مجله صنایع چوب و کاغذ ایران
سال هفتم شماره 1 (بهار 1395)

In this study, the effect of nanoclay particles content on creep behavior of wood flour/polypropylene composite was investigated. To meet this objective, wood flour was mixed with polypropylene at 60 % by weight fiber loading. The concentration was varied as 0, 3 and 5 per hundred compounds (phc) for nanoclay. The amount of coupling agent (PP-g-MA) was fixed at 2 phc for all formulations. The samples were made by melt compounding and injection molding. Firstly, the modulus of elasticity, flexural and tensile strength of composites was measured before performing the creep test. Then, the short term flexural and tensile creep test at 20% of ultimate bending load at 12 min was performed. The morphology of the nanocomposites has been examined by using x-ray diffraction and transmission electron microscopy. Results indicated that the creep deflection, relative creep and creep factor increases with increase of nanoclay up to 3 phc and then decreases with 5 phc nanoclay addition. Also, the effect of nanoclay was positive in terms of enhancing the mechanical properties of the composites. The morphological studies with XRD and TEM revealed that nanoclay distributed as intercalation structure in polymer matrix.

Ready to assemble furniture industry in Iran has not been considered by practitioners and investors as it is known in the other countries. While, it is possible to achive the many competitive advantage, if this industry develop in Iran. With regard to this issue, the goal of this study is to introduce the potential market for ready to assemble furniture and determination and prioritize of the effective criteria on development of Iran ready to assemble furniture industry. For this purpose, after preliminary investigation and interview with some of the furniture producers and relevant experts, the identified criteria were divided into five major groups as Economic, Management, Marketing & Sales, Technical-Technological and Infrastructure and as well as 42 sub-criteria. The hierarchy of these criteria was designed and then the weighting values of criteria and sub-criteria were determined using Analytical Hierarchy Process (AHP) by expert choice software. The results indicated that the management and marketing & sales criteria have the highest weighting values at the first level. In addition, among the effective sub-criteria, the criteria as marketing innovation, design innovation, operations management, logistics management, raw materials innovation and product promotion, have the highest priorities for development of ready to assemble furniture industry in Iran.

In this study the effects of oxidative bleaching and mechanical dispersion in different conditions on the optical and mechanical properties of deinked recycled pulp was investigated. Industrial deinked pulp was treated in the different conditions, including dispersion, combined oxidative bleaching during dispersion, and separate dispersion and then oxidative bleaching. Handsheet papers were made from obtained pulps and then scanned and taken photos were analyzed by Digimizer software, version 4.1.1.0 to analysis spot content. Optical and mechanical properties of obtained handsheets were determined and compared. Results indicated that mechanical dispersion decreased spot content and brightness and increased yellowing of the handsheets. Moreover, mechanical dispersion increased dry and wet tensile and burst strengths, water retention value (WRV), ash content and decreased tear strength of handsheet papers. This study revealed that combined dispersing and oxidative bleaching of de-inked pulp provided superior results in comparison to the separate dispersing and oxidative bleaching.

In this research, physical, biometrical and chemical properties of Prosopis juliflora wood and then physical and mechanical properties of kraft pulp from aforesaid species were investigated and calculated. Dry and critical densities of Prosopis juliflora are 0.806 and 0.696 g/〖cm〗^3 respectively. Fiber length 895µm and cellulose 48.80%, lignin 23.66%, extractions 3.88%, ash 1.1% were measured.
The preparation conditions of kraft pulp were included: effective alkaline 14, 16 and 18%, cooking time 120 and 180 min., temperature of cooking 170 and 180 ˚C and L/W ratio 5 to 1. After calculating the amounts of yield and kappa number of pulps, two treatments were determined. The freeness of two pulps was achieved approximately 400 (CSF) by refining. Then, physical and mechanical properties of the handsheets were calculated. Finally, statistical analysis of pulp and handsets data were performed by completely randomized factorial, duncan and T-test methods.
The results showed that the handsheets resulted from produced kraft pulp under conditions: effective alkaline 18%, cooking time 120 min, cooking temperature 180 ˚C, had better mechanical properties. The investigation results showed that Prosopis juliflora of south zone of the country has suitable properties for kraft pulp preparation in comparison to other similar hard wood species and development of its planting, was recommended in the zone.

