مجله تحقیقات علوم چوب و کاغذ ایران
سال سی و ششم شماره 4 (پیاپی 77، زمستان 1400)

This study uses soda lignin to modify it with furfural as adhesive on the physical and mechanical properties of plywood Poplar wood. Producing plywood, pure Lignin (L.100%), lignin-furfural 30% (L.70-F.30), lignin- furfural 60% (L.40-F.60) were used as the adhesive at three different levels ( 120 140 160gm2) accompanied with ammonium chloride (1%) as the hardener and wheat flour (30%) as the filler based on the dry weight of the adhesive. Plates made with urea formaldehyde resin at 160 g/m2 were produced as control samples. characteristics of adhesives included solid material percentage, viscosity, specific weight and PH were measured. After producing the laboratory boards, the physical and mechanical properties of samples, such as thickness swelling after 2 and 24 hours of being soaked in water, shear strength, modulus of rupture, and modulus of elasticity were measured. The results indicate that independent and interactive effects of adhesive and its consumption level on the physical and mechanical properties of plywood are not statistically significant. And in all cases, the control boards had better properties than the lignin adhesives

In this study, the effect of epoxy resin modified by carbon nanofibers (CNFs) was investigated at three levels of zero, 0.4 and 1.5% on the strength properties of common corner joints in the furniture industry. Carbon nanofibers were dispersed in the adhesive polymer matrix by ultrasonic device and test specimens of joints were prepared using cut MDF pieces with desired dimensions and wooden dowel with diameters of 8 and 10 mm and penetration depth in two levels (D2 and D3) and using reinforced epoxy by CNFs. A total of 12 treatments with three replications were evaluated separately for each of the compressive and tensile tests and the flexural moment capacity of the joints specimens was evaluated at a speed of 3 mm/min. The results showed that by increasing the percentage of CNFs, diameter and penetration depth of dowel wood in the compression test, the flexural moment capacity 1.2,, 1.2 and 1.2 times, and in the tensile test 1.3, 1.1 and 1.2 times, respectively, increased compared to the control samples. In general, according to the research variables, it can be said that carbon nanofiber was able to improve the strength properties of epoxy resin and thus the joints. The level of 0.4% CNFS, diameter 10 mm and penetration depth of D2 dowel wood had the best effect on the strength of joints in two types of loading

In this study, the effect of cellulose nanofibers on the properties of handmade papers produced from hemp and wood pulp fibers was assessed. Also, the nanofiber application as a strength enhancer for restoration of handmade papers was investigated. Firstly, handmade paper samples were prepared. Cellulose nanofibers with weight percentages of 0.5, 1 and 2% were prepared as a suspension in water the samples were treated by the suspensions. Blank and treated samples were tolerated accelerated aging process and then pH, colorimetric and tensile strength tests were performed. Comparison of blank and treated samples results showed that the tensile strength of the both groups of hemp (H) and wood pulp (WP) papers were increased after treatment by cellulose nanofibers. Aging process caused to reduction in tensile strength of treated samples but it was increased in comparison with blank samples before and after aging. The pH of the papers in both groups was in the alkaline range after the treatment and aging. Brightness of papers was increased after the treatment and color changes in the samples were due to their accelerated aging conditions.

The aim of current research was to investigate physical and mechanical properties of particle board made from pistachio lignocellulosic residue. The raw materials were prepared from Sirjan (Kerman province). Sample boards were made from pistachio lignocellulosic residue at two press time (4 and 5 minutes), two press temperature (170 and 180ᴼc) and three compositions (100 percent, 90:10 and 80:20 pruning residue to pistachio shell). The specimens were physically and mechanically tested as water absorption, thickness swelling, bending strength, modulus of elasticity and internal bonding. Afterward, the results were analyzed based on a complete randomized design (CRD) under a factorial experiment. Results revealed that pruning residues of pistachio trees can be used as suitable raw materials for particle board production. Moreover, pistachio shell can be used up to 10 percent in raw material composition, but physical and mechanical properties of boards will be reduced in higher consumption quantities.Keywords: Particle board, pruning residue, pistachio shell, composition, physical and mechanical properties

The first step in feasibility study of any national mega projects in energy sector is the investigation on the production potential and evaluate the market demand for the product. The success rate of a biofuel project after forecasting supply and demand depends on choosing the appropriate place to produce. In this respect, factors such as the selection of appropriate production site, environmental, technical, economic and social are among major issues. In this study, autoregressive integrated moving average (ARIMA) model was used for the prediction of bioethanol demand in five sceneries; E5, E10, E15, E20 and E30. The time period up to 1412 is foreseen. The data on agricultural wastes and the present and future potentials for the bioethanol production in different provinces is analyzed. The results indicate that, the average daily consumption of gasoline will increase to 136,922 million liters per day as we reach 1412.The study also shows that there exists the potential for the production of 18.16 million liters of bioethanol which can fulfill the requirement of E5 and E10 by 1412. If we want to implement the E20 and E30 scenario in the country, it is necessary to increase the production of 7 selected products in this research, in the provinces of Khuzestan, Fars, Khorasan Razavi, Golestan, Isfahan, Mazandaran, Tehran, Qazvin and Alborz and Gilan by 62.2 million tons per year by 1412, And consider the effective factor in the success of the project, namely the support of the government and legislators for national mega projects.

