yahya hamzeh

Environmental pollution and the various wastes produced globally have been of fundamental and worrying concern in recent decades. Waste from cigarette filters is among the most abundant and dangerous worldwide, discarded in the environment after use. The amount of this waste is increasing due to the rise of consumption globally. This study compared the possibility of reusing and recycling cigarette filters to produce electrospun nanofiber layers with Sigma cellulose acetate powder nanofibers, a valuable and important material in various industries. Cigar filters were collected and purified to produce the nanofibers, and the extracted liquid was studied using the GC-MS technique after purification. After electrospinning a 10% weight solution of cellulose acetate powder and cigarette filters with a composite solvent of acetone and dimethylacetamide, the morphology and surface of the produced fiber layers were examined using a FESEM microscope. FTIR-ATR was used to compare and analyse the chemical reactions of the two sources of cellulose acetate. According to the results obtained, gas chromatography-mass spectroscopy analysis showed that various chemical compounds exist in used cigarette filters, the most important of which is nicotine. Electron microscopy analysis showed that the purification of the cigarette filter had no adverse effect on fiber morphology before and after purification. Furthermore, the production of nanofibers with an average diameter of 150-400 nanometers from a source of recycled cigarette filters, like powdered cellulose acetate, was successfully performed, and the chemical properties and registered infrared absorption spectrum for both types of produced nanofibers had a high degree of overlap.

The growing demand for effective and environmentally friendly phenol removal methods has led to a growing interest in investigating the potential of using biomass-derived activated carbon. This research investigated the absorption process of phenol from wastewater using activated carbon adsorbents and activated carbon modified with copper in a batch system. Activated carbon was obtained from paper mill black liquor. The pore structure and morphology of unmodified and modified samples were investigated by BET and SEM. Modifying activated carbon with copper increased the specific surface area from 283.2 to 517.5 m2/g. The inhomogeneity in the modified AC absorbent surface is less compared to AC, and it also has a more regular surface in terms of particle size uniformity. The ability of prepared adsorbents to remove phenol in aqueous medium was evaluated by examining the effects of parameters such as adsorbent amount, pH, solution concentration, contact time, temperature effect. Based on the results, it was found that AC/Cu shows the highest adsorption rate after coming in contact with phenol solution with a concentration of 100 ppm for one hour at an optimal pH of 8. The adsorption of phenol by AC/Cu is consistent with the pseudo-second-order kinetic model. The absorption of phenol by the modified AC depends on the temperature and is an endothermic process. The increase in the amount of phenol removal with increasing temperature is more in AC/Cu. The study of the adsorbent saturation in the column system showed that AC/Cu is able to absorb more than 95% of the phenol solution with a concentration of 100 ppm up to a volume of 2700 mL. The findings of this study provide valuable insights into the field and pave the way for further research in the future.

Bio-resins obtained from lignocellulosic materials can be suitable alternatives for adhesives and resins obtained from fossil sources due to their renewable nature, availability of raw material and reduction of environmental pollution. The aim of this research is to optimally use the waste from cutting the side of medium density fiberboard (MDF), sugarcane bagasse waste, birch wood waste and cedar wood to prepare resin. In this research, bioresin was produced through acid hydrolysis of lignocellulosic materials by HCl gas. Then, FTIR spectroscopy was performed in four types of produced resins to identify functional groups. The physical characteristics of the resin, including the percentage of solids, viscosity, viscosity, density, and pH were evaluated for each of the resins. The shear adhesion strength of the prepared resins was also measured. According to the obtained results, the resin obtained from bagasse (R.B) showed better properties than other resins due to the reduction of viscosity (20.61 seconds), better penetration into the porous structure of wood, stronger adhesion and better washing resistance.

