مجله صنایع چوب و کاغذ ایران
سال سیزدهم شماره 2 (تابستان 1401)

This study was performed in order to compare the independent and combined effects of four types of additives including cellulose nanofibers, cationic polyacrylamide, cationic starch, and imported long fiber pulp in the handsheet prepared from office waste paper. Independent treatments included the addition of 15% long fiber pulp, 3% cellulose nanofibers, 0.75% cationic starch and 0.07% cationic polyacrylamide. Combination treatments included firstly addition of 0.75% starch and then 3% cellulose nanofibers, and also 0.07% cationic polyacrylamide and 3% cellulose nanofibers. Handsheets with grammage of 60 g/m2 were made from seven furnishes and finally the physical, mechanical and microscopic structures of the handsheet were investigated. The results showed that addition of long fiber pulp, cationic starch, cationic polyacrylamide and cellulose nanofibers slightly reduced the density of handsheets compared with the control. The highest surface smoothness was achieved using combined treatments of cellulose nanofibers, which could improve the printability of the paper, but decreasing the air permeability and reducing the water drainage of the sheet by adding cellulose nanofibers could cause problems on paper and printing machines. Tensile, burst and tear indices of handsheets had the highest increase by the addition of 15% long fiber pulp, and then using 0.75% cationic starch improved the strength compared with other treatments. Electron microscopy images showed a relative reduction of porosity in the handsheets made from cellulose nanofibers, which could have negative effects on water drainage of recycled pulp.

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.

The purpose of this study is to determine and categorize indicators which are effective on selecting finish color type and spectrum and finishing method in the industry of home furniture. To achieve this purpose, by investigating conducted studies and interviewing with experts, factors which are effective on selecting the finish type and color spectrum and finishing method were divided to seven main indicators and 24 sub-indicators. The questionnaire was designed based on the Likert scale. In this study, the statistical population was the industrial units of production and furniture finishing in the different districts of Tehran province, and 53 questionnaires were randomly distributed among small workshops and large factories in proportion. The importance rate of the indicators and sub-indicators were determined by Friedman test and the software of SPSS after the questionnaires were received. The results indicate that the indicators of taste and the cultural climate of consumers, furniture use and economy, respectively, with the ranks of 5/38, 5/12 and 4/53 were highly important in selecting finish type and color spectrum as well as the method of home furniture finishing. The indicator of environment and safety and the indicator of production process with ranks of 1/98 and 2/78 had the least significance, respectively. Among the sub-indicators of taste and the cultural climate of consumers (as the most important indicator), the sub-indicators of beauty and the harmony of furniture color with service environment and customer satisfaction, respectively with ranks of 6/43, 6/03 and 6/02 were the most significant. The results gained from this study also indicate that most of finishing units do not pay attention to the issues of environment and personnel health, and the use of the new methods of finishing and eco-friendly finishes.

The purpose of this study was to investigate the effect of heat treatment on biological resistance and some physical and mechanical properties of paulownia wood (Paulownia fortunei). Thermo-wood specimens were prepared from paulownia wood based on thermo-D process. Heat-treated and untreated wood specimens were evaluated after exposing to brown rot fungus for 16 weeks. The laccase activity and its effect on mass loss and wood density were investigated. Moreover, some mechanical properties including impact strength and compression parallel to grain was measured. Evaluation of laccase activity showed more efficiency of this enzyme in untreated specimens in compared with thermo-wood and also it resulted in more mass loss. Therefore, heat treatment can improve biological resistance. The results also showed that heat treatment reduces density and impact strength of specimens, but improve compression parallel to the grain. Investigation of physical and mechanical properties of specimens exposed to brown rot fungus also showed that heat treatment reduced efficiency of this fungus on paulownia wood. So that, the value of mass loss, density and compression parallel to the grain in controls were more than thermo-wood. However, reduction of impact strength of thermo-wood was more than controls.

Furniture is a mixture of art and culture and a symbol of prosperity for Iranian families, and companies operating in this competitive industry need a comprehensive and long-term model for survival in the market. In this study, a strategic marketing model in the furniture industry is presented. The present study is an applied-developmental study in terms of purpose and in terms of method and time period of data collection, it is a cross-sectional survey research. Semi-structured interview and Likert scale questionnaire were used to collect data. The reliability of the questionnaire was assessed using combined reliability and Cronbach's alpha. Convergent validity was also used to validate the questionnaire. The statistical population of this research in the qualitative section includes experts in the furniture industry. Qualitative sampling continued in a targeted manner until theoretical saturation was achieved. The statistical community in a small part also includes managers and experts of the country's furniture industry. Using Cohen's effect size method, 140 people were calculated as samples. Random sampling method was used for sampling. In order to analyze the data in the qualitative part, the indicators of the strategic marketing model were identified using data-based theorizing method. The partial least squares method was used to validate and present the final model. Based on the results of qualitative analysis, 6 main categories, 18 sub-categories and 102 basic indicators were identified. Based on the paradigm model of the research, it was found that competitive forces constitute causal conditions. Strategic marketing is a central phenomenon. Marketing research provides the background, and corporate social responsibility is the intervening condition. Marketing strategy is a strategic factor that ultimately leads to functional marketing outcomes such as market share, market management and sales promotion.

