مجله تحقیقات علوم چوب و کاغذ ایران
سال سی و سوم شماره 4 (پیاپی 65، زمستان 1397)

High yield and chemi-Mechanical pulps are susceptible to oxidation-optical and thermal reactions. These reactions result discoloration and brightness reversion in pulps. In this research, chemi-mechanical pulps were selected randomly from Mazandaran pulp and paper mill and were bleached separately by P, H, PH and HP sequences and sheets with 60 gr/m2 gramage were prepared from these bleached pulps. All the prepared papers went through thermal aging, separately at 0, 12, 24, 36 and 48 hours at 1050C in oven, and their optical properties, including, their brightness, their a, b and L factor, α exponent, yellowness, opacity, K/S ratio, and PC number before and after thermal aging were measured and compared based on TAPPI standard. The results of this study showed that, during thermal aging from 0 to 48 h, paper optical properties such as brightness, L and a factor were decreased and b factor, yellowness, α, K/S ration and PC number were increased. As a result, bleaching by P and HP sequences had the highest amount of brightness and L factor and lowest amount of a and b factor, α exponent, yellowness, K/S ratio and PC number. Therefore, these bleaching sequences had important influences on brightness stability and decrease in paper brightness reversion and increasing their durability against thermal degradation.

Chemical and biological treatment of dye- containing wastewaters is difficult due to the low adsorption level and chemical stability of dyes. Activated carbon is usually used for adsorption of these materials, but because of high prices and restore problems, researchers trying to find available low-cost materials with high adsorption. In this study, bagasse was used for adsorption of Remzol Black B dye and its capability was examined. Variables were concentration, temperature, pH and contact time, and the degree of adsorption was examined in different situations. Then, adsorption isotherm according to Langmuir and Freundlich models was investigated. The results showed that the adsorption efficiency depends more on pH of solution and less on temperature of the solution. Maximum adsorption of Remzol Black B dye by bagasse occurred in the first 15 minutes of contact. The study of adsorption isotherm showed that both models are suitable for description of adsorption of Remzol Black B dye by bagasse. Maximum adsorption of Remzol Black B dye by bagasse was calculated as 7.51 mg/g. Results of this study showed that bagasse could be used as a low-cost bio adsorbent for the adsorption of Remzol Black B from aqueous solution.

To reuse recycled cellulosic fibers in paper production, contaminated particles and other impurities of the fibers can be greatly removed using a de-inking stage which is considered as a supplementary step in waste paper recycling technology. The effect of using ultrasonic pretreatment on the deinking of old newspapers was investigated utilizing the common conventional chemical method across this research work. Experimental design method was served to optimize the amount of ultrasonic bath temperature and sonication time. Therefore, 13 tests were designed using Response Surface Methodology (RSM) and Central Composite Design with Design Expert 7.0.0 Trial software. Ultrasonic bath temperature and sonication time at three different levels (1, 0 and 1+) and two axial points (α + and α-) were used as independent variables, and the optical and mechanical properties of handsheets were used as dependent variables. Response surfaces and contour plots were served to show the interaction between the independent variables and the response variable. ANOVA test showed that the quadratic model is the best model to explain the interaction among the studied variables. The predicted values of the obtained model had much conformity with the experimental results (R2=0.98). According to ANOVA results, it can be concluded that the effect of each of the variables on the optimal properties is significant and the ultrasonic time is the most effective factor on the response. According to the results, the proposed optimum conditions to achieve the highest amount of mechanical and optical properties (43.43) are the ultrasonic bath temperature 47 oC and the ultrasonic time of 31 min.

