Narges Ramezani; Amir Khosravani; Hamidreza Rudi
Abstract
Chitosan is one of the biopolymers which possesses unique properties and has been recently considered in various applications such as paper-making. This polymer is soluble in acidic conditions and has the potential to act as a polyelectrolyte under the colloidal condition in the pulp. However, according ...
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Chitosan is one of the biopolymers which possesses unique properties and has been recently considered in various applications such as paper-making. This polymer is soluble in acidic conditions and has the potential to act as a polyelectrolyte under the colloidal condition in the pulp. However, according to the studies, the capability of this polyelectrolyte was better in alkaline condition, in improving the drainage, retention and even strength properties of paper. Therefore, in this study, the performance of chitosan was studied in different conditions and the results were investigated based on the interpretation of the adsorption process and chitosan configuration using silicon wafer model and ellipsometry technique. For this purpose, bleached kraft softwood fibers were refined to a Canadian standard freeness of 300 ml and after addition of chitosan and nano-silica at different pH levels, freeness and fines retention parameters were evaluated. The results of this study confirmed that chitosan polyelectrolyte showed a good performance in increasing drainage and retention at alkaline pH, compared to the other pH levels, lonely and with the addition of nano silica. However in freenes test at acidic pH, the addition of chitosan along with nanosilica reduced the drainage, and no significant effect was observed at neutral and acidic pHs in the case of fine retentions. In order to interpret these observations and to ratiocinate the behavior of chitosan polyelectrolyte, the data obtained from the ellipsometry technique was investigated to determine the configuration and the thickness of the adsorbed chitosan layer which showed a higher thickness of the polymeric adsorbed layer at alkaline pH, and thus, the possibility of the longer tail and loops configurations in the environment and more effective interractions beyond the electrical double layer.
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
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
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
Hamid reza Rodi; Ali Soleymanisadati; Hosein Jalalitorshizi
Abstract
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 ...
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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.
Pulp and paper
Hamid reza Rodi; Haseibeh Saeedi; Kermanian Hossein
Abstract
Improvement the strength properties of papers made from recycled fibers is of important aims in papermaking industries. Current researches revealed that higher retention of strength induced additives through alternative absorption of polymers having opposite charge is one of promising approaches to obtain ...
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Improvement the strength properties of papers made from recycled fibers is of important aims in papermaking industries. Current researches revealed that higher retention of strength induced additives through alternative absorption of polymers having opposite charge is one of promising approaches to obtain such purpose. In this study, treatment of fibers prepared from neutral sulfite semi-chemical papers with cationic starch and anionic CMC was conducted in pH~7, pH~10 and 0.001 M NaCl salty suspension. Then, fibers water retention value and zeta potential was measured. Standard handsheets with 60±3 g/m2 basis weight were made from untreated and treated pulps. The results have shown that fibers WRV significantly increased by absorbing of these two water-loving polymers. Consecutive changes of zeta potential confirmed charge reversion of fibers surface and sequential absorption of couple polymers. Scanning electron micrographs prepared from the samples of untreated and treated papers presented new variations in amount of fibers bend area due to the larger absorption of these two reinforcement polymers. Moreover, considerable development in paper mechanical characteristics (tensile, burst and tear indices) proved the success of high absorption of applied bio-polymers.
Pulp and paper
Hamid reza Rodi; Hossein Jalali Torshizi; Esmaeil Rasooly Garmaroudy
Abstract
The aim of this study was to investigate the effect of using different fillers in the presence of cationic rosin sizing agent on the properties of pulp and paper made from CMP fibers. For this purpose, cationic rosin internal sizing agent at the levels of 0, 0.5, 1 and 1.5 % based on oven dry fibers, ...
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The aim of this study was to investigate the effect of using different fillers in the presence of cationic rosin sizing agent on the properties of pulp and paper made from CMP fibers. For this purpose, cationic rosin internal sizing agent at the levels of 0, 0.5, 1 and 1.5 % based on oven dry fibers, and fillers including grounded carbonate calcium (GCC), precipitated carbonate calcium (PCC), Talc and Zeolite in 25 % level based on oven dry paper accompanied with cationic polyacrylamide retention agent at the constant level of 0.3 % based on oven dry fibers were added to the CMP pulp suspension according to the TAPPI standard. In order to examine the effect of different fillers in the presence of cationic rosin, handsheets with basis weight of about 60±3 g/m2 were prepared from each experiment. Then, various pulp and paper characteristics were measured. Statistical analysis of the results revealed that type of filler has dissimilar behavior on the pulp and paper properties in the presence of cationic rosin. Drainage time of pulp suspension was lower when adding Zeolite and GCC fillers. Talc and PCC decreased more the paper strengths properties. Ultimately optical properties of papers improved more when Talc and PCC were added to the CMP pulp. Consequently, with respect to the priority of brightness and opacity for the copy and print papers made from CMP fibers, addition of Talc and PCC in the presence of cationic rosin sizing agent may be meet more the requirements compare to Zeolite and GCC fillers.