The aim of this study was investigation of hydration behavior and mechanical properties of cement-bonded particleboard manufactured from different ratio of cotton stalk to poplar wood particle, sawdust content and CaCl2 as additive at different weight ratios. At the first, curing time of cement paste containing different amount of additive (CaCl2) and wood and cotton fines was determined. Besides, the effect of additive (CaCl2) content, weight ratio of cotton to poplar wood particles and percentage of sawdust on modulus of rupture (MOR), modulus of elasticity (MOE) and internal bonding (IB) of cement-bonded particleboard was evaluated by response surface methodology (RSM). In order to optimize the properties of panels, a mathematical model equation (second order plan) was done by a computer simulation program. According to results, there is a good coincidence between predicted values and actual values (R2 for MOR, MOE and IB was 0.93, 0.90 and 0.95, respectively). This study showed that the response surface methodology (RSM) can be effectively used for modeling of panel properties. Results showed that using weight ratio of cotton to poplar particle 43:57 the MOR, MOE and IB of panels can be reached to maximum values (12.5, 2545 and 0.35 MPa, respectively). Simultaneously, application of 4.5% additive and 9% sawdust at had a positive effect on the properties of the panels.

This study aimed at evaluating effect of sizing agent and various fillers on properties of printing and writing paper. Therefore, sizing agent (AKD) in 1.5% level and fillers including precipitated calcium carbonate (PCC), ground calcium carbonate (GCC) and Obtained from Water Treatment Process (SCC)in 30% level were applied based on dry weight of fibers in furnish consisted of 80% chemical-mechanical pulp (CMP) of hardwood and 20% bleach softwood kraft pulp (BSKP) according to TAPPI Standard. In order to investigate the effect of sizing agent and various fillers, papers with 60 g/m2 basis weight were produced from each treatment. Results showed that the dimensional properties of calcium carbonate species is effective on strength properties of paper. Of the three types of ground calcium carbonate (GCC), precipitated (PCC) and softening calcium carbonate (SCC), precipitated calcium carbonate due to smaller particles cause a further reduction in paper strength and Calcium carbonate from water softening due to the larger particles, had a minimal impact in reducing the paper strength properties. Paper filled with precipitated calcium carbonate has an intermediate strength properties of paper filled with precipitated calcium carbonate and softening calcium carbonate.

The major engineering properties of Acer velutinum var. glabrescens wood growing in different regions of Caspian forests (North of Iran) was determined. Test materials were selected randomly from Acer velutinum var. glabrescens tree plantation and the test specimens were prepared according to ASTM D-143 standard. Mechanical and physical properties were measured on both green and air-dried samples (12% moisture content). The results of the measurement were statistically analyzed based on randomized block design and factorial experiment. The influence of specimen locations at different stem heights was examined. Based on the results of this study, Significant areas of habitat in the area, Maple Vysr Mazandaran species most resistant of the Maple Sangdeh Frame has the lowest resistance.

The objective of this work was to compare barrier property of biodegradable coatings on two base papers. Two different paper grades differing in structure (Kraft liner and printing & writing papers) were used. The papers are made in Mazandaran wood and paper industry. Coating materials with 30% solid content, included clay (100 parts) and cationic starch (12 parts), and they were mixed with two binders (PLA 10 parts and PVA 10 parts) for two formulations. The immersion method in both levels 1 and 2 minutes and two coating formulations were applied on papers. Then, the treated samples were dried in standard conditions of temperature (25◦C) and 54% humidity in the room. For that purpose, air resistance or porosity, thickness, mass, and Cobb60 were determined. As expected, time of treatment, reduced porosity and increased coating weight, but in terms of barrier properties, combination containing PVA was more effective than PLA. In comparison to the control group, all the treated samples had higher air resistance and water absorption, which the increment of water absorption is due to increased capillary in texture paper. The analysis of results showed that the immersion coating factors had considerable effects on performance of air resistance improvement and coating weight of papers. Then, calculated values of the thickness and density of coating were evaluated, which confirmed the status of water absorption. The treatments greatly increased the wettability of the surface by water.

