مجله صنایع چوب و کاغذ ایران
سال دهم شماره 1 (بهار 1398)

In this study, a bagasse bleached paper-grade pulp from Pars pulp and paper mill was subjected to xylanase (X) treatment and combined with cold caustic extraction (CCE). The positive effect of the enzyme was observed on the removal of hemicelluloses and with increasing the dosage of xylanase treatment (0.01-0.05 g/g pulp), the extraction of hemicelluloses from the pulp increases, but there is still high remaining hemicelluloses in the pulp. The xylanase treatment increased the polydispersity index (8.21-8.46) resulting in a broader molar mass distribution. High molecular weight cellulose fraction (DP>2000) increased by the xylanase treatment and the highest amount was thus observed by 0.05 dosage of the enzyme. The cold caustic extraction compared to the combined treatment results in a significant extraction of hemicelluloses from the pulp. The viscosity and brightness of pulps (82.04 and 454 ml/g, respectively), on the other hand, increase by the cold caustic extraction. Also, a narrow molar mass distribution can be obtained by this treatment which has much potential for targeted production of cellulose. Overall, the results of this study indicate the success of the conversion of paper-grade pulp to dissolving pulp with a cold alkaline treatment.

Fagus orientalis is a valuable deciduous tree species mainly distributed in northern of Iran.There is great demand in the market for its log especially for knot-free logs. The classification of roundwood is inextricably linked to the measurement of a particular single wood defect. The appearance, location, and number of defects are important in the quality evaluation of logs and sawn timber, and the most important defects are knots. To evaluate the defects of trees, destructive methods (cutting) and non-destructive methods (CT scans) are used. The purpose of this study was to calculate clear wood by four models and compared to CT- scan. Fifteen stems of oriental beech trees were studied. The Pearson correlation coefficient and the Kolmogorov-Smirnov test have been used to check the normality of the data and the correlation between the parameters. The results show that the detection of CT- scan is high at the organs have a significant difference in the density. The accuracy of detection and evalution is high in the CT-Scan method. The results show that there is a high correlation between all methods of estimating clear wood. The most correlation coefficient was obtained between the fourth model and CT-Scan method(r=0.994) which their clear wood estimation are the same. Among the studied models, the first model (∆r=Ws-Ls) which is based on the external indicator is more suitable for evaluating of the beech clear wood in the log grading process

Securities such as banknotes are permanently in contact with the human body according to their type of use and they are handed out daily among different people. This method of application makes these papers extremely contaminated and increases the possibility of transmission of pathogens by them. Therefore, the creation of self-cleaning properties in these types of papers is necessary. Titanium dioxide is one of the most widely used materials in papermaking that nowadays, its nanometer dimensions are considered as a photocatalyst. In this study, direct attachment of titanium dioxide nanoparticles to cellulosic fibers by controlled hydrolysis TiCl4 with urea in the presence of cellulose fibers was used which the homogenization of the suspension was done by ultrasonic waves. The cellulose fibers used were linter cotton fiber. The results of antibacterial and photocatalytic tests showed a very good performance against gram-positive and gram-positive bacteria and methylene blue degradation, respectively, but the results of mechanical and optical tests of the papers were undesirable and limit the use of these particles without applying any modifying method.

