Pulp and paper
moghadase akbari; Elyas Afra; Mohammadreza Dehghani Firouzabadi; Seyed Majid Zabihzadeh
Abstract
Background and Objectives: Plastic packaging is considered one of the most important sources of environmental problems due to its slow decomposition. To address this issue, biomaterials have garnered attention for their quick decomposition and renewability. In this context, the use of cellulose fibers ...
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Background and Objectives: Plastic packaging is considered one of the most important sources of environmental problems due to its slow decomposition. To address this issue, biomaterials have garnered attention for their quick decomposition and renewability. In this context, the use of cellulose fibers in packaging is preferred over plastic. However, the main challenge of using cellulose fibers in packaging production is their poor water resistance. This issue can be improved with a suitable bio-coating, which has inspired the current study. The aim of this study was to use a simple method to prepare hydrophobic paper that is environmentally friendly with a biopolymer.Methodology: The raw material used to make handsheets was bleached softwood Kraft pulp from the Pars paper mill. The Canadian Standard Freeness (CSF) of refined paper decreased from 750 ml CSF to 350 ml CSF. To enhance strength properties, the fibers were treated with carboxymethylcellulose (CMC) in the presence of electrolyte (CaCl2). A suspension of untreated (70%) (LF) and CMC-treated (30%) cellulose fibers was used to make handsheet paper (MLF) with a grammage of 60 g/m2. To prepare the emulsion, beeswax was melted in hot water at different concentrations (1, 5, 10, 15, and 20%), then dispersed in water using ultrasound for 9 minutes with an amplitude of 100. The paper was air-dried, immersed in different concentrations of beeswax emulsion, and then heat-treated at various temperatures (25, 60, 70, 80, and 90 ⁰C). The effect of thermal treatment on the efficiency of beeswax was examined by measuring water absorbency time and water contact angle for all treatments, with 70 ⁰C identified as the optimal temperature. The next step is to evaluate the effect of different concentrations of beeswax on properties such as water absorption (cobb), thickness, grammage, tensile strength index, brightness, and opacity.Results: Compared to untreated paper, the water absorbency time and water contact angle of all paper treated with different concentrations of beeswax at various temperatures (25, 60, 70, 80, and 90 ⁰C) increased significantly. The contact angle of handsheets treated with beeswax increased significantly with the temperature of thermal treatment. The highest water contact angle was achieved with handsheets immersed in 20% beeswax and heat-treated at 70 ⁰C. However, further increases in temperature beyond 70 ⁰C did not significantly affect the water contact angle of the paper samples. The water absorption in LF and MLF papers was 65.96 g/m2 and 7.96 g/m2, respectively. Treatment with beeswax reduced the water absorption rate compared to the control treatment at all concentrations. Paper coating increased the thickness and grammage of the paper, which increased with higher concentrations of beeswax emulsion. The tensile strength index increased after using modified fibers with CMC compared to LF paper, but coating with beeswax emulsion decreased the tensile strength index of the paper. MLF treatment and beeswax-coated paper had higher brightness compared to LF paper. Immersion in beeswax slightly decreased opacity, but this change was not statistically significant.Conclusion: The results indicate that the barrier characteristics in samples covered with beeswax improved compared to the blank sample. The study demonstrates the efficient, simple, and cost-effective production of hydrophobic paper as a biodegradable material. A key advantage of this method is the absence of chemicals containing flora or organic solvents in the preparation, making it suitable for industrial applications and meeting the requirements for sustainable development through the use of green ingredients.
Chemical conversion
Zahra Razmpour; ghasem asadpour; kermanian hossein; omid ramezani; Seyed Majid Zabihzadeh
Abstract
Sticky contaminants represent one of the biggest technical challenges in the paper recycling process. These contaminants reduce paper strength, cause plugging of wires and felts, and stick to or deposit on machine parts affecting the runnability of the paper machine In this study, firstly, the sticky ...
