Document Type : Research Paper
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Abstract
Background and aim: Currently, in Iran, NSSC pulp and fluting paper are produced from mixed species and waste paper. Considering the forest breathing plan in recent years, competition from other industries in supplying consumable wood raw materials and as a result of price increases, this industry has faced a shortage and challenge of consumable lignocellulosic raw materials, which is currently partially supplied by using waste paper.
On the other hand, due to the cutting down of some citrus trees, especially oranges, and the expansion of kiwi cultivation in their place, large amounts of citrus wood are produced annually in the north of the country, which is mostly used in the particleboard, fiberboard, or firewood industries. Due to its good accessibility, ease and low cost of transportation, the use of these woods in pulp and paper production can also be considered and is important. For this purpose, this study was conducted to investigate the possibility of producing NSSC pulp and fluting paper from citrus wood (orange) in the Mazandaran Wood and Paper Industries (MWPI).
Materials and Methods: To conduct this research, a random amount of wood chips were prepared from citrus (orange) wood in western Mazandaran (Tonkabon region) and using the MWPI cooking conditions, NSSC pulp was prepared. In the first stage, the biometric properties of their fibers were measured. In the next step, the refined NSSC pulp of orange wood was mixed with the NSSC pulp of MWPI in proportions of 60, 45, 30, 15, 75 and 100 percent. From the selected samples and according to TAPPI standard tests, handsheets with a basis weight of 113 g/m2 was prepared. Then, the optical properties of the prepared papers, especially the brightness, yellowness and opacity, as well as the resistance properties, especially the resistance to tearing, bursting, tensile and breaking length of the resulting papers, were measured and compared using TAPPI standard tests.
Results: The results of fiber biometrics showed that the average fiber length, flexibility coefficient, and Rankel coefficient of orange wood were 734.8 microns, 46.9, and 136.02 microns, respectively. The results of this study showed that under the cooking conditions of MWPI and at a temperature of 170 degrees Celsius and a cooking time of 112 minutes, NSSC pulp can be produced with an efficiency of 76%. The results showed that the highest values of breaking length, ring crush test (RCT) and tensile strength were observed in the paper obtained from orange NSSC pulp. The highest tear, burst strengths and CMT were observed in the paper obtained from a mixture of 75% orange NSSC pulp + 25% factory NSSC pulp, and the lowest values were observed in the fluting paper obtained from factory NSSC pulp. Therefore, according to the above results, in addition to the fact that pure NSSC citrus pulp (orange) can be substituted for the aforementioned factory NSSC pulp, even with an increase of 15-100% of NSSC citrus pulp (orange) to the factory NSSC pulp, most of the above resistances show a significant increase. However, the best properties of fluting paper were observed in the paper obtained by mixing 75% orange NSSC pulp + 25% factory NSSC pulp.
Discussion: Considering that the biometric characteristics of orange wood fibers are similar to some of the hardwoods forests of the northern part of the country, and even its fiber length and Rankel coefficient are much better than many industrial hardwoods species, which has improved many of the resistances obtained. Therefore, a 75% mixture of citrus NSSC pulp (orange) can be used to replace part of the NSSC pulp of MWPI, in order to reduce the problem of gardeners regarding the more suitable sale of citrus wood (orange), and to provide the possibility of using citrus NSSC pulp (orange) instead of part of the NSSC pulp produced by the aforementioned factory. Therefore, by supplying a portion of the raw materials for the pulp and paper industries from citrus orchards in the interior (north) of the country, the outflow of a significant amount of foreign exchange from the country for the purchase and supply of raw materials for paper factories will be prevented.
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