Iranian Journal of Wood and Paper Science Research
Year:2011 | Volume:26 | Issue:2 (35)|Papers Count:17

In this work effect of initial alkali charge were investigated on the yield and kappa number of soda beech pulp and alkali consumption pattern. The results indicated that, the regression models are useful for studying the relations between yield, kappa number and alkali consumption. Soda cooking was performed in 30, 40, 50, 60 and 70 gr.lit-1 initial alkali concentration and five different cooking times. The chips dimensions were in the range of 3-5 cm length, 1-2 cm width and 0.05 cm thickness. The results showed that increasing of alkali charge decreased the time of cooking in the same yield or kappa number. Deligninifaction decreased significantly in kappa number lower than 30. In the same kappa number, increased alkali charge gave a lower yield. The alkali consumption was regularly decreased with increasing of initial alkali charge from 30 to 70 gr/lit, but alkali charge consumption pattern varied in less and more than 30 kappa numbers.

The influence of oxygen delignification as an environmental friendly process, was investigated on Soda/AQ pulp from Old Corrugated Container (OCC) fibers. Oxygen delignification at four levels of alkali (2, 3, 4 and 6% based on OD weight of pulp) has been applied and the optimum alkalinity to reach optimum Kappa no, yield and brightness, opacity and strength based on 60 g/m2 hand sheets were determined. The results indicated that application of oxygen delignification marginally reduced the opacity of the pulp. Tear strength increased where as tensile and burst strength decreased. Based on the comparison of the data from oxygen delignified pulp, it is concluded that oxygen can be utilized to improve the properties of soda-AQ pulp from OCC prepared for bleaching step. Carbohydrates are preserved while removing lignin. Normalized equations revealed that oxygen delignification at 3% alkali produced the best results.

In this study, deinking of waste newspaper was investigated by conventional and enzymatic methods. Conventional deinking was done in pulping times of 10, 20 and 30 minutes along with different processes of washing, flotation and combined washing/ flotation. Enzymatic deinking was accomplished at different charges of 0.025, 0.05, 0.1 and 0.2% cellulase enzyme (based on oven-dried waste paper), pulping times of 10, 15 and 20 minutes, pH range of 5-5.5 along with one-stage washing process. Optimum compositions were selected from chemical and enzymatic treatments and then physical and mechanical properties of the paper produced in optimum conditions were compared. Achieved results from comparison of the physical properties of optimum chemical and enzymatic treatments showed that, the paper produced from deinked pulp by conventional method had higher calliper, bulk and porosity. Using of 0.1% cellulase resulted the papers with higher tensile and breaking length compared to chemical treatments. The papers could be produced with similar burst and tear indexes compared to chemical treatments using of 0.1% cellulose, as well.

Corrugated board is considered as a valuable community for packaging at both international and domestic markets. Therefore for the development of corrugated board industry in Iran and to understand the variation in demand for this product, it's necessary to identify the consumption and production patterns as well as the most important and effective variables influencing it's status. Then the demand & supply for corrugated board can be forecasted. In this study, the dynamic econometric model has been used to demonstrate simultaneous relationship between supply and demand. Coefficients of the model were estimated using 3sls method with the time series data from 1981 to 2007. The results indicated that in the demand function, intercept, price, GNP in previous period, population, CPI, industrial added value (Iav), production index of large-scale industries (PILSI) and the war dummy variables are significant at 0.05 level. In the supply function, intercept, production quantity in previous period, inflation rate, corrugated board price-raw material price ratio in previous period, import quantity in previous period, cost price all in previous period and subsidy dummy variables are significant at 0.05 level. Results indicate that the mentioned variables influence consumption and production, simultaneously. The results of projection also demonstrate that corrugated board production & consumption will increase into 2012.

The possibility waste paper (writing paper and newsprint) and old corrugated carton (OCC) utilization as a filler of urea formaldehyde resin on plywood manufacturing was investigated. The effect of type of filler as a variable factor on applicable properties i.e. water absorption and swelling after 2 and 24 hours, bending strength parallel and perpendicular to grain and shear strength on the interface was evaluated and the results were analyzed. The results of this study showed that utilization of waste paper and old corrugated carton as the filler decreased the water absorption and swelling and improved their mechanical properties. Since this materials caused to promote adhesion and improved the urea formaldehyde resin bond, it can be inferred that waste paper and old carton can act as an extender on the resin binding process.

