مجله تحقیقات علوم چوب و کاغذ ایران
سال سی‌ام شماره 4 (پیاپی 53، زمستان 1394)

This study has been conducted to determine morphological characteristics of fibers and amount of chemical components of grapevine branches cultivated in Astara in province of Guilan. For this purpose the number of 53 branches, with same size and diameter, were cut from some grapevine and sent to laboratory of wood and paper industries in Islamic Azad university Astara branch. To separate the fibers and for studying their morphological characteristics, wooden chip sampling from the branches was conducted at 3 heights of them (5%, 50% and 75%). Fiber separation was done by method (Franklin 1954) and then dimensions of fibers and their biometric coefficients were determined. From a number of separated branches, wood flour was prepared in two modes of with skin and without skin and then, percentage of chemical components of them was determined according to TAPPI standard. The overall average percentage of holocellulose, alpha cellulose, hemi cellulose, cellulose, lignin, acetone extractives, alcohol extractives, hot water extractives, cold water extractives 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 total average of fiber length, fiber diameter, lumen diameter and cell wall thickness were measured as 0.96 mm, 26.45 µm, 15.48 µm and 5.49 µm, respectively. Also, the total average of slenderness, flexibility and runkel coefficients were calculated as 36.29, 58.50 and 0.71, respectively. The results showed that, in the debarked branches of grapevine trees, the amounts of holocellulose, alpha cellulose, hemi cellulose and cellulose are more than with skin branches and debarked branches have less lignin, extractives and ash than with skin branches. 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 of many wood technological features depends on anatomical characteristics which, unfortunately, researchers in Iran have not focused on recently. There are many trees and shrubs in the desert areas of Dasht-e Kavir and Dasht-e Lut with unstudied woody anatomical features. 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 micro-tome and after dying with Astra-blue and Safranin the sections were mounted in Canada balsam. The results showed that many differences between roots and stems exist, such as 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, inherent characteristics that have been reported by many other researchers. 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 has priderm and sclereid cells which make the bark stiff and hard. Also the result of particleboard of fabricated of Calligonum comosum’s wood showed that boards has at least technical characteristics of European Standard EN 312 and hence the silviculture of this species for stooping of erosion of soil and is suitable species for desertification and its wood can be used for producing of wood based panel.

This study has been undertaken to investigate effects of synthetic waste fibers of polyester in improving mechanical properties of wood plastic composites. Two types of polyester fibers (carpet fibers and polish fibers), high density polyethylene along with 40 wt% wood flour of populus, 2 wt% of maleic anhydride grafted polyethylene (MAPE) and ethylene- glycidyl methacrylate copolymer (E-GMA) as coupling agent were used. After two-stage mixing, resulted granules were hot pressed (at160℃, under 10 Mpa pressures) to produce test boards measuring 20×20×0.7 cm in dimensions. Results from measurement of mechanical properties of the samples have shown that with increasing the amount of polyester fibers (carpet fibers and polish fibers), tensile modulus of elasticity of wood plastic composites decreases and increases his flexural modulus of elasticity. Also by increasing amount carpet fibers, the tensile, flexural strengths of wood plastic composites-carpet fibers increases and the maximum of flexural strength is in a sample that contained 20 wt% carpet fibers. But about the plush fiber, 10 wt% of it is efficient for increasing the flexural and tensile strengths of wood plastic composites-plush fibers. Then on the composites contained the optimal polyester (polish fiber 10% and carpet fibers 20%) for increasing the mechanical strength, TGA and DSC testes for experience the thermal behavior of the composites were analyzed. Thermal analyses results have shown that with addition of polyester in the wood composite plastic, are reduced the percentage of crystallization, temperature of crystallization and the temperature of stability and degradation thermal of the composite.Morphologic study by Scanning Electron Microscopy indicates that with the increasing percentage of polyester fibers, is more denser and smoother the integration between the fracture surface of the composite material.