Chitosan with high molecular weight does not have the ability to penetrate the wood cell walls ‎and has little protective effects to increase the durability of wood. On the other hand, tannin can ‎easily be leached from impregnated woods and has a high leaching rate. The aim of this ‎research is to produce tannin-chitosan polymer and investigate the resistance to decay of ‎impregnated samples with it. Beech wood was used in this study. Initially, acid hydrolysis ‎method was used to reduce the molecular weight of chitosan. Then different ratios of ‎hydrolyzed chitosan and tannin were combined to find the best formulation. Vacuum-pressure ‎impregnation method was used. After impregnation and polymerization of tannin/chitosan, ‎water leaching test and resistance to decay against white and brown rot fungi were performed. ‎The results showed that adding hexamine to tannin-chitosan polymer leads to a reduction in the ‎percentage of water leaching of the protective material from wood and improves the fixation ‎and durability of the materials. Also, the resistance of wooden samples against brown and white ‎rot fungi has increased. The chitosan ratio increasing in the tannin/chitosan mixture led to an ‎increase in the leaching of substances and a decrease in the resistance to decay of impregnated ‎woods.‎

In this study, the effect of changes in pH and molar ratio on the properties of melamine formaldehyde resin for impregnating decorative paper was investigated. The physical properties of the resin such as free formaldehyde, resin shelf life, and the percentage of resin solids contents were investigated in different conditions Also, the molecular structures of resin were studied using FTIR spectroscopy and thermal analysis of resins through TGA. The results showed that a higher pH improved the characteristics of the resin and melamine coating, while increasing the molar ratio of formaldehyde to melamine weakened the characteristics of the resin and coating. In addition, the results showed that the changes observed in the resin caused by The variables of molar ratio and pH have no significant effect on the thermal properties of the resin.

In this study, a short ozonation pretreatment method was used to accelerate the extraction and purification of chemical compounds in bagasse and its unbleached soda paper pulp. In order to optimize and economize energy consumption, the operating conditions of ozonation were evaluated in three mediums (acidic, neutral and alkaline) and in different time intervals of 20, 60, 120 and 180 minutes. To investigate the effectiveness of medium and time of ozone on the chemical structure of the bagasse and its unbleached soda paper pulp, the infrared spectroscopy, X-ray diffraction, the content of the carboxyl group was used through conductivity titration and polymerization degree measurement. The results showed that the acidic medium had the highest amount of lignin removal and the least amount of cellulose and hemicellulose destruction and was chosen as the most suitable medium for the ozonation process and since the highest lignin removal occurred in the first 20 minutes reaction, so to remove lignin, the long ozone pretreatment is not required and short ozone can save energy and cost of pretreatment and in addition, cellulose and hemicelluloses destruction which are valuable compounds, are significantly reduced.

In this research, the fractionation of canola stalks with glycerol as a green solvent and also the use of remaining fibers for the production of pulp were evaluated. Fractionation of canola stalk were performed at various temperatures and times with alkaline or acidic catalysts, calcium chloride as additive, different L:S and glycerol to water ratios. The results show that the screened yield remains constant or decreased with increasing the temperature after 170°. Increasing the cooking time after 3 hours has a negative effect on the screened yield. The influence of acidic catalyst on increasing the screened yield was significantly greater than that of alkaline ones. L:S ratio up to 12:1 increases the screened yield but more than this, the screened yield remains constant or decreases. Handsheets were prepared and tear and tensile indices and RCT strength were measured as 2.07 mNm2/g, 14.38 Nm/g and 135.4 N, respectively. According to the results it is possible to produce pulp with strength properties similar to chemi-mechanical pulps. The results also showed that glycerol is suitable for the canola stalk fractination and 88% of hemicelluloses, 44% of cellulose and 30% of lignin are found in the black liquor, which could be used as platform chemicals in a biorefinery.