Characteristics of pulp and paper mill solid wastes depend generally on the raw materials, stock preparation process as well as wastewater treatment plant. In order to determine the best application of paper mill solid wastes, physicochemical properties of solid waste produced in the Mazandaran Wood and Paper Industry Co. and Latif Paper Co. were analyzed. The dry content, pH, fiber dimensions, composition of organic and inorganic compounds of the both solid were analyzed. The dry content of the produced wastes in Latif and Mazandran were determined as 69.3 and 36.7 percent, respectively. The pH of both wastes was close to neutral (pH/7.0). The fiber length of Latif and Mazandaran wastes were 1.68 and 1.08 mm, respectively. In addition, the total amount of carbohydrates, glucose and mannose quantity in the Latif waste were determined as 48.09, 29.5 and 7.2 percent that were higher than that of Mazandaran waste. In the contrary, the lignin, xylose and galactose content of Mazandaran waste were determined as 15.3, 17.3 and 3.7 percent that were higher than those of Latif waste.The mineral content of Latif and Mazandarn wastes were determined 44.7 and 39.5 percent, respectively. XRF analyses revealed that the predominant elements in the incinerated ash of both wastes contained calcium oxide, aluminum oxide and silicon oxide that can be used as raw material for lightweight concrete and zeolite synthesis.

In this study the possibility of bagasse fiber usage in Fiber-Cement Composite (FCC) manufacturing, was investigated. Two load of bagasse fiber (%4, 10), three level of calcium chloride as facilitator (5, 7.5 and 10 percent per dry weight of cement) and two type of Portland cement (type II and V) were considered as variables (12 treatments). There were three replicates for each treatment, thus 36 experimental board were manufactured totally. The physical and mechanical properties of experimental specimens were investigated and results analyzed by SPSS software as fully randomized factorial model. As results indicated, there was no significant different between cement type II and V in physical and mechanical properties. The increased loads of calcium chloride caused a striking reduction in mechanical properties and increased water absorption amounts. The best bending strength, modulus of elasticity, IB and minimum thickness swelling were reported in treatment with 4% fibers, 7.5% calcium chloride and type II cement.

In this research the physical and mechanical properties of 3-layer particleboard manufactured by bagasse and forest wood particles have been studied. The amount of raw material and the type of adhesive were variation factors. First the effect of raw material on physical and mechanical properties has been evaluated in the six treatments.60-40% and 80-40% treatments (bagasse-wood particles), regarding to bending strength, modulus of elasticity, internal bending strength, water absorption and thickness swelling after 2 & 24 hours soaking in water, have been selected as optimum treatments. Then the effect of types of adhesive on optimum treatments has been evaluated. The achieved results show that the particleboards manufactured by isocyanate adhesive have the highest MOE and lowest water absorption and thickness swelling after 2 & 24 hours soaking in water. In this research, according to the results of analysis of variance and the interception effect of raw material and type of adhesive on physical & mechanical properties of particleboards, 80-20% treatment (bagasse-wood particles) with isocyanate adhesive have been selected as preferable treatment.

The main objective of this study was to examine, the use of thermo set epoxy resin and wood powder for making wood polymer composites. Results showed that mechanical properties of wood polymer composites that are manufactured were better than wood specimen. Also the water uptake of samples was measured and the results showed the water absorption of wood polymer composite is too much less than wood sample. Images and infrared spectroscopy analysis support this fact that wood polymer composites are more stable than wood. Then the effects of adding wood powder to fiberglass composites were examined. The Results have clearly shown that adding appropriate amount of wood powder to fiber composites will considerably improve their physical and mechanical properties.

Poplar lumbers with nominal thickness of 5 cm from Taleghan region, located in west of Karaj were dried under three different schedules including T8-F4 (recommended schedule by F.P.L for poplar), T8-F5 and T9-F4. The purpose of this research was to study the effects of the kiln’s rows (upper, middle, lower) on the quality of the dried boards. Dry bulb temperatures for the schedules were adjusted at 54, 54 and 60°C, while the final temperatures were adjusted at 82, 82 and 71°C, respectively. The severity of warping, internal checking and surface checking in kiln dried lumbers were measured and analyzed. The results indicated that the boards in upper, middle and lower rows of the kiln, in all three schedules, did not have any significant difference in 95% confidence interval. Also, the final moisture content of the boards in all three rows and all three schedules were in acceptable quality.

This work investigated effect of height and cultivar on morphological properties of bast and core fiber of tobacco stalk (Nicotiana tabacum). Also, in this research cultivar effect on chemical properties of tobacco stalk were investigated. Selected cultivars include Barley and Virginia, and investigative height positions were chosen 5, 50 and 75% of stalk height. Results indicated that bast fiber length, diameter and wall thickness are more effective than those of core fiber. Chemical analysis of stalk’s parts indicated that cellulose and ash contents of bast were higher than those of core, but lignin content of bast was significantly less than that of core.Also, extractive material of bast was less. Statistic results showed that length and wall thickness of Barley’s bast fiber were higher compare to Virginia, but there was no significant difference in terms of morphological properties of core fibers between these cultivars. Cellulose percentage of Barley cultivar was higher, where as lignin, extractives and ash contents of Barley were lower than that of Virginia cultivar. Also, cultivar type didn’t have significant effect on contents of tobacco stalk parts (bast, core and pith). Results indicated that, fiber length, diameter and wall thickness of bast decreased as height increases, but in core fiber, just fiber length decreased and other properties of core fiber had different behavior. Moreover, bast and pith percentages increased by height increasing while, core percentage decreased. In general, results of this research showed that, tobacco stalk are a suitable row material for pulp and paper production, re fiber dimensions and chemical components.