In this study the possibility of nano- wollastonite usage in three level (0, 3 and 6 percent per dry weight of cement) and mixture ratios of lingo cellulosic materials to cement in three level 10:90, 20:80 and 30:70 on physical, mechanical and microscopic properties of composite made from kraft fibers was investigated. There were three replicatesfor each treatment and 27 experimental boards were manufactured totally. Specimens were prepared according to DIN- EN- 634 standard to measure mechanical and physical properties. Mechanical and physical properties including compression strength, interior bonding (IB), thickness swelling after 2 and 24 hours immersion into the water and density were measured. Micro- structural properties of composites were evaluated by SEM images.The results showed that compression strength, interior bonding and density increased by higher levels of nano- wollastonite content in the boards. By increasing of nano- wollastonite, dimensional stability was significantly improved in comparison to the control boards. SEM images showed the improvement of micro- structural boards by increasing the nano- wollastonite content.

One of major causes of the failure production companies in the international markets is referred to the lack of their competitiveness in comparison with competitors. Therefore, the purpose of this study were determining 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 especialista, the effective indices on competitiveness of Iran’s wooden furniture industry divided into the 4 main groups and 19 sub-indices. Importance degree of the indices and sub-indices were determined after collecting experts opinion by AHP method. The results showed that mainindicators economic, technical, materials, human being indices have highest weight values respectively. Successful designing sub-indices was dramatically higher than the other sub-indices and after that the sub-indices of raw materials, sustainable managem ent, professional human resources, standard development, sustainable supply, branding have allocated highest priority in AHP method respectively.

In this study the effect of type of polymer including polyvinyl chloride and high density polyethylene in production of wood plastic composite by using of canola straw waste in two forms, with and without pith (depithed), in combination with wood flour were investigated. Five levels of lignocellulosic materials 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 on the surface, flexural strength and modulus of elasticity according to EN were evaluated. 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 and using of canola flour combined with wood flour lead to increasing flexural strength and modulus of elasticity, but decreased screw withdrawal strength perpendicular on the surface. Using of lignocellulosic filler material by combining of 50% wood flour plus 50 % depithed canola flour combined with high density polyethylene powder can be produced wood plastic composite board with suitable physical and mechanical properties.

In this research, capacity of cellulose nanofibers to reinforce of high yield kraft pulp produced (HYKP) from Populus deltoides clone 69-55 for making unbleached top kraft liner (UTKL) was investigated. The variable conditions of cooking were included the cooking time and temperature each one in 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 reinforce by cellulose nanofiber. Then, it was refined by PFI mill beater to achieve 385 ml. CSF. The cellulose nanofiber was added in three levels (5, 10 and 15%) to HYKP, then mixed for 5 min. and handsheet made by special wire. The result indicated that 15% adding of cellulose nanofiber to high yield kraft pulp increased tensile index by 39%, burst index by 33%, tear index by 17.7%, bending stiffness index by 38% and ring crush tests (RCT) by 55.47%, respecting to the HYKP. In overall, it is recommended nanofiber adding to HYKP for UTKL making according to 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 to provide special cooking table for every linter as above mentioned factory can adjust cooking conditions for all linters to obtain higher quality products. In this respect, 4 types of linters from Turkey, Uzbekistan, Turkmenistan, and Iran were provided from mentioned factory and pulped in two steps by 4 hours cooking time in every steps. Cooking conditions were done in 3 level 130, 150 and 160 °C; and various Alkali charge (AA %) in each step and measured cooking yield, ash content, microkappa, pentosan, copper number, carboxyl group, WRV, viscosity, alpha cellulose and acid insoluble materials for any conditions. Results showed that optimum cooking conditions were obtained for Turkey linter at 130 °C and AC%(8%-8%); Uzbekistan linter, 130 °C and AC% (12-%-4%); Turkmenistan linter, 130 °C and AC% (12%-4%); Iran linter, 130 °C and AC% (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.

