مجله تحقیقات علوم چوب و کاغذ ایران
سال سی و سوم شماره 2 (پیاپی 63، تابستان 1397)

The application of corn stalks in the production of oriented strand board (OSB) is investigated. Corn stalks strands were produced in three sizes of 50, 75 and 100 millimeters length and dried to reach 2% moisture content. Oriented strand boards were made using either urea formaldehyde, melamine formaldehyde and phenol formaldehyde resin, and two press temperatures of 175 and 185 ° C. OSB boards using poplar wood strands, 100 millimeters long were also produced as control samples. The results of strength measurements of the boards were statistically analyzed using factorial experiment and completely randomized block design. The grouping of the averages was based on Duncan Multiple Range Test. The results showed that the effect of the resin type on the flexural properties and internal bonding of the boards is statistically significant and boards produced using phenol formaldehyde resin exhibited the lowest modulus of rupture, modulus of elasticity and internal bonding strength. However, the adhesive type did not statistically influence the physical properties. The strand length also statistically influenced the board strength properties and boards made using poplar strands showed higher strength compared to corn stalks strands. The thickness swelling of the poplar OSB was almost twice the values of corn stalks OSB but the water absorption of these boards was lower than of corn stalks OSB. Press temperature adversely affected the modulus of rupture and elasticity, but higher press temperature improved the internal bonding strength. Higher press temperature increased the physical properties of the boards.

The main objective of the current study was the investigation of the effect of adding the wollastonite nanoparticles (casio3) to the water based acrylic coating onto the fire resistance capability and adhesion strength of coating. The nano wollastonites with the concentrations of 0.5, 1.50, and 2.5 wt% were dispersed into the coating. Ultrasonic device was used to stabilize the nanoparticles into the substrates. The coating process was carried out with and without application of the nanoparticles on the surfaces of spruce and sycamore samples and their properties comprising the fire resistance and the adhesion strength were investigated. The obtained results showed that adding of nano wollastonite to the acrylic coating with the waight percent of 2.5% (w/w) had the significance effect onto the resistance of the samples to fire. In particluar, these effects was observed in cas of the retard time of ignition of the spruce and sycamore samples with the improvement values of 258 and 184 % compared with the control samples, respectively. Furthermore, the investigation of adhesion properties of coatings to the sample surface indicated that the applied nano wollastonites improved these properties of coatings. In case of the adhesion properties, however, the highest value of this properties was observed in the highest content of wollastonite nanoparticles. It should be noted that the performance of nanocomposite coating containing of the 1.5 wt% of nano onto investigated properties was also acceptable.

Nowadays, Due to the unstable world economy, to survive and create competitiveness in domestic and overseas market, sustainable production and increases in quality and quantity of products is needed, In case of no attention, the possibility of competitiveness in regional and international markets will not occur. Therefore, in this study, with cooperation of experts and industry manufacturers’ expertise determination and ranking of factors affecting classic furniture was determined by using analytical network process and DEAMATEL techniques. 5 main and 17 sub-indexes parameters examined in this study and by using analytical network process the importance of prioritizing criteria was determined and cause and effect relationships between indicators was evaluated by DEAMATEL techniques. The results showed that, the main indicator of production and sales management, quality assurance, design style and creativity have the highest normal weight and the sub-indices of the modernity of machines and technology, reasonable price and Brand longevity respectively, are the three top priorities to impact on the competitiveness of classic furniture.

Current research was conducted to investigate the effect of nano Alumina modification on the mechanical and Surface properties of High-Density Fiberboard (HDF) made from oxidized fibers. Surface activation of fiber was done with 40% nitric acid. After fibers gluing with urea-formaldehyde (7% and 9% based on the dry weight of fibers), the boards were made by hot pressing. For veneering, two types of paper with grammage of 70 and 80 g/m2 impregnated with melamine-formaldehyde and nano-alumina 0, 1.5 and 3% were applied. According to the results, the highest bending strength, modulus of elasticity and hardness were measured in nitric acid-modified fibers/ 9% glue/ grammage of 80 g/m2/3% nano-alumina samples that was significant increase compared to the control boards a significant increase. The samples weight loss due to abrasion was decreased with increasing the veneers grammage and nano-alumina, which confirmed the positive effect of nano-alumina. Veneer grammage did not show significant effect on the resistance to cigarette burn, but the highest concentration of nano-alumina resulted to improve this surface resistance via increase of thermal conductivity.