The present study was carried out with the aim of thermal analysis of furfurylated wood produced from beech (Fagus orientalis) and fir (Abies alba). In this regard, the specimens were saturated with two different levels of furfurylation in the form of low levels (14% fir and 20% beech) and high levels (38% fir and 65% beech), and compared with control samples. The results showed that changes in the TGA and DTA thermograms occur with an increase in the furfurylation level. In the first section of TGA graphs, thermal stability of the wood increased with furfurylation and its level change due to decreased water absorption and evaporation of gases during the process of furfurylation. But in the second and third regions, because of the replacement of furfuryl alcohol with lower thermal stability and flammability in the structure of wood and changes in the chemical structure of the wood, the thermal stability of wood polymers in both species decreased. The results of the analysis of DTA thermograms, in addition to confirming the findings from the TGA analysis, made clear the results of the impact of wood species on the thermal stability of wood polymers. Due to the difference in cellulose and hemicellulose and lignin in the structure of softwoods and hardwoods, the hemi-cellulose type in two species and the thermal stability difference of different implementation, wood polymers from two beech and fir are different in the variation of the surface under the curve of the DTA thermograms, the initial temperatures and peak temperatures.

The present study was conducted to inverstigate the effect of moisture content on adhesion strength of sealer half-polyester and sealer polyurethane on beech (Fagus orientalis) and hornbeam (Carpinus betulus) wood types of northern regions of Iran. PH values of beech and hornbeam was 5.51 and 5.19, respectively. Dried specimens were put in a climatization room to reach moisture contents of 7%, 11% and 15%. After the preparation stage, two layers of sealer were placed on the specimens using a spray. Next, polyurethane and half-polyester were applied to the specimens. The pull-off test was performed on the specimens according to the ASTM D 4541 Standard. The results showed that the most adhesion strength was that of the sealer polyurethane used on the beech wood type with the moisture content of 7 percent and the least adhesion strength belonged to the sealer half-polyester used on the hornbeam wood type with the moisture content of 15 percent. It was also observed that increasing moisture content caused a decrease in adhesion strength of both wood types.

Given the intense competition, rapid changes, new employee and customer requirements, and the modification of traditional management practices to optimize the capabilities of employees, today's organizations should work towards improving and institutionalizing entrepreneurial enterprise platforms. The purpose of this study was to investigate the status of enterprise entrepreneurship in public and private furniture companies and compare them with regard to the status of the entrepreneurial organization. To this end, various components of organizational entrepreneurship were conducted in order to identify strengths and weaknesses, and decision-makers could, taking into account the results, make appropriate decisions in order to promote organizational entrepreneurship. Regarding the nature of the subject and purpose of the research, this research is a descriptive-survey method in terms of data collection method. The data collection tool was a standardized Margarita Hill questionnaire (2003). The statistical population consisted of 963 human capital (606 individuals in private companies and 357 in government companies) in 14 furniture manufacturing companies (12 private companies and two public companies) in Tehran province, which was determined randomly and with proportional (public and private) assignments, and according to the Kregis-Morgan table, the sample size was determined. To determine the reliability of the questionnaires, Cronbach's alpha method was used in this research. Two independent samples were used to compare organizational entrepreneurship in two areas of the private and public sector. The average enterprise entrepreneurship rating in government companies was 1.612 and in private companies were 154.77. Standard deviations in public corporations were 78.88 and for private companies were 76.25. The results of the independent t-test showed that the comparison of the mean of organizational entrepreneurship between the two groups of public and private furniture companies at the level of 99% is significant.

The applications of renewable nanomaterial’s, such as cellulose nanofibers (CNFs), have recently been of great interest due to their unique properties, including high surface area, high aspect ratio, biodegradable, easy access and reactive hydroxyl groups on the surface. The purpose of this study was to fabricate refined air nano filters using phthalimide- modified CNFs. Because phthalimide contains amine groups that are needed to adsorb carbon dioxide. In this study, a freeze drying method was used for direct removal of water from pure CNFs gel and phthalimide -modified. Also, the properties of pure CNFs aerogels and phthalimide-modified (containing amine groups) were investigated to adsorption carbon dioxide. Modification of CNFs with phthalimide in 4% (v/v) acetic acid, with ratios of CNFs to phthalimide 1: 0, 1: 0.5, 1: 1 and 1: 1.5 wt %. Chemical properties and morphology of modified CNFs were investigated using various techniques including SEM, FTIR-ATR, XRD and TGA. Based on the results, the SEM test did not show any change in the size and structure of the modified CNFs. The presence of phthalimide was confirmed by the creation of new pitches NH2, C-N and ester 〖COO〗^- on modified CNFs using the ATR-FTIR spectroscopy test. Also, the results of TGA indicated that increasing the amount of phthalimide reduces the thermal stability, indicating the reactivity of the functional groups of phthalimide with CNFs. In addition, the highest carbon dioxide adsorption of 1.5% phthalimide was about 50%.