The perishable nature of fruits and vegetables makes their shelf-life limited. Environmental factors, transportation and preservation conditions through postharvest can decrease the storage time and quality. Therefore, prolonging supply period of fruits and vegetables by using safer postharvest treatments lead preservation methods to edible coatings. Active edible coatings include different types of functional substances can be considered as a preservation method to improve strategies for improving the quality, safety and shelf-life of fruits and vegetables after storage. In this article, an overview of the basics and methods of using lignocellulosic materials to create edible coating films and the recent challenges and developments of this type of lignocellulosic material application are presented. A review of the scientific sources shows that cellulose, lignin and chitosan are polysaccharides that have high potential in the production of edible coatings. These types of coatings are commonly odorless, tasteless, non-toxic, non-allergenic, water soluble, transparent, and resistant to oil and fats. In addition, these coatings can be good carriers for active additives, antimicrobial compounds, antioxidants, anti-browning agents, texture enhancers, and nutraceuticals to prevent unwanted reactions and enzymatic or biochemical damage to inhibit microbial decay and enzymatic or biochemical damage and prevent physical textural deterioration in fruits and vegetables during storage.

In this study, efficient hybrid hydrogels as drug delivery platforms were synthesized using Kraft lignin, a biopolymer obtained from the alkaline paper industry, chitosan and glutaraldehyde as a crosslinker. The ratio of lignin was an important variable factor of this study and its effect on morphology and mechanical properties were studied. The characteristics such as compressive property, swelling capacity, drug release, degradation time, and SEM imaging of the hydrogels of chitosan and chitosan/ lignin with different amount of lignin were investigated. Also, paracetamol drug was selected as a drug model. The results showed that the glutaraldehyde crosslinker can effectively create a crosslinked structure, so that the durability and stability of the hydrogels in the desired conditions is up to 15 days for the pure chitosan sample and 11 days for the lignin chitosan sample, respectively. Although the shortest shelf life (5 days) corresponds to the highest amount of lignin, which was a shorter period of time, but it gives enough time for the drug to be completely released. The results showed that although the hydrogel structure is weakened by increasing the percentage of lignin, the drug was released faster with the increasing of lignin, which can be considered as a factor for changing the release rate of drug according to the intended application. The highest amount of release was observed in hydrogels with the highest amount of lignin, so that in the first two hours, its amount was about six times higher than that of pure chitosan hydrogel.

Cellulose nanofiber (CNF) and chitosan nanofiber were incorporated into conventional pigment coating structures, and their effects have been investigated on the properties of the Testliner. Hence, Testliner paper samples were double-coated, and the addition of cellulose nanofiber and chitosan nanofiber was conducted into the formulation of top layer coating. The results indicated that in comparison with uncoated samples, coating improved roughness and significantly decreased air permeability of the Testliner. Although the application of conventional pigmented coatings reduced burst strength and tensile strength indices, the addition of both CNFs and chitosan nanofiber compensate for the losses so that high gain was obtained for chitosan fiber-containing formulation. As was expected, a significant enhancement of brightness was achieved due to the double-layer coating of the Testliner. It can be concluded that incorporating these nanofibers as additives into conventional pigmented coatings can play an influential role in improving the properties of the Testliner board as a valuable packaging material.

In this research, the physical and mechanical properties of the surface sizing liner papers with starch formulation with soda and formacell lignins have been investigated. The soda and formacell lignins from the remaining black liquor were separated and then was replaced with anionic starch in 30, 50, 70, and 100 ratios. In addition, 0.3 g/m2 alum as a cationic agent was charged to the suspension. The results of this study show that even by 100 % replacing starch with both types of lignins, the physical characteristics (air resistance, cobb, coarseness) and mechanical properties of surface-sized paper have been improved compared with control paper. According to the results, 50/50 lignin/starch ratio improved the mechanical and physical properties better and was determined as optimum level. For soda lignin without alum, tensile (36.21 N.m/g) and burst (1.58 Kpa.m2/g) indices increased by 55 and 35 % respectively, compared with the control in the optimum level. For formacell, lignin/starch in 50/50 ratio without alum, the tensile and burst indices were increased 47 and 27% respectively, compared with the control sample. According to the results, it is possible to replace at least 50% of starch with the above-mentioned lignins, which will play an important role in food security and add value for pulp mills.