The objective of this study was to prepare and evaluate the features of starch films containing cellulose nanofibres (CNF) and lignocellulose nanofibres (LCNF) derived from old corrugated container (OCC) by mechanical method and using super disk grinding to achieve optimal strength, solubility and biodegradability features for food packaging. The characteristics of CNF and LCNF including morphological features (diameter and its distribution) were investigated using field emission scanning electron microscopy (FE-SEM). The studied films based on starch content of 5, 10 and 15% of CNF and LCNF as reinforcement agent were prepared using solution casting method. The effects of CNF and LCNF on physical and mechanical properties, weak acid and alkali, as well as biodegradation of films under aerobic conditions (using soil) were investigated. The result showed that average diameter of LCNF and CNF obtained was 69±10 µm and 28±10 nm, respectively. The results of physical and barrier properties showed that increasing the percentage of CNF and LCNF reduced the oil absorbing. By increasing the percentage of CNF, the solubility in water, acid, and alkali films decreases slightly, but this trend was reversed for LCNF. The results of mechanical strength showed that the increase in the contribution of CNF improved strengths to burst and tear index in the films, but the improvement for the film containing LCNF was less than that of CNF film. The biodegradation process of starch film samples increased by increasing the percentage of CNF and LCNF by 20-15%. It can be concluded that the use of CNF and LCNF leads to increased mechanical strength and decreased solubility to various solvents (water, acid and alkali). Also, with using CNF and LCNF, the biodegradability features were improved and as a result, it became more practical.

Investigation the potential of cellulosic resources was one of the research priorities of our country from the past. In this study, morphological properties of Ammodendron persicum tree stem was done in 5 different heights. Also main wood polymers (lignin, cellulose, and hemicelluloses) and ash in stem, also gas chromatography–mass spectrometry (GC-MS) analysis of chemical extracted compounds from wood four of stem and woody roots of this species performed. According to measurements average length, fibers diameter, lumen diameter and wall thickness of heart wood was 1041.26, 12.30, 3.37 and 4.37 µm, respectively. About sapwood this numbers are 969.19, 11.71, 2.96 and 4.46 µm. slenderness, flexibility and Runkel ratios of fibers was 84.1, 27.4 and 262.02 for heart wood and 82.4, 25.2 and 302.9 for sapwood. The results indicate that these fibers are very narrow pore diameter and thick cell wall is capable. The amounts of cellulose, hemicellulose, lignin and ash for trunks wood were 38.9, 24.7, 29.8 and 0.88% respectively, and for root, were 41.6, 29.2, 24.7 and 2%, respectively. Overall, 13 compound in the trunk and 11 compound were identified at the root, with varying percentages in the trunk and root wood. The most abundant compounds in the trunk of the Docosane (icosane - Docosane - Tricosane - Tetra- Tricosane-Pentacosane -Hexacosane -Heptacosane). In the root wood, Octadecene compound respectively by 40 % and 16.16 % of total extractives was observed. It can be concluded that the fibers and chemical compositions of the Ammodendron persicum species can be valuable in terms of economic aspects and can be optimized by converting them into high value added products.

In this research, the effect of ammonia chemical vapors on the quality of surface wood species of common species in the furniture industry was evaluated. For this purpose, species of Platanus oriantalis, Fagus orientalis, Quercus castaneifolia, Betula pendula, betulus carpinus, Populus nigra, Morus alba l, Abies alba, and Cupressus arizonica were cut accordance to 5-927 EN standard (15 × 10 × 2 mm) and all samples were then transferred to conditioning room (EMC 12%) for 2 weeks. Then, all samples were stored in the test chamber for 30 days, and then the amount of color changes and roughness were evaluated after 5, 8, 15 and 30 days. The results of colorimetric studies showed that the highest and the lowest color variations were related to Quercus castaneifolia and Populus nigra species, which can be considered as one of the most effective factors in extracting materials. By increasing the storage time of wooden samples in ammonia vapor, color changes increased, but the highest color variation was observed in the first 15 days. Also, after ammonia Fuming, roughness was reduced in samples, with the greatest reduction in roughness observed in species of Quercus castaneifolia, Morus alba l and Platanus oriantalis currant.