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Sticky contaminants represent one of the biggest technical challenges in the paper recycling process. These contaminants reduce paper strength, cause plugging of wires and felts, and stick to or deposit on machine parts affecting the runnability of the paper machine In this study, firstly, the sticky deposit of Docter blade dryer blades was subjected to multi-stage extraction with alcohol, aceton, toluene, and tetrahydrofuran solvents respectively. Then the nature of the resulting material and its physicochemical properties was investigated with FTIR analysis, GC-MS, TGA, XRF, SEM.. The results showed that the deposite originates from fiber, polymers such as polyvinyl acetate and styrene butadiene, which are components of hot melt adhesives, and fatty acid/resin esters. Fatty acids and resins are the most common organic compounds in stickies deposite. the possible origin of these compounds are chemical substances (saponified fatty acids), deinking steps and some resins and fatty acids used in the formulation of adhesives or more resistant resins and extractive materials related to Cellulose fibers. The observed minerals are mainly calcium, iron, silica and aluminum, which are present in the formulation of fillers and coating pigments during the papermaking process
Pulp and paper
Zahra Razmpour; ghasemg asadpour; kermanian hossein; omid ramezani; Seyed Majid Zabihzadeh
Abstract
Efficient approaches to eliminate or neutralize stickies is one of the topics of recent research. In the current study, some of the most conventional chemical and physical strategies in controlling these contaminants were compared. Control of micro-stickies originated from recycling of OCC using some ...
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Efficient approaches to eliminate or neutralize stickies is one of the topics of recent research. In the current study, some of the most conventional chemical and physical strategies in controlling these contaminants were compared. Control of micro-stickies originated from recycling of OCC using some selected physical approaches (washing, washing-flotation, flotation-washing and flotation) and some selected chemical methods by 4 fixing agents (Alum-PAC-pDADMAC-Cationic Starch) at 0.1-0.5-1 % dosing levels based on oven-dry weight of pulp were investigated. Electrical conductivity, TDS, turbidity, dissolved and colloidal substances (DCS) and COD were measured and compared to evaluate the efficiency of each approaches of micro- stickies removal. The results indicated that the lowest value of electrical conductivity and TDS in the physical methods was related to the flotation-washing stage and in the chemical methods was related to cationic starch 1%. The lowest amount of turbidity in the physical methods was observed in the washing and washing-flotation. Besides, the potential of secondary stickies was the lowest in the washing stage, while the flotation method had the highest potential of secondary stickies. Among the different dosing levels of the fixing agents, the lowest level of turbidity and DCS was determined for pDADMAC with 0.1% addition level, and the lowest amount of potential of secondary stickies was observed for Alum with 0.5% dosage. Both in the physical and chemical methods turbidity and DCS in pH4 was more than neutral pH. In the chemical approach with cationic starch dosage at 1% and in the physical method with the washing-flotation stage, the lowest amount of COD was reached
shaghayegh rezanezhad; Hossein Resalati; Seyed Majid Zabihzadeh
Abstract
Biodegradable magnetic nanocomposites of cellulose have been widely used in adsorption of heavy metals from water. In this research, nano magnetic papers were produced by commercial craft long fiber (NMP), magnetic fibers with 1% gluconic acid (NMP / GA 1%), nanocrystalline cellulose (MNCC) as well as ...
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Biodegradable magnetic nanocomposites of cellulose have been widely used in adsorption of heavy metals from water. In this research, nano magnetic papers were produced by commercial craft long fiber (NMP), magnetic fibers with 1% gluconic acid (NMP / GA 1%), nanocrystalline cellulose (MNCC) as well as carboxymethyl cellulose (MCMC), and the adsorbents were used to remove heavy metals of lead (Pb) and nickel (Ni). The nanocomposites were evaluated by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and sample vibration magnetometer (VSM). X-ray diffraction patterns showed that magnetic fibers and composites were successfully produced and the nano magnetite peaks were observed in all samples. Examination of nano magnetite and cellulose nanocrystals showed that most of the particles were in the range of 1 - 19 and 1 - 65 nm, respectively. The highest magnetic saturation was related to the nanocrystalline cellulose magnetic composite. Adsorption samples were examined by a microwave plasma atomic emission spectrometer. The results of lead and nickel adsorption test showed that the NMP / GA 1%, MCMC and control sample adsorbents had highest and lowest amount of lead and nickel adsorption, respectively. Lead metal also has a higher adsorption than nickel with all the adsorbents.
shaghayegh rezanezhad; Hossein Resalati; Seyed Majid Zabihzadeh
Abstract
The most important challenges of using minerals and fillers in the papermaking process are low retention and sharp reduced paper strength properties. In this research, magnetic papers were synthesized using commercial kraft fibers and iron salts. Nano-iron oxide has the same performance as fillers, as ...
