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.
Hossein Yousefi; Elyas Afra; Davood Rasouli; mahdi mashkour
Abstract
In this study, paper and nanopaper were first produced and then treated with dodecyltriethoxysilane to prepare water repellent cellulose paper and nanopaper were made using dodecyltriethoxysilane. As the result of silane treatment, the hydrophilic surface of paper and nanopaper converted to hydrophobic ...
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In this study, paper and nanopaper were first produced and then treated with dodecyltriethoxysilane to prepare water repellent cellulose paper and nanopaper were made using dodecyltriethoxysilane. As the result of silane treatment, the hydrophilic surface of paper and nanopaper converted to hydrophobic surfaceones. The micrographs of FE-SEM confirmed the nano-scale size of cellulose nanofibers. XPS results showed that the surface of specimens contains silane. With the treatment of silane, the water droplet contact angle increased to 104 and 153 degree in nanopaper and 153 paper, respectivelydegree in paper. Because of this, the surface of treated paper can be regarded as super hydrophobic surface. TGA confirmed that the ash content of treated specimens were higher than those of untreated ones and also it was revealed that the silane treatment made a multi-layers coating on the surface of specimens. The treated specimens showed less water absorption and higher mechanical properties than untreated ones. The silane coupling treatment made water hydrophobic surfaces onof cellulose paper and nanopaper made them water-proof which can led to the development of their applications for outdoorshumid conditions.
ali ghasemiyan; khadijeh armand; Elyas Afra; ahmad reza saraeian; mina salary
Abstract
The aim of this study was to investigate the effect of coating packing paper with polylactic acid-chitosan and polylactic acid-nano-chitosan complexes in two layer by layer and composite methods. For this purpose, was used of 80 grams long fiber handsheet paper Prepared from Mazandaran wood and paper ...
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The aim of this study was to investigate the effect of coating packing paper with polylactic acid-chitosan and polylactic acid-nano-chitosan complexes in two layer by layer and composite methods. For this purpose, was used of 80 grams long fiber handsheet paper Prepared from Mazandaran wood and paper factory. For the preparation of coating material, 1% poly lactic acid in chloroform and 1% chitosan and nano chitosan in acetic acid were prepared. In both methods, up to three layers of coating were finally applied and the final layer in each treatment was poly lactic acid. The paper samples were then dried in an oven at a temperature of about 100 ° C. In the composite method, each material (chitosan and nano-chitosan) was mixed independently with poly lactic acid on a magnetic stirrer and then seating on a base paper. Finally, all papers were performed for barrier tests including contact angle measurement, water absorption (Cobb) and water vapor transmission rate (WVTR) and resistance tests including burst resistance and air penetration resistance. Based on the results, the barrier properties of the coated Samples in both methods (layer by layer and composite) were increased compared to the control sample. Also, the results of the study of composite and layer by layer methods showed that the LBL method causes more prohibition in the paper and increases the amount of prohibition with increasing the number of coating layers. It is worth noting, however, that between the second and third layers of coating, changes were less pronounced. These changes were observed in both the LBL and composite methods. Air Resistance was also increased in the coated samples.
Pulp and paper
Mahdis Shafaee; Ali Ghasemiyan; Mohammad reza Dhghani Firozabadi; Poneh Ebrahimi
Abstract
In recent years, there has been a lot of attention in producing and using of renewable and environmental friendly cellulose film and coverage. Regarding to the application of these films and coverages in different industries such as food, packaging and medical industries, their antimicrobial property ...
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In recent years, there has been a lot of attention in producing and using of renewable and environmental friendly cellulose film and coverage. Regarding to the application of these films and coverages in different industries such as food, packaging and medical industries, their antimicrobial property is apparent. The purpose of this research is producing cellulose antibacterial film. At first, long fibr pulp convert to NFC using a supergrinder and then nanosilver treated films prepared applying silver nitrate through two different ways. In the first method, silver nanoparticles with considerations of 5 and 10 ppm reduced on NFC particles’ surface using retention aid. In second methods the prepared NFC film has been immersed in solution of Ag nanoparticle in concentration levels of 5 and 10 ppm. On higher concentration of used nanosilver solution, the amount of retained Ag nanoparticle in the first method was higher than the second one whereas, on lower concentration one, the differences of retained nanosilver values between two methods was a little. It has worth of mentioning that immerging method has the benefit of avoiding Ag nanoparticle wasting during pulp draining and nanosilver solutions could be reused simply.