The aim of this study was to determine effective criteria in optimizing energy consumption in Kaveh paper industry company by using the analytic hierarchy process (AHP). For these purposes, after a review of previous studies and some interviews with experts, effective criteria in optimizing energy consumption in Kaveh paper industry company were divided into 6 main categories and 49 subcategories. The degree of importance of the main categories and subcategories was determined after obtaining expert opinions using Expert Choice software. The results of this study showed that the main criteria in optimizing energy consumption are: process modification, technical knowledge, and manpower, implementation of preventive maintenance (PM) system, use of intelligent control systems and process monitoring, and energy recovery. Process modification criterion with a weight of 0.38 has the highest priority in optimizing energy consumption. In addition, among 26 sub-criteria effective in optimizing energy consumption in Kaveh paper industry company, sub-criteria improving stock pulp preparation, the level of education of factory personnel, work experience of personnel, reduction of stops, research and development, online moisture and basis weight paper measurement sensor, respectively, had the highest importance with the weight values of 0.209, 0.119, 0.116, 0.113, 0.066, 051 and 0.087. The inconsistency ratio of the research was 0.01 which shows the results have stability and compatibility. The results can be used to accelerate the implementation of the process of optimizing energy consumption in other paper mills in Iran.

The conservation and preservation of historical paper as cultural and historical heritage against harmful factors such as microorganisms is important. It was shown that the thiophanate methyl antifungal in 200 PPM concentration could inhibit destructive effect of several fungi on paper without negative effects. However, it is necessary to complete the studies by investigation the effect of thiophanate methyl on other materials used in historical paper, including inks.In this research, the effect of thiophanate methyl on gall ink as the most widely used ink in historical paper was studied.For this purpose, after the ink preparation and placing it on the paper surface, the samples were immersed in a solution containing thiophanate methyl, and the effect of accelerated aging on gall ink and treated gall ink were investigated by determination of pH, color, and tensile strength of paper as well as by FTIR-ATR spectroscopy and SEM microscopy. The pH results showed that the gall ink is highly acidic, which causes the acid hydrolysis reaction lowering the paper strength. Moreover, thiophanate methyl in concentration of 200 ppm brightens the color of the gall ink. Due to the adverse effect of paper immersion on paper strength, the treatment should be conducted by spray method. Overall, although thiophanate methyl could protect the historical papers against fungus, but it showed various adverse effects on the gall ink that should be considered.

The lower mechanical properties of paper made from recycled fiber is due to their inherent properties of the used fibers. In order to improve strengths, various polymers such as cationic polymer are used, while today the global trend is the utilization of natural and renewable materials. In this study, two biopolymers including chitosan (Ch), isolated soy protein (ISP) along with glutaraldehyde (GA) were used to optimize the mechanical properties of the tissue paper made from the de-inked fibers. For this purpose, at the first chitosan solution with loading level of 0% to 2%, then glutaraldehyde with loading level of 2% to 6%, and finally isolated soy protein with 1% to 3% levels were added to the pulp suspension. The properties of handsheets were measured by standard test methods and the results were modeled using Design Expert.10 software and response surface method (RSM). The results and obtained models showed that addition of these additives did not make a significant difference on brightness of the hand sheet paper compared with the control sample. However, the addition of these additives increased the dry and wet tensile and tear strengths, which in the optimal addition level the increasing levels for mentioned properties were 145%, 35% and 70%, respectively, compared with the control sample. The increasing rate of tensile and tear resistance were higher than increasing rate obtained by conventional dry strength agents, such as cationic starch.