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The most important challenges of using minerals and fillers in the papermaking process are low retention and sharp reduced paper strength properties. In this research, magnetic papers were synthesized using commercial kraft fibers and iron salts. Nano-iron oxide has the same performance as fillers, as a result, to prevent reducing strengths properties and retention of material in the final paper, chitosan uses as a strength agent and retention aid at 0, 10 and 15% levels. Characteristics of magnetic papers were investigated by atomic force microscope, scanning electron microscope, X-ray diffraction and vibration sample magnetometer. Tensile index and tear index were also determined in magnetic paper samples. The results of the microscopic examination showed that the magnetite nanoparticles were in the size range of 1 to 84 nm and the magnetic materials completely covered the fibers surface. Also, increasing chitosan content, increased the degree of loading and magnetic saturation of the samples. The magnetic paper samples had super para magnetic behavior. The results showed that adding chitosan at 10% increased tear and tensile strength but 15% chitosan decreased the strengths properties of magnetic paper.
Physics and Mechanical Wood
Faezeh Farhadi; Seyed Majid Zabihzadeh; foroogh dastoorian
Abstract
Extensive application of heat treated wood in exterior uses with high relative humidity and high temperature circumstances, necessitates the study of mechanical and creep behavior of them at such situations. The general objective of the present study was investigating the effect of test temperature on ...
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Extensive application of heat treated wood in exterior uses with high relative humidity and high temperature circumstances, necessitates the study of mechanical and creep behavior of them at such situations. The general objective of the present study was investigating the effect of test temperature on creep behavior of heat treated velvet maple wood. Heat treatment was conducted on oven dried maple wood samples at three temperature levels of 160, 175 and 190oC. Four-point static flexural test was conducted for determination of the required load level for creep test in three replications at each treatment temperature levels. For conducting creep tests, three levels of test temperature of 21, 40 and 60oC and duration of 65 hours were considered. Results of flexural test showed that heat treatment led to decreasing the rupture modulus compared to the control one; however, the elastic modulus did not change significantly. Results of creep test showed that with increasing test temperature, instantaneous and creep compliance values increased. With increasing treatment temperature, creep compliance was increased as well. Anti-creep efficiency ratio for evaluating the effect of test temperature on creep value at different levels of treatment showed that generally heat treatment led to decreasing the creep strength compared to the control ones. Heat treatment at temperature of 160oC led to in improvement in creep behavior at higher test temperature, in which the reason was attributed to increase of cellulose crystallinity and lignin condensation reaction, in turn led to lower plasticization of wood at higher test temperature.
Chemical conversion
Milad Poladi; Seyed Hassan Sharifi; Seyed Majid Zabihzadeh; Mostafa Nikkhah Dafchahi
Abstract
Cellulose is the most abundant bio-polymer and also has many potential and applications, Therefore, in order to convert it to solvable cellulose in many commercial solvents, it is necessary to modify the cellulose structure with a variety of methods of derivation. Cellulose derivatives have an increasing ...
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Cellulose is the most abundant bio-polymer and also has many potential and applications, Therefore, in order to convert it to solvable cellulose in many commercial solvents, it is necessary to modify the cellulose structure with a variety of methods of derivation. Cellulose derivatives have an increasing share in the cellulosic products marketing and it is used in various industries such as sanitary, pharmaceutical, food and industrial., Carboxymethyl cellulose is one of the most important commercial cellulose ether derivatives. The purpose of this study was to investigate the conversion of alpha-cellulose derived from the Deltoides pine species into a useful and more valuable product that called Carboxymethyl cellulose. In order to optimize and investigate the interaction of different process variables, response surface methodology (RSM) was used. For modeling the process, important operational parameters such as concentration of NaOH, ratio of Monochloroacetic acid to cellulose, temperature and the time of etherification as independent variables and the degree of substitution of the samples were considered as the desirable response. Analysis of variance and response level were used to create a function between variables and responses, and optimal conversion conditions were determined. The results showed that the best value presented in the optimal condition proposed by software for the degree of substitution was 31 percent for concentration of etherification, 1.09 for the ratio of Monochloroacetic acid to cellulose, 60 °C for the etherification temperature and 157 minutes for the etherification time.
