Iranian Journal of Wood and Paper Science Research
Year:2016 | Volume:30 | Issue:4|Papers Count:18

This study has been conducted to determine the fiber dimension and chemical composition of grape tree branches cultivated in Astara, Guilan. For this purpose 53 branches, with identical size and diameter were cut from some grape tree and were sent to laboratory of wood and paper industries in Islamic Azad university Astara branch. Inorder to study the morphological characteristics of the fibers, samples from the branches were selected at 3 the heights of 5%, 50% and 75%. Fiber separation was done using the method developed by Franklin (1954) and then dimensions of fibers and their biometric coefficients were determined. Wood flour was prepared from the branches with bark and without skin and then, the percentage of chemical components was determined according to TAPPI standard test methods. The overall average percentage of holocellulose, alpha cellulose, hemicelluloses, cellulose, lignin, extractives soluble in acetone, alcohol, hot water, and cold water and ash were measured as 87.59, 56.99, 30.59, 47.20, 25.16, 5.90, 2.53, 4.41, 1.79 and 1.79 percent, respectively. Also, the average of fiber length, fiber diameter, lumen diameter and cell wall thickness were measured as 0.96 mm, 26.45 mm, 15.48 mm and 5.49 mm, respectively. The averages of slenderness, flexibility and runkel coefficients were calculated as 36.29, 58.50 and 0.71, respectively. The results showed that, the debarked branches of grape trees, the amounts of holocellulose, alpha cellulose, hemi cellulose and cellulose are more than the branches with bark and debarked branches contains less lignin, extractives and ash compared with branches with bark. Also the results showed that dimensions of the fibers including fiber length, fiber diameter and fiber lumen diameter, except cell wall thickness, decreased with increasing of height.

Understanding the wood technological features depends on anatomical characteristics of the wood itself. Unfortunately, researchers in Iran have not focused on this issue recently. There are many trees and shrubs in the desert areas of Dasht-e Kavir and Dasht-e Lut whic woody anatomical features are not yet studied. We studied one of these species, Calligonum comosum (Polygonaceae). Three mature shrubs were selected and small cubic samples of woody stem and root were taken. Micro-sections were obtained with microtome and after dying with Astra-blue and Safranin the sections were mounted in Canada balsa and the anatomical features were investigated. The results showed that differences between roots and stems exist. The distinct growth rings in the stems and indistinct rings in the roots, the presence of gums in the stems and absence in the roots, and lower ray width of the stems compared to the roots were observed and inherent characteristics that have been reported by other researchers were determined. The most important difference between Calligonum comosum’s roots and stems is parenchyma-like fibers in the thin-walled roots which cannot be distinguished from axial parenchyma. The ground tissue of woody roots is parenchymatous cells full of starches, which probably can be related to the drought situation of deserts. The bark of Calligonum comosum contains priderm and sclereid cells which make the bark stiff and hard. Also the properties of particleboard produced from Calligonum comosum’s wood showed that boards has at least technical characteristics of European Standard EN 312 and hence the cultivation of this species for stoping of erosion of soil is advised and it is suitable species for desertification and its wood can be used to produce wood based panel.

This study has been undertaken to investigate the effects of the utilization of polyester fibers residues in improving the mechanical properties of wood plastic composites. Two types of polyester fibers (carpet fibers and polish fibers), high density polyethylene and 40wt% poplar wood flour, 2wt% maleic anhydride grafted polyethylene (MAPE) and ethylene- glycidyl methacrylate copolymer (E-GMA) as coupling agent were used. After two-stage mixing, the resulted granules were hot pressed at160oC, under 10 MPa pressures to produce test boards measuring 20×20×0.7 cm in dimensions. Results from measurement of mechanical properties have shown that with increasing the amount of polyester fibers (carpet fibers and polish fibers), tensile modulus of elasticity of wood plastic composites decreased and the flexural modulus of elasticity increased. Also increasing the amount carpet fibers, tensile, and flexural strengths of wood plastic composites-carpet fibers increased and the maximum of flexural strength is in a sample that contained 20 wt% carpet fibers. But using 10 wt% polish polyester fibers is efficient for increasing the flexural and tensile strengths of wood plastic composites-polish fibers. Then the composites containing the optimal polyester (polish fiber 10% and carpet fibers 20%) having optimum mechanical strength were used for TGA and DSC testes to determine the thermal behavior of the composites. Thermal analyses results have shown that with addition of polyester in the wood plastic composite, the percentage of crystallization, temperature of crystallization and the temperature of stability was reduced and the degradation temperature of the composite was also lowered. Morphologic study by Scanning Electron Microscopy indicated that with the increasing the percentage of polyester fibers, denser and smoother of the fracture surface of the composite appeared.