Mineral fillers are the second most important elements used in papermaking. Increasing filler content in writing and printing papers without decreasing the mechanical properties is always desired for enhancing the optical and printing properties and cost effective papermaking process. In this study, to increase the filler content in paper, calcium silicate was loaded by in situ precipitation on bleached bagasse fibers. The effect of reaction temperature on the loading and precipitation of calcium silicate on fibers was investigated using ash content measurement, XRD spectroscopy, SEM imaging and EDX analysis. Finally, the effect of treated pulp content on the physical and mechanical properties of pulp was investigated. Ash measurement results showed that calcium silicate precipitation in bleached bagasse fibers was achieved and the amount of calcium silicate loading increased with increasing the reaction temperature. XRD spectroscopy confirmed the formation of calcium silicate and calcium carbonate, and their precipitation in cell walls, lumen and interior spaces of the bleached bagasse fibers was confirmed by SEM imaging. The precipitated minerals on the fiber surface consisted of particles with various diameters. The EDX analysis confirmed the presence of silica and calcium in the treated fibers. With the constant basis weight of 80 g/m2, brightness and apparent density increased significantly, however the paper strength decreased by increasing the content of treated fibers in handsheet paper.

Due to the limited oil resources and environmental effects of coating films from petroleum and plastic materials, today there is special attention to the production, optimization and consumption of natural biopolymers. The use of biomass as a sustainable and renewable material for the production of films from lignocellulosic sources such as wheat straw and rice straw has increased in recent years. In this study, the preparation of a biofilm based on dissolution of rice straw was investigated. Initially, sodium hydroxide was used in different concentrations to dissolve rice straw. Various treatments such as freezing-thawing and acid pretreatment were used to improve the dissolution of rice straw. Based on the calculation of dissolution yield, good results were not obtained for dissolving rice straw in sodium hydroxide solution. However, by applying chemical acid pretreatment, soda/urea solution and freezing-thawing sequence, dissolution efficiency was improved and films were produced using the molding method. The physical and chemical properties of the prepared films were analyzed by analysis methods including the transparency of the solution as an indicator of the quality of dissolution, optical microscope and scanning electron microscopy and EDX test. The results showed that the resulting film was dissolved in acid pretreated rice straw and then dissolved in soda/urea solution with optical properties, uniformity and topography of a suitable surface that can be used as a coating in the packaging industry.

Pyrolysis acid or wood vinegar is a dark liquid derived from the condensation of steam and ‎smoke emitted by thermal pyrolysis of wood or any other lignocellulosic material. In this study, ‎a heating furnace was first designed to allow a precise temperature-time program. The wood ‎from three different species including oak, citrus and cypress were pyrolyzed under a specific ‎temperature-time schedule. The smoke emitted from the furnace were cooled and condensed in ‎a 20 m pipe using the flow of cold water, and then was dumped in a container as liquid. ‎Pyrolysis was performed at three different temperature ranges of 200, 260 and 330 ° C. The ‎obtained pyrolysis acids had different color and acidity depending on the temperature and ‎species of wood used. Under the heating conditions used in this study, cypress had lower ‎pyrolysis rate than hardwoods. The weight percentage gain of the treated beech and pine wood ‎varied from 5 to 35%, which was depended to the wood species for treatment, the temperature ‎as well as the wood used for pyrolysis. Acid pyrolysis at higher temperatures resulted in higher ‎weight percentage gain. The acid pyrolysis obtained at lower temperature was leached at ‎higher rates from treated wood. Also the wood types used for pyrolysis had significant effect on ‎the amount of lechant from treated woods. ‎

Stickies are one of the main challenges in the papermaking industry, especially in recycling process of old corrugated containers (OCC). Application of a fixing cationic polymer is one of the main approaches to control these harmful substances. However, it is obvious that these agents besides fixing characters could also influence the final product properties. Therefore, in this study, the effect of using an industrial cationic polymer i.e. GL, as a stickies control agent on mechanical properties of hand-sheets made of OCC fibers, was assessed at three levels of 0.4, 0.8 and 1.2% (based on pulp dry weight) and at two pH ranges of 4 and 7. The characterization of the GL by FT-IR spectroscopy demonstrated that it was synthesized based on poly (diallyldimethylammoniumchloride). The results showed that use of the cationic polymer enhanced the strength properties of the hand-sheets by influencing formation and inter- fiber bonding through fixing and flocculating the stickies and fines into the fibers network. These respective enhancements were measured at pH ranges of 4 and 7 as follows: Tensile strength of 35 and 30%, burst strength of 12 and 10%, ring crush test (RCT) of 29 and 21%, Concora medium test (CMT) of 19 and 32% and tear strength of 10 and 13%. It can be concluded that 0.4 % GL cationic fixing agent could be proposed as optimum value at pH =7 for industrial applications

