pulp and Paper Mill (75% hornbeam and 25% beech). Strength properties of the paper pulps stemmed from the cooking yields of 85.25% to 90.4% were higher and more favorable than the control sample. By contrast, the strength properties of the produced paper pulp from the cooking yield of 94.6% were inferior to prepared paper pulp from the control sample. According to the results, there is the possibility of significant improvement of the strength properties, opacity and bulk of the chemi-mechanical pulps of poplar trough controlling the process parameters like cooking yield and freeness to utilize it as raw material of newsprint production in Mazandran Pulp and Paper Mill.