The objective of this study was the evaluation of optical, mechanical properties of chemi-mechanical pulp which were bleached by one and two stage bleaching sequence of hydrogen peroxide and sodium hypochlorite. Also the environmental effects of effluents from bleached paper liquor were studied. For this purpose, unbleached CMP pulp mixed of hardwoods was prepared from Mazandaran Wood and Paper mill. Then, these pulps were bleached using P (hydrogen peroxide), H (Sodium Hypochlorite), PH (Hydrogen Peroxide and Sodium Hypochlorite) and HP (Sodium Hypochlorite and hydrogen peroxide) stages. 60 gr/m2 hand sheets were prepared and the optical, mechanical properties of hand sheets and also their effluent bleaching liquor characteristics were measured and analyzed based on TAPPI and APHA Standards. The results showed that when peroxide was applied at the last stage of bleaching, then the properties such as tear, tensile and brightness have increased and yellowness has decreased. Generally, the role of single sequence of bleaching by P and two sequence of bleaching with HP were more effective than single sequence of H or unbleached pulp. Based on results, the highest and lowest COD load is related to bleaching liquor of H and PH respectively. Moreover, bleaching liquor of hydrogen peroxide had the highest BOD load and the lowest amount of BOD is related to PH sequence of bleaching.

In this study, the tensile and dynamic-mechanical properties of composites made by poly-lactic acid polymer (PLA) and high density polyethylene (HDPE) as matrix and sawdust to reinforcement 30 % weight were investigated. Maleic anhydride bonded with polyethylene (MAPE) was used to increase coupling agent by 3%. The use of sawdust increased the stiffness of composites while the use of this material reduced the tensile strength of composites. The highest tensile properties (elastic modulus and tensile strength) were related to poly lactic acid /polyethylene / sawdust / coupling agent composites. The addition of natural fibers to both matrices (PLA and MAPE) increased the composite storage modulus compared to pure polymers, while the modulus of storage in pure polyethylene and its composite was higher. Simultaneous use of two polymers with an equal ratio (33.5% by weight) and composite sawdust have shown the stiffness between the composites made with single polymers. The use of natural fibers reduced the mobility of the molecular chain and transported the temperature of the composite to higher temperatures, which eventually moved the corresponding corners to the right and lower. However, in some cases, the transmission of pixels has not followed the normal process. The addition of the coupling agent (MAPE) makes bonding more common between two phases in all composites and ultimately increases stiffness.

Cellulosic fines are essential parts of paper making system which impart remarkable effects on the production process parameters and the quality of final product. In this study, properties of fiberfines prepared from three kinds of pulps including Kraft, chemical mechanical (CMP), and recycled (OCC) were investigated. Required amounts of fines were prepared using Valley Beater apparatus. Then the fines were classified into three categories using dynamic drainage Jar (DDJ): fines passing a 100 mesh remained on 200 mesh (P100/R200), fines passing a 200 mesh remained on a 325 mesh (P200/R325), and fines passing a 325 mesh (P325). Fines properties including dimensional size, special hydrodynamic volume, colloidal charge, alkalinity, turbidity, viscosity, and specific area were examined. The results revealed that PH of fiber suspensions tended alkaline concurrently to the decreasing in dimensional size of fines. Additionally, the colloidal charge of the three types of fines, especially the charge associated with the fines passed through 200 mesh screen and remained on 325 mesh one, showed a different behaviour compared to those in the same classes with the adverse trend to the viscosity variation. Special hydrodynamic volume is consistent with the dimensional size and dimensional ratio with the lowest amount of it observed in the recycled pulp fines. Turbidity has a direct relationship with particles size, homogenous distribution and the specific area of the finesThe results of turbidity related to the fines passed through 200 mesh size showed different behaviour compared to other categories.

Chemical and biological treatment of dye- containing wastewaters is difficult due to the low adsorption level and chemical stability of dyes. Activated carbon is usually used for adsorption of these materials, but because of high prices and restore problems, researchers trying to find available low-cost materials with high adsorption. In this study, bagasse was used for adsorption of Acid Grange7 dye and its capability was examined. Variables were concentration, temperature, pH and contact time, and the degree of adsorption was examined in different situations. Then, adsorption isotherm according to Langmuir and Freundlich models was investigated. The results showed that the adsorption efficiency depends more on pH of solution and less on temperature of the solution. Maximum adsorption of Acid Orange7 dye by bagasse occurred in the first 15 minutes of contact. The study of adsorption isotherm showed that both models are suitable for description of adsorption of Acid Orange7 dye by bagasse. Maximum adsorption of Acid Orange7 dye by bagasse was calculated as 18.56 mg/g. Results of this study showed that bagasse could be used as a low-cost bio adsorbent for the adsorption of Acid Orange7 from aqueous solution.

Stickies is among the major challenges in paper recycling mills. This substance deposits on paper machine components and cause to break paper web as well as loss of end product quality. So, it is necessary to control the stickies and lessen its detrimental effects. It is known that cationic polymers as fixing agents can control the stickies efficiently. Therefore, the control of stickies of OCC pulp using a commercial cationic polymer called GL at 0.4, 0.8 and 1.2 percent based on oven dry weight of pulp at pH 4 and pH 5 were investigated. Macro- and microstickies, dissolved and colloid substances (DCS), turbidity, and drainage time were measured to evaluate GL efficiency and compared with control sample. The results indicated that GL dosing at 0.4 and 0.8 percent in pH 4 and 7 due to flocculation and fixing the stickies onto the fiber caused to decrease in macro stickies, microstickies and DCS while improved the drainage time. Although, no efficient performance was observed in controlling stickies at higher content of GL i.e. 1.2 percent. Generally, it is concluded that with consuming at desired pH and dosage content, GL can be used as efficient agent to control stickies in processing of OCC pulp.