This work aims to evaluate the thermal and dynamic mechanical properties of bagasse/glass fiber/polypropylene hybrid composites. Composites were prepared by the melt compounding method and their properties were characterized by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). DSC results found that with incorporation of bagasse and glass fiber the melting temperature (Tm) and the crystallisation temperature (Tc) shift to higher temperatures and the degree of crystallinity (Xc) increase. These findings suggest that the fibers played the role of a nucleating agent in composites. Dynamic mechanical analysis indicated that by the incorporation of bagasse and glass fiber into polypropylene, the storage modulus ( ) and the loss modulus ( ) increase whereas the mechanical loss factor (tanδ) decrease. To assess the effect of reinforcement with increasing temperature, the effectiveness coefficient C was calculated at different temperature ranges and revealed that, at the elevated temperatures, improvement of mechanical properties due to the presence of fibers was more noticeable. The fiber-matrix adhesion efficiency determined by calculating of adhesion factor A in terms of the relative damping of the composite (tan δc) and the polymer (tan δp)and volume fraction of the fibers (Фf). Calculated adhesion factor A values indicated that by adding glass fiber to bagasse/polypropylene system, the fiber-matrix adhesion improve. Hybrid composite containing 25% bagasse and 15% glass fiber showed better fiber-matrix adhesion.

The objective of this study was to determine the influence of Furfurylation treatment on adhesion strength of clear coatings and surface roughness of Beech (Fagus orientalis) wood. Furfurylation of specimens were performed by impregnation and heat catalyze up to 20% and 65% weight percent gain. Half of the specimens coated with acid catalyst paint and half of them coated with polyurethane based paint. Surface roughness and adhesion strength (Pull-off) and cross-hatch cutter test were analysed and compared to untreated specimens. Results revealed that 20% furfurylated specimens did not show significant difference in roughness and adhesion strength, compared to untreated control. But 65% furfurylated specimens caused decline in adhesion strength and raise in surface roughness. Polyurethane based paint had better efficiency and adhesion strength than acid catalyst paint. The highest adhesion strength observed in 20% furfurylated specimens coated with polyurethane and the least obtained in 65% furfurylated wood coated with acid catalyst paint.

In this study, the liquorice root (Glycyrrhiza glabra) that was extracted in the factory in Kerman province, pre-hydrolyzed and then chemical compositions (Extractives, Lignin content, Holocellulose percent), the hydrolysis process yield and weight loss of the waste was measured. Pre-hydrolysis process was done on the above mentioned waste by hot water, hot water followed by 0.5 percent sulfuric acid and also alone sulfuric acid with different concentrations (0.5, 1, 1.5 and 2 percent) The samples were pre-hydrolyzed in hot water at 150 °C and 30, 60 and 90 minutes as well as in the mixture of hot water and 0.5 % sulfuric acid at 150 °C and 60 minutes and also in pure sulfuric acid, at 130 °C and at 60 minutes. The results showed that the pre-hydrolyzed treatment with hot water in 60 minutes had been favorable performance in the respect of weight loss, lignin content and holocellulose percent. Also, in the case of pre-treatment including sulfuric acid, 2% dose can be good selected option in term of maximum holocellulose percent and minimum lignin content so that it can be suggested to produce higher value-added products such as bioethanol from licorice root bid.

Value added in the poplar wood value chain has great economic effects for poplar farmers and have a fundamental role in sustainable supplying of required cellulosic materials of industries in long-term. The purpose of this study was to analyze the value chain of poplar and use the results to improve it. In order to determine the poplar value chain, Porter's value chain analysis framework was used. The statistical society consists of 76 experts to identify poplar wood value who were active in different parts of the value chain. Value chain analysis was performed using the location quotient index. With this method the local economic conditions of poplar wood value chain were evaluated to the global economic conditions poplar wood value chain in the country. With the help of experts and using a questionnaire, important industries that use poplar wood as a raw material were determined. The maximum poplar value chain location quotient index was blong to Golestan (2.72) and the minimum poplar value chain location quotient index was blong to Hormozgan (0.24). The Northern provinces (Golestan, Guilan and Mazandaran) had the highest location quotient index. The location quotient index of the poplar wood value chain of Golestan, Guilan and Mazandaran were 2.72, 2.19 and 2.03, respectively. The location quotient index of poplar wood in Zanjan, West Azerbaijan, East Azerbaijan and Kurdistan that they are major manufacturers of poplar wood, were 0.36, 0.47 0.65 and 0.84, respectively.