Understanding the market situation in order to obtain a suitable position in the new inter-national production system has particular importance. Therefore, the aim of this study was to determine and rank the effective indexes on the selection and purchase of paper in the card board production industries of the country. The expansion of the market and the multiplicity of industries have led to the importance of finding competitiveness as well as an accurate un-derstanding of their relative position in the market for many industries in order to make their economic and industrial policies compatible with their market conditions and relative position. Knowing this fact will help them improve their capabilities to improve their performance. Therefore, the purpose of this study was to determine and rank the effective measures on the choice and purchase of cardboard in the country's carton industry. The results of the ranking showed that among the 24 sub-indicators influencing the purchase and selection of cartons sheet in the paper board manufacturing industry,

In this study, in order to control the inhibitory compounds in the bio-refinery, bagasse pith was pretreated under acidic hydrolysis with dilute sulfuric acid 8%, 90 minutes at 120 ° C. Then, by using de-depleting methods of overliming, activated carbon and combining of both, removal of deterrent compounds from the above pretreatment hydrolyzates was performed. In the overliming, calcium hydroxide and sulfuric acid, in activated carbon method, activated carbon was used at three levels (0.5, 1.5 and 2.5%) and in the combined method of the combination of materials in the two previous methods became after acid treatments and each of the methods of insemination, the amount of recovered sugars and the values of the inhibitory compounds of furfural and hydroxymethylfurfural in the hydrolyzate were measured as two important indicators. The results showed that application of the above methods on hydrolyzate increased the yield of reduced sugars, so that the highest sugar yield (˃32%) was obtained after the independent method of overliming. In addition, active and combined carbon autonomous methods (overlimming and activated carbon) have an optimum activated carbon consumption of 2.5 and 1.5%, respectively. The qualitative study of the presence of inhibitory agents in hydrolyzates showed that furfural and hydroxymethylfurfural have maximum absorption at wavelengths of 276 and 282 nm. Also, an overliming with 2.5% activated carbon as the best method could eliminate up to 100% of inhibitory compounds. On the other hand, the autonomous method of overliming, with the removal of ˃90% of the inhibitory compounds, also has the highest sugar yield. Therefore, taking into account simultaneously the rate of sugar yield and the elimination of deterrent compounds, two independent alternatives of Overliming and Overliming with 2.5% active carbon could be proposed for the production of bioassays, such as bioethanol, xylitol, ... from the pith of bagasse.

The purpose of this study was to investigate the possibility of using tobacco stalk and industrial wood particles in particleboard industry as a waste material that is not consumed and discarded and has a low price, followed by a reduction in production costs from the way of choosing this raw material was of low value. For this purpose, the particles of tobacco stalk and industrial wood particles with different ratios of 0:100, 30:70 and 60:40, using the amount of adhesive used 12% and 14% (based on the dry weight of the wood chips) and the press time of 5 minutes for the construction of the board was considered. Physical and mechanical properties including thickness swelling after 2 and 24 hours immersion in water and bending strength (MOR), modulus of elasticity (MOE) and internal bonding (IB) were measured and all data were statistically analyzed. According to the results of this study, the increase in tobacco stalk particles resulted in increased thickness swelling after 2 and 24 hours immersion in water and reduced bending strength, modulus of elasticity and internal bonding, but all boards had a European standard (EN). Increasing the amount of resin also had a significant effect on all the properties of the boards and improved the properties. In a general conclusion and by comparing the properties of the boards produced with the European standard (EN), showed that using 60% tobacco stalk and 12% urea formaldehyde resin can be produced particleboard with the desired properties. This is a positive result of using tobacco stalk as a type of agricultural residue and, consequently, the prevention of environmental pollution caused by the burning of these compounds.