Pulp and paper
Fatemeh Naijian; Hossein Resalati; Hamid reza Rodi; Hossein Jalali-Torshizi; Kamal Pirmoradian
Abstract
Nowadays, recycled fibers are the main fiber source for manufacturing packaging papers. Sizing of such papers, based on the type of application, is of great importance. In this research, the effect of alum-cationic rosin consumption amount in pH of about 6.5 on the properties of papers made from white ...
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Nowadays, recycled fibers are the main fiber source for manufacturing packaging papers. Sizing of such papers, based on the type of application, is of great importance. In this research, the effect of alum-cationic rosin consumption amount in pH of about 6.5 on the properties of papers made from white sheets trimmings was examined. In order to optimize consumption extent, pulp suspension sizing with alum in six level of 0, 4, 5, 7, 8, and 10 %, and rosin with the ratio of 50 % of alum based on oven dry (OD) pulp was done according to the TAPPI standard methods. Then by preparation of handsheets with basis weight of about 65±5 g/m2, their Cobb test (45 second), structural and strength characteristics were investigated. Statistical analysis of the results have shown that alum and rosin consumption amount of about 7 and 3.5 % based on OD pulp is the best suitable level for internal sizing of white sheets trimmings fibers. In these alum-rosin level, Cobb value of papers decreased from 120±11.6 g/m2 the lowest value of about 64±9.7 g/m2. Contact angle of water droplet with the paper surface increased from 24.81º to 96.53º. Paper tensile index decreased up to 125±9.7 N.m/g by such sizing level and again increased with increasing alum-rosin level. Seemingly, such phenomena can be attributed to the alum role in charge neutralizing, cellulosic fines retention and improving bonding-ability of paper network. Meaningful decrease of paper surface roughness from 10.34±0.54 µm in control sample to 8.23±1.37 µm in sized papers in optimized level confirmed this assumption.
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.
Pulp and paper
Hamid reza Rudi; Morteza Nazeryan
Abstract
In this study, the effect of using Layer-by-Layer (LbL) treated pulp as mixed with refined OCC recycled pulp was investigated on paper physical properties. The LbL treatments were conducted to build 7 consecutive cationic and anionic starch layers. Afterwards, at three levels of 10, 20 and 30 percent, ...
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In this study, the effect of using Layer-by-Layer (LbL) treated pulp as mixed with refined OCC recycled pulp was investigated on paper physical properties. The LbL treatments were conducted to build 7 consecutive cationic and anionic starch layers. Afterwards, at three levels of 10, 20 and 30 percent, LbL-treated pulp was added to the 10, 15 and 20 minutes refined pulp. From mixed pulp, handsheets with basis weight of 60 g/m2 were prepared and its physical properties including: thickness, density, roughness and formation was examined. The results of LbL treatment using AFM micrographs indicated that the surface of fibers was covered with starch polymer particles by means of Layer-by-Layer treatment. Also, SEM micrographs confirm starch impregnated fibers surface and formation of rough surfaces. Analysis mutual effect of independent variables revealed that addition of LbL-treated pulp to the refined recycled pulp had only significant effect on paper thickness and surface roughness, while variation of refining time had significant influence on all physical properties. In current research, considering the results of ANOVA test and the mutual effect of the content of LbL-treated pulp and different refining time levels on the paper physical properties using response surface methodology, adding of 10 % of LbL-treated pulp to the OCC pulp and applying the refining time of about 18.66 minutes was selected as optimum condition.
Pulp and paper
Hossein Jalali trshizy; Saeideh Zarea bidkei; Omid Rmazani; Hamidreza Rodi
Abstract
Bio and synthetic polymers; micro and recently nano particles have been applied in wet end section of papermaking industry. Very special attention is focused toward their advantages for controlling the process variables and improving the product quality made from recycled ...
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Bio and synthetic polymers; micro and recently nano particles have been applied in wet end section of papermaking industry. Very special attention is focused toward their advantages for controlling the process variables and improving the product quality made from recycled papers. In the presence of cationic starch polymer as an anionic trash reducer in the pulp slurry, the effects of cationic polyacrylamide (CPAM)-bentonite nanoparticle complex on retention, drainage and paper properties made from old corrugated container (OCC) was evaluated. The results showed that addition of CPAM polymer individually enhanced burst, tensile and tear strength indices. The application of nano bentonite following CPAM has significantly increased all of mentioned pulp and paper properties. Dewatering rate analysis by Dynamic Drainage Jar and laboratory handsheet maker revealed that the time for the paper manufacturing can be reduced. Moreover, raw material to final product ratio (total retention) increased from 96.7% up to 98.7%. Long chain cationic polyacrylamide shows high capability as the flocculation of papermaking ingredients, individually and particularly in combination with nano bentonite, especially for fines which is a high portion in the recycled pulps. Thus the problem resulting from not retaining sufficient ingredients and the pollution load of the paper mill effluent will be reduced.