Bagasse carbohydrates, which are mainly consist of cellulose and hemicelluloses, are important raw materials in chemical industries; because they can be easily prepared from biomass in large scale, their application is simplified in large scale. Derivation and purification of biomass chemicals are difficult, costly and require the use of complex methods with environmentally dangerous chemicals and solvents. Therefore, researchers are looking for simpler, cheaper, safer and environmentally friendly compounds and processes. The use of deep eutectic solvents has been reported as one of these methods in biomass processing. In this study, the use of new oxalic acid-choline chloride and lactic acid-choline chloride deep eutectic solvents for bagasse treatment was investigated. Results indicated that these new solvents were effective in the solubilization and extraction of short-chain and amorphous carbohydrates, especially hemicelluloses; as the final processing yields were respectively reduced to about 50 and 59%, and the main part of degradation belonged to the hemicelluloses. Cellulose to holocellulose ratio was increased in all treatments to about 90%. The lactic acid-choline chloride solvent was effective in lignin solvation, as the lignin content was reduced to 6.2%, while oxalic acid-choline chloride solvent did not have an ideal efficiency toward lignin removal, and the least amount of lignin in treated product was about 11%. Also, the viscosity drop of cellulosic pulp in lactic acid-choline chloride solvent-treatment was much less compared to oxalic acid-choline chloride solvent-treatment, as the cellulosic pulp viscosity for these treatments were 11.1 and 4.3 cp., respectively.

In this research, hot water pre-extraction of wheat straw followed with monoethanolamine-Anthraquinone and soda-Anthraquinone pulping was investigated. The pre-extraction satge of hemicelluloses with process variables of the temperature of 150 ◦C and the time of 45 minutes with water/straw ratio of 4/1 was selected as the optimum treatment. Among the pulps produced from unextracted wheat straw and pre-extracted wheat straw, monoethanolamine-AQ pulps have the highest yield. The highest drop in yield is observed in the case of soda–AQ pulp produced from pre-extracted wheat straw. In the same process conditions, the kappa numbers of monoethanolamine-AQ and soda-AQ pulps from unextracted wheat straw show the lower amounts than the pulps from pre-extracted wheat starw and the lowest kappa number belongs to monoethanolamine-AQ pulp made from unextracted wheat straw. Tensile indices of the pulps produced with pre-extracted wheat straw were decresedsignificantly. Burst index of soda-AQ pulp from pre-extracted straw was slightly improved a little decrease in the burst index of monoethanolamine-AQ pulp from pre-extracted straw occurs.The tear index of monoethanolamine-AQ pulp is significantly increased after the pre-extraction of the straw. The brightness of pulp from both processes is slightly decreased after pre-extraction. The opacity of soda-AQ and monoethanolamine-AQ pulps from pre-extracted straw was increased and decresed respectively.

An important source of lignin is the spent pulping liquor, known as black liquor, due to high volume produced of black liquor the treatment of it is very important for economic and environmental reasons. Alkali lignin can be extracted from black liquor in pulping process to produce value-added chemicals, but its limited water solubility hampers its end-use applications. In this work, at first bagasse soda lignin extracted form black liquor with lignoboost process and was modified with sodium sulfite under three different treatment conditions (75°C , 6 h and 90 °C , 6 h and 90 °C , 4 h) . The structure changes by using FTIR method and molecular weight by SEC, thermal behavior by TGA and elemental analysis of the product by CHNS were assessed. The results showed the sulfonated lignins are different from unmodified lignin in the amount of sulfonate group and have more sulfonate groups. Also the molecular weight, Solubility and thermal behavior in sulfonated lignins increased due to sulfonate group compared to unmodified lignin.

