Pulp and paper
Jafar Ebrahimpour Kasmani; Ahmad Samariha
Abstract
Background and objectives: Fruit packaging cardboard protects fruits from impacts, pressure, and damage during transportation, while helping to maintain their freshness and quality. To achieve these objectives, it is essential to enhance the strength of the cardboard and minimize the interaction between ...
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Background and objectives: Fruit packaging cardboard protects fruits from impacts, pressure, and damage during transportation, while helping to maintain their freshness and quality. To achieve these objectives, it is essential to enhance the strength of the cardboard and minimize the interaction between its interior and exterior. At the same time, it must be biodegradable, durable, and environmentally friendly. Kraft paper is recognized as a suitable option for preserving the quality of fruits. Therefore, this research aims to improve the barrier and mechanical properties of cardboard by applying coatings of nano-graphene, fluorine, and zein, both separately and in combination, to provide consumers with higher quality cardboard.
Methodology: The brown kraft liner paper with a basis weight of 120 grams was obtained from the Mazandaran Wood and Paper Company. The nanographene type AO-4 was sourced from Graphene Supermarket in the USA, zein protein from Sigma Aldrich, and fluorine from Mine Kavaran Production Group. For coating, the nanographene, zein, and fluorine were weighed in specified weight percentages and mixed with 100 grams of distilled water for 30 minutes at 50 degrees Celsius, depending on the treatment conditions. Then, 2.5 grams of styrene-butadiene latex and 0.5 grams of dispersant D200 were added to the mixture and homogenized for 20 minutes at 1500 RPM. A 5% cationic starch solution was also added as a retention aid to enhance the coating. The coating solutions were applied to the paper sheets using an Auto Bar Coater (GBC - A4 GIST Co., Ltd). The physical and mechanical properties were measured according to TAPPI and ISO standards. The experimental design was completely randomized, and data analysis was performed using one-way ANOVA and Duncan's test at a 95% confidence level.
Results: The one-way ANOVA analysis indicated that there are significant differences at the 5% level among the thickness swelling, water absorption, and porosity of the 8 types of paper. The greatest thickness swelling was observed in the brown liner paper coated with graphene and fluorine, while the lowest thickness swelling was found in the control sample, with a difference of 27% between the maximum and minimum thickness swelling. The lowest water absorption was noted in the brown liner board paper coated with zein, fluorine, and nano-graphene, with a difference of 647.5% between the maximum and minimum water absorption. Additionally, the least porosity was attributed to the paper coated with nano-graphene, showing a difference of 7365.8% between the maximum and minimum porosity. Density analysis revealed that the highest density was observed in the sample coated with zein and nano-graphene, with a difference of 14.5% between the maximum and minimum density. Furthermore, the highest surface smoothness was recorded in the paper coated with nano-graphene and zein, with a difference of 23.9% between the maximum and minimum surface smoothness. For the tensile and tear resistance index, no significant difference was observed at the 5% level, with differences of 15.5% and 26.4% between the maximum and minimum tensile and tear resistance indices, respectively. However, for burst resistance, the lowest value was found in the paper coated with fluorine and zein, with a difference of 14.2% between the maximum and minimum burst resistance. In terms of ring crush test, the highest resistance was related to the paper coated with zein, fluorine, and nano-graphene, with a difference of 16.1% between the maximum and minimum ring crush test.
Conclusion: The goal of food packaging is to extend shelf life and protect against spoilage factors. Paper and cardboard, as packaging materials, have specific advantages and disadvantages, including a lack of resistance to moisture. This research addresses the improvement of the physical and mechanical properties of kraft liner paper for fruit packaging and has demonstrated that coating increases thickness swelling and reduces water absorption. These coatings enhance the prevention of water absorption by penetrating the pores of the paper. Various factors affect water permeability, including the paper structure and the type of coating. The use of nano-graphene and zein leads to a reduction in paper porosity and an improvement in its mechanical properties. In this study, coating the paper with nano-graphene and zein significantly increased barrier properties and improved paper quality. Additionally, the results indicate that these compounds can help reduce water absorption and porosity of the paper.