In this research Tension Wood (TW) and Normal Wood (NW) of Poplar were analyzed for pulp production using Kraft pulping process. After preparing samples, Biometric characteristics of the NW and TW fibers were measured and samples were converted to pulp. Pulp hand sheets mechanical and physical properties were measured and results were showed that NW fibers compared to TW fibers had a higher Rankle coefficient and aspect ratio. However the flexibility of NW fibers was better than TW fibers. Based on Results, although TW pulp yield was 13 percent greater than NW pulp yield but kappa number in TW was 45 percent lower than NW. Mechanical and physical properties of hand sheets indicated that the tensile and burst strengths of tension wood were comparatively lower than that of normal wood. Also the papers produced by equally mixture of TW fibers and NW fibers were showed higher tensile and burst strengths. Optical and color analyses of samples were showed an improvement in brightness and whiteness for TW hand sheets compared to NW papers. General speaking results were showed that presence of TW fibers inside pulp had not a significant effect on quality of produced pulp and papers.

Importing of wood is a solution to supplying raw material in the Iranian paper industry because of wood shortage. Therefore, the effect of mixing the imported aspen roundwood with the two hardwood native forest species including hornbeam and beech were perused on the optical and mechanical properties of CMP pulp. Cooking constant conditions consist of maximum temperature were 170 °C 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 handsheets were made after pulp refining by 300 ml CSF, and then the strengths and optical properties were measured. Statistical analysis of result showed that there were significant differences among of the properties of CMP pulps by increasing the aspen wood ratio. All the properties have been improved except opacity 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 used in currently, respectively.

This research with aim of evaluation the effect of chemical treatment of wood flour on physical, mechanical and morphological properties of polypropylene-nano SiO2 hybrid nanocomposite were done. For this purpose, wood flour with sodium hydroxide and benzyl chloride to chemically treatment. For ensure the chemical treatment, Fourier transform infrared (FTIR) spectroscopy tests was done on the treated and untreated wood flour. Wood flour at 60% weight ratio with polypropylene with 4% maleic anhydrate grafted polypropylene coupling agent in extrusion were mixed. Also Nano SiO2 with 0, 1, 3 and 5% as filler was used. The sample specimen were manufactured by using injection molding techniques. Then mechanical tests such as bending resistance and modulus and physical tests such as water absorption and thickness swelling according to the ASTM standard was done on the samples. Also for morphological investigation on the Nano composites from Scanning Electron Microscopy (SEM) was used. Results showed that the bending resistance and modulus increased with effect of chemical treatment but water absorption and thickness swelling decreased. With increase of Nano SiO2 to 3% the mechanical properties increased but adding further amount Nano particles reduced the mechanical properties. With increase of SiO2 Nano particles to 5% the water absorption in Nano composites were increased, but thickness swelling was decrease. The results of SEM showed an improvement in interface between filler and matrix with effect of chemical treatment Also transmittance of Nano SiO2 to 3% levels was good.

In this study the effect of adding zinc oxide nanoparticles (ZnO) on color change and adhesion strength of polyurethane clear coat in Elm wood species (Ulmus glabra) investigated. ZnO nanoparticles with concentration of 0, 0.25, 0.50, 1, 1.50 and 2 wt% were dispersed in coating. TEM (Transmission electron microscopy) images were used for investigate the dispersion of nanoparticles in coatings matrix. Results of investigate the dispersion of nanoparticles in polyurethane coating indicated that the best dispersion of nanoparticles obtained in coating with 1 wt% nano. Increasing concentration of nanoparticles to 2 wt%, reduced dispersion of nanoparticles and aggregates of nanoparticles observed in coating. Investigation adhesion strength of coating showed that the highest value of adhesion was in nanocomposite coating with 1 wt% nano but increasing nanoparticles more than this content, 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 dispersed deinked pulp (DIP) of Latif Company which includes a mixture of straw printers, mixed office waste (MOW) and mechanical recycle 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 in from of the central composite design (CCD) were investigated 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, 83 0C bleaching temperature, and final pH equal to 8.5. The result showed that bleaching variables affect significantly the optical properties sample 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, alkydi paint, semi- transparent cellulosic stian, 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 220 ° C for 4 hours. The coatings were the wet film thickness of 150µm 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.