In this study the effect of nano-wollastonite usage in three level (0, 3 and 6 percent per dry by weight of the cement) and the mixture ratios of lingocellulosic material to cement in three level 10: 90, 20: 80 and 30: 70 on physical, mechanical and microscopic properties of composite made from kraft fibers- cement was investigated. Three replicates for each treatment and 27 experimental boards were manufactured. Specimens were prepared according to DIN- EN634 standard test methods to measure mechanical and physical properties. Mechanical and physical properties including compression strength, internal bonding (IB), thickness swelling after 2 and 24 hours immersion in the water and density were measured. Micro- structural properties of composites were evaluated by SEM images. The results showed that compression strength, internal bonding and density increased at higher levels of nano-wollastonite in the boards. By increasing the nano- wollastonite, dimensional stability was significantly improved in comparison to the control boards. SEM images showed that the micro- structure of the boards were improved by increasing the nano-wollastonite content.

One of major causes of the failure of production companies in the international markets is referred to the lack of their competitiveness with competitors. Therefore, the purpose of this study was to determine and ranking of the effective indices on competitiveness of Iran’s furniture industry by analytical hierarchy process. For this purpose, reviewing and investigating of researches carried out by others and interviewing with a numbers of specialists, the effective indices on competitiveness of Iran’s wooden furniture industry were divided into4 main groups and 19 sub-indices. Importance degree of the indices and sub-indices were determined after collecting expert’s opinion by AHP method. The results showed that main indices such as economic, technical, materials, human being indices have highest weight values respectively. Successful designing sub-indices were dramatically higher than the other sub-indices and after that the sub-indices of raw materials, sustainable management, professional human resources, standard development, sustainable supply, branding have allocated highest priority in AHP method respectively.

In this study, the effect of the type of polymer including polyvinyl chloride and high density polyethylene in the production of wood plastic composite was studied. Two forms of canola straw waste, with and without pith (depithed), in combination with wood flour were used. Five levels of lignocellulosic material were used consisting of 100% wood flour, 100% canola flour including pith, 100% depithed canola flour, 50% wood flour plus 50% canola flour with pith and 50% wood flour plus 50% depithed canola flour. Physical properties of boards including thickness swelling and water absorption after 2 and 24 hours immersion in water and mechanical properties such as screw withdrawal strength perpendicular to the surface, flexural strength and modulus of elasticity were evaluated according to EN. The results of this study showed that wood plastic composite made of high density polyethylene had better physical and mechanical properties compared with polyvinyl chloride. Using canola flour combined with wood flour lead to increasing flexural strength and modulus of elasticity, but decreased screw withdrawal strength perpendicular to the surface. Using lignocellulosic filler material containing 50% wood flour and 50 % depithed canola flour combined with high density polyethylene powder can produce wood plastic composite board with suitable physical and mechanical properties.

In this research, the potential of cellulose nanofibers to reinforce high yield kraft pulp (HYKP) produced from Populus deltoides clone 69-55 wood for making unbleached kraft liner board (UTKL) was investigated. The variable conditions of cooking were included the cooking time and temperature each at two levels. Sulfidity and active alkali were constant in the all cooking and liquid to wood ratio was 4 to 1. Optimum pulp was selected according to the pulp yield and kappa no. to be reinforced by cellulose nanofiber. Then, the pulp was refined by PFI mill to reach 385 ml. CSF. The cellulose nanofiber was added in three levels (5, 10 and 15%) to HYKP, then mixed for 5 min. and handsheet was made by special wire. The result indicated that 15% addiition of cellulose nanofiber to high yield kraft pulp increased tensile index by 68%, burst index by 51.32%, tear index by 21.51%, bending stiffness index by 120.14% and ring crush tests (RCT) by 124.59%, compared to the HYKP. Therefore it is recommended that nanofiber can be added to HYKP for UTKL production based on the yield and also physical and strength of reinforced pulp.