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.
Mania Jadidi; Noraldin Neghad; Majid Zabihzadeh
Abstract
This research was conducted to find a procedure to increase the optical and strength properties of papers made from oxidized waste newspaper fibers. Samples of waste newspapers were randomly selected and deinked, then one part of deinked pulp was refined. Both refined and unrefined recycled pulp ...
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This research was conducted to find a procedure to increase the optical and strength properties of papers made from oxidized waste newspaper fibers. Samples of waste newspapers were randomly selected and deinked, then one part of deinked pulp was refined. Both refined and unrefined recycled pulp were divided into two groups. In each case, a group of pulps was used to make standard hand sheets (control samples) without hydrogen peroxide treatment and only adding 2% cationic starch. Second group was subjected to different percentages of hydrogen peroxide (2%, 3% & 4%) in alkaline conditions, then 2% cationic starch was added to oxidized fibers prior to hand sheeting preparation and then standard hand sheets were made. Opticaland strength properties of all hand sheets were determined according to TAPPI standards. Also FTIR spectra was taken to specify the effect of oxidation on surfaces of pulp fibers. Results showed that treatment with oxidizing agent increased the strength indices of papers. This increase was more evident when 3% hydrogen peroxide was applied. The strengths of the control samples were the lowest. Moreover, refining imposed the positive effect on strength properties. Results of optical properties measurements indicated that as the extent of treatment for both refined and unrefined pulps increases, the brightness increased, and both the yellowness and opacity decreased. The highest brightness was reached when 3% peroxide was used. Also refining results in increased in brightness and yellowness but decreas opacity. FTIR spectra showed that samples of oxidized pulp had the greatest absorption at wave number of 1650 which pertains to carboxyl group.
Pulp and paper
Said mohammad Mazhari mosavi; Saeed Mahdavi; Syed zyaldin Hosseini; Hossein Resalti; Hossein Usefi
Abstract
This research is aimed to study the possibility of rapeseed straw (Hayolla401) pulping and its paper characteristics, using Soda-AQ process. The average fiber length was found 1.04 millimeter and the average fiber diameter, lumen and thickness were found 28.00, 19.09, and 4.91 micrometer, respectively. ...
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This research is aimed to study the possibility of rapeseed straw (Hayolla401) pulping and its paper characteristics, using Soda-AQ process. The average fiber length was found 1.04 millimeter and the average fiber diameter, lumen and thickness were found 28.00, 19.09, and 4.91 micrometer, respectively. Cellulose, lignin, extractive material (acetone solved) and ash were measured 41.66, 16.00, 1.63, and3.46 percent, respectively. Cooking condition was determined as follow: Soda as 16, 18, and 20 percent on the basis of rapeseed dry straw, temperature was set at 175 and 185 Cº, cooking time was set at 40 and 70 minutes, and straw to liquid ratio was set at 1/8. The amount of anthraquinone added to cooking liquor was 0.2%, based on rapeseed dry straw. Using severe cooking factors caused reduction of yield and Kappa number in both methods. Refining was performed on selected pulps in order to reach 35025 (ml,CSF) freeness. The 60 gr/m² hand sheets were made in order to determine mechanical strength and physical properties. Average thickness, density and bulk is measured at 86.4µ, 0.69gr/cm³ and 1.44cm³/gr respectively. Average tear index, burst index, breaking length and tensile indexare measured at 4.6 mN.m²/gr, 3.5 kpa.m²/gr, 7.4km and 72.6Nm/g respectively.
The results showed that however screen yield of rapeseed straw pulp is low but kappa number and mechanical properties of pulp is suitable,compared with the other agriculture residues, so Rapeseed pulp can be used in paper making industries.