Conversion of agricultural wastes to valuable products is one of the sustainable method to prevent air pollution thet arises from biomass open burning. One of these new and valuable products are lignocellulosic aerogels, which due to their superior characteristics, such porous structure and large surface area can be used for removal of various pollutants such as dye. In this study, lignocellulosic aerogel obtained from rice straw were used to remove the Acid Orange 7 (AO7) from water and the effect of absorption process parameters on adsorption were investigated. The results demonstrated that the efficiency of adsorption greatly influenced by solution pH and temperature. For various concentrations of dye, the equilibrium was reached at 120 minutes. Isotherm data were well adapted to the Langmuir model and maximum adsorption capacity estimated from linear Langmuir was 52.1 mg/g that was approximately twice of the rice straw adsorption capacity. The kinetics results well interpreted by pseudo second order mode, indicating chemisorption as the rate-limiting step which correspond to the interactions between the active sites of aerogel surface and the functional groups of dyes.

Rice straw rice is one of the most important lignocellulose wastes in Iran and the world. In this research, rice straw as renewable lignocellulosic materials were used to produce nano-structural lignocellulosic aerogel. For this purpose, rice straw powder was first pre-treated in sodium hydroxide aqueous alkali solution and resulting gel form mixture was transformed into physically bonded lignocellulosic porous and ultra-lightweight aerogel through consecutive processes including freezing-thawing, solvent exchange and freeze-drying. The product properties including apparent density and total porosity were determined, and other physical and chemical properties were evaluated by SEM, FTIR, XRD, nitrogen absorption (BET) and DSC methods. The results showed that a significant amount of the rice straw compounds dissolved in aqueous alkali solution and removed during the subsequent stages of aerogel production. The resulting aerogel showed a nano dimensional structure composed of particles and interconnected nanofibers, which had a great chemical and physical difference from the original rice straw.

In this study, the alkaline pre-extraction followed with soda and monoethanolamine pulping of barley straw was investigated. The pre-extraction stage with removal of 34percent hemicelluloses due to highest yield was selected as optimum treatment. The results of pulping show that pre-extraction stage resulted in decrease of yield in both pulping processes meanwhile only in soda process the kappa number was influenced with pre-extraction stage. Tensile and burst indices of pulps drop because of pre-extraction stage. Unlike of these indices, the tear index of soda pulp from pre-extracted barley straw has been increased. The brightness of soda pulp from pre-extracted barley straw is increased while the pre-extraction stage has no significant effect on brightness of monoethanolamine pulps. The opacity of pulps remains unchanged after pre-extraction.

According to the importance of urea formaldehyde resin in plywood industry and to replace a suitable filler for this resin with wheat flour (common filler), lignin drived from three black liquors including alkaline sulfite-AQ, soda-AQ and Kraft evaluated as filler-extender for urea formaldehyde resin in the plywood manufacture. For this reason any of the four types of lignins were used at 0, 10, 20 and 30% dry weight of resin.After that, the physical and mechanical properties of samples including thickness swelling after 2 and 24 hours immersion in water, flexural strength and modulus of elasticity parallel and perpendicular to fiber the surface layer and shear strength were measured.The results of this study showed that increasing thelignin of alkali sulfite-anthraquinone and then kraft lignin, flexural strength and modulus of elasticity parallel to the fiber surface layer increased.Also, the bonding shear strength of the samples using three types of lignins increased. On the other hand, the use of these three types of lignin, improved the dimensional stability of the boards.The results show the superiority of lignin from alkaline sulfite anthraquinone process compared to other lignins to improving the mechanical properties of plywood.