In this research, beech (fagus orientalis Lipsky) lumbers at 5 cm thickness were ran domically selected and commercially cut down from sari region (Neka choob company), with three schedule namely T5-C3, T5-C4, T6-C4 were adapted for drying the lumbers down to the final moisture content of 8% to evaluation the effect of kiln schedule on warp and surface checking. primary dry bulb temperature each three schedules was adjusted at 49 °C and the final dry bulb temperatures was adjusted at 71, 71 and 82°C respectively. Basic Specific gravity and dry specific gravity were measured 0.52 and 0.61 respectively. Longitudinal, radial, tangential and volumetric shrinkage were measured 0.46 %, 5.8%, 10.2%, 16.46% respectively.Quantity of defect s including crook, bow, twist and three longest surface checks of the lumber were measured before and after the drying process in each stage. In order to analysis the lumber defects for estimating the best schedule, quality control graph were used. In the end, results of investigation indicated that drying of beech lumber by using of the three schedules was desired.However the third schedule (T6-C4) had better drying characteristics than the other schedules.

The impact of chemical treatment variables including treatment time and temperature, chemical charge as well as pulp freeness on fiber quality of Colza stem chemi-mechanical pulp was studied using Fiber Quality Analyzer (FQA). Three treatment times (15, 30 and 45 minutes), two treatment temperatures (125 and 145°C), two chemical charges (4% NaOH+8% Na2SO3 and 8% NaOH+12% Na2SO3) as well as pulp refining were evaluated. The results revealed that at higher values of treatment variables, fiber average length was reduced and varied between 0.49 and 0.65 mm. However, the influence of pulp refining on fiber average length was not very pronounced. Pulps contained between 55-63% fines, which is on the high range and refining increased the fine content by 5%. Fiber coarseness varied between 10 and 41 mg/100m which was raised to 14 and 53 mg/100m upon refining. Even though refining did not alter fiber curl, but fiber kinks were increased.

This study was carried out with the aim of producing fluting paper from wheat straw soda-AQ pulp and OCC pulp blend. Handsheets at 120 gr/m2 basis weight were made by blending the unbleached wheat straw pulp with OCC pulp at ratios of 25, 50 and 75%. Physical and strength properties of these papers were measured and compared to unblended papers. Results indicated that, paper properties were considerably affected by incorporation of the wheat straw pulp. In other words, in case of utilizing wheat straw soda-AQ pulp in OCC pulp, acceptable physical and strength properties can be produced, so that, the incorporated 75% of wheat straw pulp to OCC pulp, the best thickness, air resistance, roughness, tear index, burst index, folding endurance, breaking length, CMT and RCT can be achieved. According to obtained results, unbleached wheat straw soda-AQ pulp can be used not only to enhance the physical and strength properties of fluting paper but also as a lignocellusic source for making fluting paper.

Using high consistency pulp especially in bleaching plant is highly attractive due to considerable reduction in energy and water consumptions and low effluent volume. This research investigates the effect of consistency CMP pulp on bleaching by hydrogen peroxide. For this purpose, unbleached mixed hardwood CMP pulp of Mazandaran wood and paper CO. mill was used. Bleaching was carried out with QP sequences. Pretreatment or Q stage was carried out by DTPA as a chelating agent for removing transition metals. Chelating stage had a similar condition for all pulps. bleaching with hydrogen peroxide was carried out in three levels of hydrogen peroxide 2, 3, 4% and proportion NaOH to H2O2: 0.8, 0.7, 0.6 by adding 3% sodium silicate in 70°C and 150 min at four consistency level (10, 15, 25 and 30%). After bleaching, handsheets were made with grammage 60gr/m2 from bleached pulp. The experimental results showed that high brightness and opacity and lower yellowness was obtained at 30% consistency by 2 and 3% peroxide charge. However, by using 4% hydrogen peroxide, higher brightness and lower yellowness attained at 25% consistency. Brightness is increased continuously by increasing consistency from 10 to 30% at 2, 3% peroxide. But at 4% peroxide charge, brightness is increased from 10, 15 and 25%, and then at 30% consistency is decreased significantly. Also under conditioning of 2% peroxide and 30% consistency and 2% peroxide at 25% consistency can obtain similar brightness to 3% peroxide and 25% consistency and 4% peroxide at 10% consistency. That it means of 25, 30% decrease in consumption peroxide and sodium hydroxide.