In this research, momoethanolamine in the charge of 15% with potassium sulfite in four levels as additive and also potassium sulfite in the charge of 14 % as NaOH with addition of monoethanlolamine in four levels were used as cooking liquor for pulping of rice straw. The combination of potassium sulfite/potassium hydroxide and sodium sulfite/sodium hydroxide in the ratio of 50/50 and sulfite sodium treatment in the alkalinity of 14 % as NaOH were selected as reference treatments. The results showed that the pulp produced using pure monoethanolamine (15%) has the highest yield and the highest kappa number. By using potassium Sulfite as an additive in MEA pulping, the rejects, yield and kappa number was decreased and the lowest yield and the lowest kappa number was relevant to monoethanolamine(15%) combined with potassium sulfite (40%). In potassium sulfite (14%) pulping with increasing of monoethanolamine concentration as additive, the amount of total yield increased but the kappa number and reject contents decreased. The highest tensile index was relevant to monorthanolamine (15%) combined with potassium sulfite (10%) and the highest burs index belongs to potassium sulfite (14%) / monoethanolamine (20%) treatment. According to the optical properties, it was found that the highest brightness) achieved in potassium sulfite (14%) / monoethanolamine (20%). The highest opacity was relevant to the monoethanolamine 15% treatment. The results of this study showed that monoethanolamine process in combined with potassium sulfite can be performed successfully on rice straw and pulp properties especially mechanical characteristics in combination case are superior to soda and potassium hydroxide processes. Furthermore, utilization of the combined processes for the pulping of rice straw could be provided the possibility of the use of cooking liquor as organic fertilizers, which its recovery seems to be challenging.

In this study, the effect of the addition of citric acid on physical and mechanical properties of particleboard were investigated. The variable in this research were the ratio of citric acid to wood chips (at four levels; 0:100, 10:90, 20:80, 30:70) and urea - formaldehyde resin (in two levels of 5 and 10 percent). The physical and mechanical properties were evaluated according to European standards set of EN. The effect of citric acid treatment on the wood particles was analyzed by FTIR. Fourier transform infrared spectra analysis suggested that the carboxyl groups of citric acid had reacted with the hydroxyl groups of the wood particles to give the boards good physical and mechanical properties. The urea-formaldehyde resin content can be reduced in the particleboard as good function citric acid in improving strengths. On the basis of results of this study can be concluded that particleboard containing urea-formaldehyde resin in the level of 5 percent and citric acid in the level of 20 percent can be used for general purpose board (Type P1) for use in dry conditions. Also, there was usability of urea-formaldehyde resin in the level of 10 percent and citric acid in the level of 20 percent for interior fitments (Type P2) for use in dry conditions.

It is very essential to identify market concentration to organize the government decisions and policies in order to market adjustment. The aim of this study is to identify import market structure of Wood Pulp and Recovered Paper for helping government and implementing effective policies. In this study are applied indices such as Concentration Ratio, Herfindal-Hirschman, Comprehensive Concentration Industrial, Hannah-kay and Hall-Tideman for calculating market structure. The findings show that, degree of competition between Wood Pulp and Recovered Paper exporting countries is low and barriers to entry are high and it can be said this import market structure is an oligopoly market.

The large parts of the southern regions of Iran are covered by wild milkweed plants. The latex and roots of these plants are used in the pharmaceutical industries, but the wooden parts of this plant are left as waste. Since lots of this type of wastes are annually produced; hence, we conduted this study to use lignocellulosic wastes of wild milkweed plants for the manufacturing of wood-plastic composite and then the mechanical properties of the fabricated compositewere studied. To make composite, milkweed flour in three mixing levels of 30, 40 and 50 percent of total composition, maleic anhydride grafted polypropylene as a coupling agent in two mixing levels of 4 and 6% percent of polymer, were used as variable factors. Also, some of the wood was not debarked, and the level of 40%, was made using debarked wood flour.The mechanical properties of fabricated composite including bending strength, bending modulus, tensile strength, tensile modulus and impact strength, were measured.The study results showed that by increasing milkweed flour consumption, the tensile strength of composite was decreased, but the bending strength was improved. In each of the different mixing levels of milkweed flour (30, 40 and 50 percent), the flexural modulus and tensile modulus of composites increased by increasing the amount of coupling agent (from 4 to 6%).On the other hand, the impact resistance of composites decreased by increasing the amount of lignocellulosic flour in each of the coupling agent mixing levels. Also, the presence of the skin did not adversely affect the mechanical properties of the composite, and it is possible to use this type of wood without the need of debarking.

