Pulp and paper
soleiman zaheri; Ali Ghasemian; Mohammadreza Dehghani Firouzabadi; Ghasem Asadpur
Abstract
AbstractBackground and Objective:Cellulose-based paper is an important renewable resource composed of cellulose, hemicellulose, and lignin. Due to its advantages such as lightweight, flexibility, low cost, and environmental friendliness, it is widely used. However, cellulose-based paper is inherently ...
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AbstractBackground and Objective:Cellulose-based paper is an important renewable resource composed of cellulose, hemicellulose, and lignin. Due to its advantages such as lightweight, flexibility, low cost, and environmental friendliness, it is widely used. However, cellulose-based paper is inherently flammable. As a result, modifying paper with organic flame retardants is of great significance to reduce fire hazards and expand the application range of cellulose-based paper. This study investigates the effect of diammonium phosphate and nanoclay, in combination with cationic starch, on the properties of paper produced from bagasse soda pulp.Materials and Methods:For this purpose, paper was obtained from bagasse soda pulp at Pars Paper Factory, with a basis weight of 120 g/m² and an average thickness of 0.185 mm. The paper was then coated with different concentrations of diammonium phosphate and nanoclay (10, 20, and 30%) along with 10% cationic starch. The coating process was carried out using an Auto Bar Coater, and the samples were dried in an oven at 60–65°C for 10 minutes. After drying, the samples were kept at room temperature for 2 days. Various tests were conducted on the samples, including liquid penetration resistance (Cobb test), thickness, contact angle, tensile strength, burst resistance, and tear resistance. Additionally, the fire-related properties of the paper, including thermal stability, burning behavior, and vertical flammability, were evaluated.Results:Coating paper with diammonium phosphate (DAP) and montmorillonite nanoclay in the presence of cationic starch improved the paper's hydrophobic properties and flame resistance. However, overall, the DAP-coated papers demonstrated better performance compared to those coated with nanoclay. This superiority is due to the formation of uniform layers and the blockage of surface pores, which prevents water penetration and increases hydrophobicity compared to nanoclay-coated and control samples. The use of DAP at an optimal concentration of 20% increased tensile strength but led to a reduction in tear and burst strength. At higher concentrations, this coating played a more effective role in enhancing the mechanical properties of the paper.Increasing the concentration of diammonium phosphate to 30% significantly increased the char yield, indicating improved thermal resistance of the paper. Both coating materials reduced the thermal decomposition temperature and increased the char yield, acting as barriers to prevent further combustion. In vertical flammability tests, DAP-coated papers at higher concentrations exhibited shorter ignition times and lower char lengths, displaying self-extinguishing behavior.The results of Fourier-transform infrared spectroscopy (FTIR) confirmed the flame-retardant performance in the condensed phase. Furthermore, the thermogravimetric analysis (TGA) of the samples showed that the treated samples had the highest char residue percentage compared to the control sample. The flame propagation pattern analysis also indicated improved fire resistance properties in the treated samples compared to the untreated ones. Additionally, all strength properties (such as tensile strength, burst strength, and tear strength) improved in the treated samples.Overall, this study demonstrated that coating with diammonium phosphate and nanoclay in the presence of cationic starch significantly improves the physical and flame resistance properties of bagasse paper. Notably, using DAP at a 30% concentration increased the char yield to 48.165%, equivalent to a 133% increase compared to the control sample and a 111% increase compared to nanoclay. These findings confirm that modifying paper made from bagasse soda pulp with this combination enables the production of paper with high flame-retardant properties, favorable char yield, and no emission of harmful substances such as halogens or formaldehyde.Conclusion:Overall, the use of diammonium phosphate and nanoclay in the presence of cationic starch as coating materials can improve the physical and mechanical properties of bagasse-based paper and make it more suitable for flame-resistant applications. Thus, these treated paper sheets can be used as fire-resistant paper-based materials.
Pulp and paper
Ahmad reza Saraeyan; Somayeh Heidari; Ahmad reza Shakeri
Abstract
Increased environmental concerns over the use of certain synthtic packaging in combination with consumer demands led to increased interest in alternative packaging materials research. Paper is biodegradable and widely used in packaging applications therefore perfectly safe for the environment. In an ...
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Increased environmental concerns over the use of certain synthtic packaging in combination with consumer demands led to increased interest in alternative packaging materials research. Paper is biodegradable and widely used in packaging applications therefore perfectly safe for the environment. In an effort to produce more environmentally friendly materials, renewable and biodegradable biopolymers have been utilized as paper coating substances. in this study carried out to determine effect of the four type of biopolymers such as anionic starch, chitosan, polyvinyl alcohol and etylenvinyl alcohol, on the smoothness, Water absorption, air resistance, burst Index properties paper made of bagasse soda pulp. Coating done whith coater tester. Coating weight was 3-6 g/m2. The results of the mechanical and physical properties of the handsheets showed that, led to increase index burst handsheets coated with etylenvinyl alcohol and anionic starch indices as 34.4 and 26.26% compared to control sample. Air resistance and smoothness was for coated paper with starch more than control sample indices as 173.23 and 18.73%. also coated paper with chitosan showed minimum value..
Pulp and paper
Farhad Zeinaly; Ahmad Reza Saraeian; Mohammadhadi Aryaei monfared; Ali Kazemi Tabrizi
Abstract
In conducting environmentally friendly processes for pulp production, first step is to reduce the effluent pollution load in each stage, and because the bleaching process is the most polluting stage in the production of pulp, improving it is one of the most important matters. The first act to ameliorate ...
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In conducting environmentally friendly processes for pulp production, first step is to reduce the effluent pollution load in each stage, and because the bleaching process is the most polluting stage in the production of pulp, improving it is one of the most important matters. The first act to ameliorate bleaching process of chemical pulps is the reduction of colored materials, mostly lignin, which enter to the bleaching section. Thus, the use of oxygen delignification stage after pulping and before bleaching process is the key stage in improving process and cleaner production. In this study, the effect of conducting oxygen-delignifying treatment by two kinds of machines, and under different process condition, on chemical, physical, mechanical and optical properties of bagasse soda pulp was investigated. The bagasse soda pulp with the kappa number of 20, 955 ml/g viscosity, and 37% ISO brightness was prepared from Pars Hafttapeh Company. 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, by two kinds of machines. Results indicated that oxygen delignification treatment led to intense decrease in pulp kappa number, while the pulp viscosity did not change. 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. The pulp brightness was increased about 4-6%. And also, due to the need of shorter time in order to reach the reaction temperature in the Iranian made machine, pulp delignifying by this machine was a little lower than Quantum machine.