The paper industry plays an important role in the culture, economy and development of countries. Due to the lack of appropriate conditions, Iran has no advantage in producing various products of this industry. Therefore dependence for imports is obvious. On the other hand Iran has many problems in foreign exchange market. Which the most important is the limitation of foreign exchange reserves. This problem puts a heavy pressure on reserves and creates serious restrictions in the imports of all goods. Severe Sanctions have exacerbated that problem these years. Then identifying a good policy against, is necessary. Therefore, the aim of this study is to investigate how the exchange rate affects the import of the paper goods in order to find a fine strategy. This study considers the effect of exchange rate on import demand of paper in the period (1999-2019) using Auto-Regressive Distributed Lag (ARDL) and Error Correction Model (ECM) to investigate both short and long-term relationship of imports in the paper goods. The results show that paper products in Iran are Essential, their import demand is respectively affected by oil revenues, effective exchange rates, tariffs and value added and the import of all paper products are less elastic to the exchange rate. When the exchange rate falls, imports of paper products increase. Therefore in a situation where the country cannot cover the total needs and the economy faces severe foreign exchange reserves restrictions on imports, so the best policy is to increase recycling capacity in the country. This means that increasing recycling can reduce extra pressure on foreign exchange reserves. Also, the short-term relation with a coefficient of 1.152 moves toward the long-term equilibrium and there is a stable long-run equilibrium and relation between the variables of the model.

This study was aimed to investigate the effect of polyalumium chloride and ‎nano-chitosan on optical and mechanical properties of chemi-mechanical pulp. For this purpose, some of the bleached CMP pulp of Mazandaran Wood and Paper Industries (MWPI) were randomly selected as a control sample. In addition, the polyalumium chloride were used as a white powder at 4 levels of ‎0, 0.5, 1, and 1.5%. The nano-chitosan was then added to the CMP pulps suspensions at 3 levels of 0, 1, and 2%, as well. Hand-sheets with a basis weight of 60 gr/m2 were prepared from the mentioned pulps. The optical and mechanical properties were then measured and compared using TAPPI standard test methods. The results showed that by adding polyalumium chloride and nano- chitosan(separate) to the CMP pulps, brightness, opacity, greenness,tear, tensile, burst strengths, air resistance‎ ‎increased , but Cobb 60 and a* factor ‎decreased. On the other hand, with the addition of nano-chitosan and polyalumium chloride to CMP pulp, the brightness and greenness increased, but tensile, burst, tear strengths, air resistance, Cobb 60 and opacity low decreased and then suitable increased. Moreover, the findings showed that by simultaneous adding 1% polyalumium chloride and 2% nano-chitosan(separate) and 2% nano-chitosan with 1.5% polyalumium chloride to the CMP pulp, most of the paper properties were improved. Therefore, ‎it can also be introduced as the best treatment.

One of the most common types of paper and paperboard production in Iran, is the production of various grades of liner, test liner and corrugated medium from recycled old corrugated containers (OCC) pulp. With the increase in population, rise of consumption rate and start of new paper production mills, the shortage of raw and fiberous materials in the paper industry is becoming more noticeable. On the other hand, the shortage of wood in the country has been introduced as a driving force for paper recycling industry. Meanwhile, due to the sharp currency fluctuations and the rise in the of imported long fiber price, consumption of virgin fibers as well as imported long fibers has been limited. Therefore, unfortunately, for many reasons, the quality of such paperboards in the most of domestic production mills are not competitive with similar imported products. Therefore, the potential of achieving desirable properties through fiber classification of OCC by Bauer McNett apparatus and removing fine fiber fractions through fractionation (prior to refining) was considered. The results showed that tensile and tear indices increased significantly with the removal of tiny materials such as fines and fillers. This increase was such that the paperboards without fines and fillers not only compensated for the lack of long fibers but also resulted comparable strength properties.

Surface sizing of historical papers by starch sizing was performed with the aim of investigating the effect of this material on the aesthetic and mechanical properties of historical papers. For this purpose, starch sizing with a weight concentration of 3% were used and pH, colorimetric, angle of contact and tensile strength tests were performed before and after aging of the samples. The results showed that the pH of samples non-sizing and samples containing starch sizing decreased after aging but it is still in the alkaline range. The brightness of the samples was slightly reduced after sizing with starch before and after aging and the color of the samples tends to darken. Tensile strength of paper samples containing starch sizing before and after aging increased compared to samples non-sizing. The results of measuring the angle of contact also showed that starch sizing no effect on increasing the resistance of paper to wetting and does not prevent the surface of the paper from getting wet.

This study and it aim was accomplished on cationic starch and nano-clay(bentonite) on physical and mechanical properties of old recycled pulp. For this purpose, first some of old recycled pulp were randomly selected from Kaveh Industries in Saveh city as control. Then, nano-clay used in 0, 0.3 and 0.6 % levels. The cationic starch were added in 0, 1, 1.5 and 2 % levels and imported long fibers with 0 and 15 % levels to old recycled pulp suspensions. The hand sheets were prepared from above-mentioned of pulps with 140 gr/m2 basis weight and then the phesical and mechanical properties were measured and compared according to TAPPI standard test methods. The results showed that tear, tensile, burst strengths and ring crust test and corrugated medium test were increased and cobb 60 and thickness were decreased. The results showed that all physical and mechanical properties improved with 5% addition 15% imported long fiber. The results showed that using 2 cationic starch with 0.6 % nano-clay and 15% imported long fiber improved the most paper properties, too.