With growth and development of the modern societies and achieve towards industrialization of the countries, Use of the water, one of the major concerns is considered. Optimal usage of water resources, has special position and considerable, that its result is importance of the reuse of rain's water as a reliable source for supply the consumption water. The purpose of this research was, use of rain's water, in composition with urea formaldehyde adhesive, In order to adjust the final concentration of the adhesive. To prevent damage against rain water equipment, the Lagan system was transferred through the canals constructed at Arian sina factory. Then it was treated with the package at the factory. The results of the FT_IR spectrum, obtained from composition adhesive samples with rain's water and ordinary water, showed that the rain's water increased the number of hydrogen bonds in the adhesive. But based on the t test, the difference between Mechanical strength and physical properties of use of rain's water than to the ordinary water was not significant. Qua that the glue combined with rain's water does not have any negative effect on adhesive properties. Therefore, after research, Arian Sina has been saving water consumption by using 14000 liters of water per day, due to the country's limited resources and lack of resources.

Dyes release into waste water due to its toxicity for some organisms results in major environmental pollution problems. The activated carbon (AC) is an efficient adsorbent to remove this kind of pollutants from aqueous phase. Hence, in this research activated carbon was prepared from sound and rotted beech wood by chemical activation method and its adsorption capacity for removal of Rhodamine B was assessed. The carbonization and activation steps were performed at single stage with impregnating the substrate by zinc chloride as activating agent and with the ratio of 75, 100 and 125 percent to raw material mass at 400 and 500 ºC. The results showed that with increasing the impregnating agent content, the iodine number of ACs from both woods enhanced. The yield of AC from sound wood decreased with increasing impregnating agent while it was not predictable for AC resulted from rotted wood. Scanning electron microscopic (SEM) studies revealed much morphological changes in the surface of rotted wood-AC in comparison with sound wood -AC after treatment with activating agent. Also, raising the activating temperature from 400 to 500 ºC caused to enhance the iodine number. All prepared ACs performed much efficient in removal of Rhodamine B from aqueous solution. The maximum adsorption of the dye was obtained for ACs prepared under impregnating ratio of 125 and activating temperature of 500 ºC.

One of the drawbacks of utilizing non-forest fast growing species of Poplar as raw materials to produce newsprint in Mazandran Pulp and Paper Mill is fairly low bulk and opacity of produced paper at the yield of 85% (current CMP yield of the Mill). In this research work, the effect of process parameters (cooking yield and freeness) on the optical and mechanical properties of chemi-mechanical pulp was investigated. The chemi-mechanical pulps of poplar was prepared at four various levels of cooking yield, through changing the cooking time, and their properties at different level of freeness were evaluated in comparison with the control sample of Mazandran Pulp and Paper Mill (75% hornbeam and 25% beech). Strength properties of the paper pulps stemmed from the cooking yields of 85.25% to 90.4% were higher and more favorable than the control sample. By contrast, the strength properties of the produced paper pulp from the cooking yield of 94.6% were inferior to prepared paper pulp from the control sample. According to the results, there is the possibility of significant improvement of the strength properties, opacity and bulk of the chemi-mechanical pulps of poplar trough controlling the process parameters like cooking yield and freeness to utilize it as raw material of newsprint production in Mazandran Pulp and Paper Mill.

This study was focused on the preparation of an environmentally friendly nanocellulose based hydrogel in the form of pads. Hydrogels are hydrophilic three dimensional network with crosslinks, swells in water but don’t dissolve. In this research nanofibrillated cellulose and Hydroxyethyl cellulose with different ratio (1:1, 2:1, 3:1) were used to make hydrogel. Also, citric acid which has a significant advantage over other crosslinking agents in terms of toxicity and price, has been used in different amounts of 10% and 20% by weight to crosslink. In order to find optimal hydrogel preparation conditions, FTIR analysis, FESEM, time dependent swelling measurement and evaluating the thermal and rheological properties were performed. Samples with a lower ratio of nanocellulose to hydroxyethyl cellulose were found to be inappropriate due to the loss of their apparent integrity in the swelling measurement. According to FTIR results, cross-linking were performed only in samples with the highest ratio of nanocellulose to hydroxyethyl cellulose in different amounts of citric acid. Therefore, the hydrogel's characteristics were mainly influenced by the ratio of nanocellulose to hydroxyethyl cellulose and the amount of citric acid had less effect on these properties. These two successful final samples showed acceptable properties in other evaluated properties and led to the selection of optimal reactive ratios for the preparation of hydrogels for use in various industries, including the pharmaceutical industry.