Pulp and paper
Sahba Aliniyay Lakani; Elyas Afra; Hossein Yousefi
Abstract
In this research, nano fibrillated cellulose, as a reinforcement nano material and environmentally biodegradable material which has recently attracted the attention of most researchers and paper producers, has been added to chemi-mechanical pulp used for manufacturing of liner board at different charges ...
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In this research, nano fibrillated cellulose, as a reinforcement nano material and environmentally biodegradable material which has recently attracted the attention of most researchers and paper producers, has been added to chemi-mechanical pulp used for manufacturing of liner board at different charges of 5, 20, 50 and 100% in two different levels of freeness. Also, the effect of wet press, one of the the most important processing agents on the properties of paper reinforced with nano fibrillated cellulose, in two levels of press pressure which included 3 and 6 bar, has been investigated. Finally, physical, barrier and strength properties of the papers produced have been measured according to TAPPI test methods. Addition of nano fibrillated cellulose was resulted in improved tensile and air resistance of chemi-mechanical pulp and increasing trend in improving of these properties with increase in press pressure was one of the important achievements of the present research.
Pulp and paper
Nazbakht Hezbi; Elyas Afra; Hossein Resalty
Abstract
In this research, the effect of different steps of enzymatic treatment including enzymatic pre-refining and post-refining by Endoglucanase was investigated on the quality of OCC pulp. Three pulps including a: control sample (without enzyme addition), b: enzymatic pre-refining (enzyme treatment + refining) ...
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In this research, the effect of different steps of enzymatic treatment including enzymatic pre-refining and post-refining by Endoglucanase was investigated on the quality of OCC pulp. Three pulps including a: control sample (without enzyme addition), b: enzymatic pre-refining (enzyme treatment + refining) and c: pre and post enzymatic refining (enzyme + refining + enzyme) were made from OCC pulps. Enzymatic treatment was done at optimum conditions before determined (concentration of 1u and time duration of 0.5 hour) under constant process conditions and refining accomplished at given revolution of 2000. Obtained results from this research indicated that applying enzymatic pre-treatment had efficient in improving the physical and mechanical of paper and showed the highest strength than to the other treatments. Using Endoglucanase at two stages (before and after refining) caused to improve pulp drainability and decrease the paper strength properties. In general, the maximum tear index was observed in enzymatic pre-refining step.
Nazbakht Hezbi; Elyas Afra
Abstract
The present study analyzed the effect of different enzymatic treatment times using endoglucanase and refining levels to improve the properties of OCC pulp. The OCC pulps were treated by endoglucanase enzyme at a constant dosage of 1u (on o.d. pulp) at different reaction times (0.5, 1, 1.5 and 2 hours) ...
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The present study analyzed the effect of different enzymatic treatment times using endoglucanase and refining levels to improve the properties of OCC pulp. The OCC pulps were treated by endoglucanase enzyme at a constant dosage of 1u (on o.d. pulp) at different reaction times (0.5, 1, 1.5 and 2 hours) under constant process conditions. Based on the results, enzymatic treatment of OCC pulp at different time levels improved the physical and mechanical properties, compared with the control pulp, and the highest improvement level was observed at 0.5 hour reaction time. Longer enzymatic reaction time (up to 2 hours) led to a significant decrease in the physical and mechanical properties of the pulp. Evaluation of different of enzymatic treatment times and different refining levels indicated that the papers produced from endoglucanse pre-treated pulp (for 0.5 hour treatment time) showed better quality at different refining levels. However, increasing enzymatic treatment times up to 2 hours showed severe decrease both the physical and mechanical properties at higher refining levels. In general, refining enzyme pre-treated pulp and also the control pulp resulted in a higher strength property of the paper.