This study focuses on cooking conditions of cotton linters using in Parchin Chemical Company to achieve optimum cooking conditions and provide special cooking table for every linter to enable the above mentioned factory to adjust cooking conditions for linters to obtain higher quality products. In this respect, 4 types of linters from Turkey, Uzbekistan, Turkmenistan, and Iran were collected from the mentioned factory and pulped in two steps using 4 hours cooking time in every step. Cooking conditions were selected in 3 levels of 130, 150 and 160oC; and various Active Alkali charge (AA%) in each step and then the cooking yield, ash content, micro kappa, pentosan, copper number, carboxyl group, WRV, viscosity, alpha cellulose and acid insoluble materials were measured for each set of conditions. Results showed that optimum cooking conditions for Turkey linter were at 130oC and AA% (8%-8%); Uzbekistan linter, 130oC and AA% (12-%-4%); Turkmenistan linter, 130oC and AA% (12%-4%); Iran linter, 130oC and AA% (14%-2%). Hence, based on cooking conditions, the linters can be classified into 3 grades such as Grade 1 (Turkey), Grade 2 (Uzbekistan and Turkmenistan) and grade 3 (Iran).

The objective of the research is to forecast the trend of the printing and writing paper consumption in Iran for a five-year period using both modern and classical methods. In order to do the forecasting, predictability of time series was primarily studied using Durbin-Watson and Runs tests. Then, artificial neural network model (multilayer perceptrons (MLP)) and univariate and multivariate classical forecasting models such as univariate single exponential smoothing (SES), double exponential smoothing (DES), holt-winters exponential smoothing (HWES) and Box- Jenkins (ARIMA) models, and multivariate econometric model all together were compared in terms of the standard statistical measures. Finally, the consumption of printing and writing paper in Iran was forecasted up to the year 2017 using the most appropriate model. The results of both the parametric test of Durbin-Watson and non-parametric test of Runs show that, the printing and writing consumption series is non-random and predictable. The results of comparing different forecast methods showed that the artificial neural network model has higher forecasting accuracy than the classical models and it is more appropriate for the five-year forecast period. Also, the results of forecasting by using neural network model (MLP), revealed that the printing and writing paper consumption in Iran is forecasted to increase by 5.3%, from around 375 thousand tons in 2012 to 420 thousand tons in 2013, but it falls over the five-year forecast period, from 5.3% in 2013 to 0.07% in 2017.

Tension wood (TW) and normal wood (NW) of Populus nigra was analyzed to determine its suitability for pulp production. Biometric characteristics of the normal and tension wood fibers were measured. Wood samples were pulped using kraft pulping process. Mechanical and physical properties of the pulp hand sheets were measured. The results showed that comparing to normal wood, the tension wood fibers had bigger Rankle coefficient and aspect ratio, while the flexibility of normal fibers was better than tension wood. Results showed that the pulp yield of tension wood pulp was 13 percent greater than normal wood. Also, applying the same pulping condition led to a lower kappa number in tension wood. Determination of mechanical properties indicated that the tensile and burst strength of hand sheets obtained from tension wood were comparatively lower than that of normal wood. Optical properties measurement showed an improved brightness and whiteness for tension hand sheets comparing to normal wood papers.

Importing of wood has been considered as a solution to supply raw material in Iranian paper industry because of wood shortage. Therefore, the effect of mixing the imported aspen round wood with the two native hardwood forest species including hornbeam and beech on the optical and mechanical properties of CMP pulp was investigated. Cooking conditions consist of maximum temperature at 170oC with a liquor-to-wood ratio (L/W) of 7, and chemical content of 20% based on the oven-dry weight of the wood chips. CMP pulps were prepared at different cooking times of 30 to 120 minutes using 20, 30, 40, 60, and 100% aspen wood in combination with the two species to achieve the yield of nearly 85%. Standard laboratory hand sheets were made after refining the pulp 300 ml CSF, and then the strengths and optical properties were measured. Statistical analysis of the results showed that there were significant differences among the properties of CMP pulps by increasing the aspen wood ratio. All the properties have been improved except opacity of the paper. The required strength of newsprint and printing/writing paper made in Mazandaran wood and paper industries (MWPI) could be achieved by mixing of 20 and 30% imported aspen wood to the native species currently used, respectively.