The article is based on acknowledgment of the importance of the intra industry trade debate for each country, as well as the lack of comprehensive and integrated information on the issue of wood and wood products industry. This article contains two parts: The first part of the calculations is annual for the total wood and wood products industry during the period of 1391-1371 and the second part of the calculations for the year 1395 is broken down by tariff code for wood and wood products. The Grobel and Loyd and the Quality Index have been used to estimate intra-industry trade and determining its type. The results showed that Iran's exports and imports with countries such as Kuwait, Lebanon, Georgia, the Republic of Syria, Azerbaijan, Armenia, Hungary and Pakistan, respectively, with the amount of intra-industry trade 0/44, 0/44, 0/41, 0/39, 0/35, 0/28, 0/27 and 0/25 had the highest average intra-industry trade. Pakistan and Lebanon's industry trade is more of a high quality vertical type. Also, the results of in-industry trade on the basis of each tariff code in 1395 showed that intra-industry trade for 45, 46 (Except United Arab Emirates) and 47 codes were practically zero or zero. While there were countries that have in-industry trade more than zero for codes 44, 48, 49 and 94. Intra-industry trade for the Netherlands, Italy, the United Kingdom, the United Arab Emirates and Kazakhstan in code 44, United Arab Emirates in code 46, Hong Kong, United Arab Emirates, Oman and Malaysia in code 48, Italy and the Russian Federation in code 49 is more Vertical Intra Industry type. . Intra-industry trade for code 94 just for Kuwait is more Horizontal Industry Trade type.

The aim of this study is to investigate the properties of pulp produced by the admixture of wood and non-wood fibers. The mixture of hardwoods chemical-mechanical pulp (60% hornbeam, 20% beech and 20% poplar) of Mazandaran factory with bagasse industrial pulp of Pars factory (non-wood fibers) with ratios of 65 to 20, 55 to 30, 45 to 40, 35 to 50, 15 to 70, respectively were used. Every mixture of pulps was reinforced with 15 percent of the imported long fiber bleached softwood kraft pulp. Pulp properties such as fiber length, ash percent and freeness were determined. Hand-sheets were made and the properties such as brightness, porosity, tensile and burst indices, breaking length, and tear index were measured. The results of the length distribution of fibers showed that the CMP of Mazandaran wood and paper factory has a better quality than the bagasse chemical pulp of Pars Company. The statistical analysis of the results showed that the properties of hand-sheets such as burst index, tear index and brightness decrease with increasing the amount of bagasse pulp, except for the tensile index, which has not changed significantly. Also, with increasing the amount of bagasse pulp, the porosity property was decreased.

Polyhydroxybutyrate-co-valerate (PHBV) is a biodegradable and thermoplastic biopolymer which can be produced by a species of bacteria. This biopolymer has remarkably been noticed by scientific and industrial associations due to the similar properties with polypropylene. In spite of great benefits than petrochemical polymers, the use of PHBV to high-cost production process and also low range of physical and mechanical properties is limited. One solution to overcome this problem is to utilize nanoparticles as reinforcement. In this research, PHBV nanocomposite films containing cellulose nano crystals (CNC) has been provided. The effects of adding nanoparticles on the mechanical properties such as tensile strength and elongation, dynamic-mechanical properties such as modulus and tan δ were studied. Also, morphology and thermal features by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) were investigated, respectively. For this purpose, CNC with ratio of 0, 1, 3 and 5 wt% were added to biopolymer matrix, then nanocomposite films were obtained by solvent casting method. After adding nanoparticles, the tensile strength and thermal stability of the PHBV/CNC composite films increased and the elongation decreased. SEM observations showed that existence of large amount of nanoparticles (3 wt%) are strongly agglomerated in the biopolymer matrix. This leads to decrease of mechanical properties of the composites for more than 3% by weight. Finally, the results of this study showed that CNC is an effective reinforcing agent for modifying physical and mechanical properties of biopolymer composite films.