Carboxymethyl cellulose (CMC) is one of the important cellulose derivatives in industries, which is widely used as anti-caking agent, emulsifier, stabilizer, dispersing agent, thickener, and gelling agent. The main raw material of cellulose derivative is cellulose from wood and cotton linter. In this study, the cotton linter alpha-cellulose was used for producing CMC. Acidified sodium hydroxide process was applied to extract the cellulose from linter alpha-cellulose. Carboxymethyl cellulose was then prepared from cellulose. The optimization of reaction conditions was studied by using response surface methodology (RSM). The design experiment is Box-Behnken design consists of 3 factors (reaction time, % NaOH in mercerization process and mass ratio of monochloroacetic acid to cellulose in etherification process) with 3 levels. Based on it, the optimum values of independent variables are the reaction time of 54.23 min, NaOH concentration of 41.25 % and mass ratio of MCA to cellulose of 1.44 which the CMC had the DS of 0.656, the viscosity of 6634.76 cP. Fourier Transform Infrared spectra (FTIR) were used to characterize the product and starting Cotton Linter Alpha-cellulose.

The use of old corrugated container (OCC) is considered an effective solution by the paper industries in paper and paperboard productions bearing environmental and economic reasons. The strength properties of pulp made from recycled paper is weaker than the original pulp for various reasons, such as hornification. Therefore, various methods as adding strength enhancing materials and mechanical treatments are used to improve the quality of them. Because of little amount of production, many of the paper recyclers have limitation in investment of using mechanical treatments (refiners) in their production line. In this research, using cationic starch and cellulose nanofibers(CNF) was investigated as strengthen additives and as an alternative for mechanical refining in the paper and paperboard production from OCC. In this study, cationic starch in one level (2%) and cellulose nanofibers in 3 levels (2, 4, 6%) were used and compared to control (refined and non-refined) samples. Results showed that 2% CS and 4% CNF improved the tensile and burst indices same as or more than refining of pulp, while the pulp dewatering time and paper density were equal. Therefore, the aforementioned conditions are recommended as a substitute for refining in small units of waste paper recycling for paper and paperboard production.

This research investigates the cooking of monoethanolamine with a concentration of 50% and baking alkali sulphite with 18% alkalinity for making pulp from corn stalks. The combination of sodium hydroxide and sodium sulphite in rations of 70:30 as a measure of alkali sulphite and water and monoethanolamine with a ratio of 50:50 were selected as control treatments. The amount of deficiency was eliminated during all three processes due to the fact that it was not very minor and could not be weighed. Furthermore, the cooking conditions were chosen as variables: the process of alkali and soda sulphite was combined; time was 30:60:90 minutes at the three levels and the temperature was 125.145.165 degrees at the three levels; and the ratio of the baking fluid to the raw material (1 to 4) remained constant. The paper pulp produced with monovalent and 50% had the lowest amount of total efficiency (36.12) and kappa number (17.93). In alkaline sulphite treatment, it was observed that decreasing the temperature and increasing the time as variable factors, results in a decrease in the total return value and the kappa number likewise increases, so that the highest burst index (6.78) is related to baking with a temperature of 125 degrees and the total time would be 60 minutes.
The results of this study show that monoethanolamine/water (50:50) can be successfully used to make paper from corn stalks, and the characteristics of the pulp of manufactured paper, especially in terms of mechanical strength and kappa number, when mixed with water; and that it is superior to the process of alkali sulphite both as a combination and by itself