This research was conducted to evaluate the effect of chemical treatment of wood flour on physical, mechanical and morphological properties of polypropylene-nano SiO2 hybrid nanocomposite. For this purpose, wood flour was treated with sodium hydroxide and benzyl chloride and to ensure the chemical treatment, Fourier transform infrared (FTIR) spectroscopy tests was done on the treated and untreated wood flour. Wood flour (40%) with 60% weight ratio with polypropylene and 4% maleic anhydrate grafted polypropylene coupling agent was compounded in extrusion mixture. Also Nano SiO2 at 0, 1, 3 and 5% as filler was used. The specimens were manufactured using injection molding technique. Then mechanical tests such as bending resistance and modulus and physical tests such as water absorption and thickness swelling were measured according to the ASTM standard. Also morphological features of the Nano composites were determined using Scanning Electron Microscopy (SEM). Results showed that the bending resistance and modulus increased with by chemical treatment but water absorption and thickness swelling were decreased. With increasing the Nano SiO2 to 3% the mechanical properties increased but adding further amount reduced the mechanical properties. With increase of SiO2 Nano particles to 5% the water absorption of Nano composites were increased, but thickness swelling was decreased. The results of SEM showed an improvement in interface between filler and matrix by chemical treatment Adding 3% can be considered suitable.

In this study, the effect of adding zinc oxide nanoparticles (ZnO) on color change and adhesion strength of polyurethane clear coat in elm (Ulmus glabra) wood was investigated. ZnO nanoparticles at the dosage of 0, 0.25, 0.50, 1, 1.50 and 2 wt% were dispersed in coating. TEM (Transmission electron microscopy) images were used to investigate the dispersion of nanoparticles in coatings matrix. Results of investigation showed the dispersion of nanoparticles in polyurethane coating indicating that the best dispersion of nanoparticles was obtained in coating containing 1 wt% nano. Increasing the dosage of nanoparticles to 2 wt%, reduced dispersion of nanoparticles and aggregates of nanoparticles were observed in coating. Investigating the adhesion strength of coating showed that the highest value of adhesion was in nanocomposite coating with 1 wt% nano but higher ratios of nanoparticles had negative effect on coating adhesion. Results also revealed that adding ZnO nanoparticles, changed color of samples coated with nanocomposite coating but it was not significant in low content of nanoparticles.

In this study deinked pulp (DIP) produced in Latif Company which contains a mixture of printers edgings, mixed office waste (MOW) and recycled mechanical paper was used to investigate the effect of bleaching variables on pulp and paper properties. Six variables of bleaching process including the amount of hydrogen peroxide, sodium hydroxide, and sodium silicate, bleaching time, bleaching temperature and final pH were optimized in order to improve wet and dry tensile index of handsheet. Design Expert software was used for analyzing and modeling. Results were investigated in from of central composite design (CCD) and response surface methodology (RSM) was modeled and analyzed. Optimized wet and dry tensile were obtained by appling 1.55% hydrogen peroxide, 1.55% sodium hydroxide and 1.55% silicate, 90 minutes bleaching time, 83oC bleaching temperature, and final pH equal to 8.5. The result showed that bleaching variables affect significantly the optical properties as well as mechanical strength of paper, and also dry and wet tensile strengths can be improved by optimization of bleaching condition.

In this research, the effect of oil heat-treated on the outdoor performance of coatings namely, transparent resin stain, alkyd paint, semi-transparent cellulosic stain, acrylic paint coated on eastern cotton wood was investigated. For this purpose, sound specimens with the dimensions of 50×50×2 mm (Longitudinal × tangential × radial) were prepared from sapwood. Test samples were treated with canola oil at temperatures of 180, 200 and 220oC for 4 hours. The coatings with the wet film thickness of 150mm were applied on the specimens using an applicator. The coating adhesion was measured according to ASTM D 4541 standard, and the color characteristics of the coating were measured according to ASTM D 2244 before and after a natural weathering for 180 days. The statistical analysis of the color change data showed that the effect of the oil heat-treatment on the color change depended on coating type. The statistical analysis of the adhesion strength data showed that the adhesion strength depended on the combination of weathering, oil heat-treatment and coating type.