The aim of this study was to investigate the withdrawal resistance of T-shaped joints, shear strength and bending moment capacity in the diagonal tensile loading of L-shaped joints made of wooden biscuits.The type of joint members including medium density fiberboard (MDF) and particleboard and the size of biscuits 10 and 20 (one biscuit per joint) were the variables of this study. After constructing the specimens using polyvinyl acetate (PVAc) adhesive, the withdrawal resistance test of T-shaped joints and shear strength and bending moment capacity tests of L-shaped joints were carried out. The results of analysis of variance showed that the effects of independent variables namely, the composite type (Joint members) and the biscuit size on the the withdrawal resistance was significant in the 95% confidence level, also the effects of these independent variables on the shear strength and the bending moment capacity in diagonal tensile loading of the biscuit joints, was significant in the 95% confidence level. According to the results, T-shaped joints made of wood biscuits of MDF members have a higher withdrawal resistance than joints made of particleboard members. the withdrawal resistance of T-shaped joints made of Biscuit size of 20 was higher than that of joints made of Biscuit size of 10.The Shear strength and bending moment capacity in diagonal tensile loading of L-shaped joints made of MDF members were higher than those made of particleboard members. The L-shaped joints made of biscuit size of 20 showed higher shear strength and bending moment capacity in tensile loading, than joints made of biscuit size of 10. generally, the highest amount of tensile and shear strengths and bending moment capacity in tensile loading were observed in the joints made of MDF and biscuit size of 20.

Borons and copper-based compounds are compounds used as pesticides and fungicides. One of the main problems of these compounds is that they easily be washed. Therefore, the main purpose of this study is to stabilize and reduce the leaching of protective materials using the encapsulation method. The encapsulation method of pesticides (boric acid and Bordeaux) was performed by natural chitosan polymer via electrospinning method and the compounds were used to treat poplar wood layers and make plywood. To evaluate the performance of the final product, physical tests (density, thickness swelling and water absorption), Fourier transform infrared spectroscopy and fungal tests were performed. The results showed that despite the low load of boric acid and pesticide, the performance of the layers was effective against fungal degradation. However, after severe leaching, their performance was reduced. The layers treated with the encapsulated pesticides retain their function as a pesticide against the fungus after washing. In general, the results showed that the technique of encapsulating pesticides can significantly reduce their leaching and on the other hand leads to maintain the function of pesticides.

Zein is one of the important proteins that can be used as a biodegradable coating in packaging cardboards. In this study, the effect of coated zein on the strength and barrier properties of liner cardboard was investigated. Zein was used in three levels of 50, 100, and 150 g/L in ethanol acid (95%) with two softener (glycerol) ratios of 0.5 and 1 (based on the dry weight of the zein) to coat cardboards. The results showed that the increasing of softener concentration in the coating solution had a positive effect on the air resistance and oil absorption but it had negative effect on water absorption. The basis weight, tensile and burst index of the coated samples were enhanced with increasing coating weight while the tear strength decreased. Moreover, the effect of increasing the softener concentration in the coating solution on the basis weight and tear index was positive but negative for tensile and burst indices and the results showed positive effect on the air and oil.

Microcrystalline cellulose is an important agent and additive in pharmaceutical, food, cosmetic and other industries. One of the important characteristics of microcrystalline cellulose powder is the degree of polymerization, which according to international standards, should be equal to or less than 350. In this research, using the Response Surface Methodology, the percentage of acid, reaction time, and input temperature are defined as the primary input variables affecting the degree of polymerization. The range of acid content to dry matter was set to be between 3 to 7%, temperature between 100 to 140 ° C and time between 120 to 150 minutes. Statistical analysis and mathematical modeling were performed to extract a nonlinear model (R2 =0.90) and then the optimum polymerization degree targeted to be 350. The acid percentage, temperature and time at the optimal degree of polymerization point were 3.34 %, 127 ° C, and 116 minutes, respectively. Using the optimal point data, the new experiment was carried out three times to validate the model. Then the average physical, mechanical and thermal properties of the produced microcrystalline cellulose were compared with the control sample. All physical and mechanical properties except for “ash” were in accordance with United States Pharmacopeia standards. The starting point of thermal degradation of the produced microcrystalline cellulose was 212 ° C compared to 226 ° C of the control sample, demonstrating improved thermal properties of the produced sample with the optimum values determined by the Design Expert software.

The study of wood characteristics of a plant species at different altitudes has always been considered by researchers in this field because altitude is one of the most important and influential options on climatic factors (temperature, rainfall, sunlight and relative humidity) in an area. The aim of this study is to obtain accurate knowledge of changes in biometric, physical and mechanical properties of Caucasian alder(Alnus subcordata) species in different altitudes of northern Iran. In this study, three habitat altitudes above sea level in Savadkuh region, Talar basin in Mazandaran province, with the names of Shalimak series (1400 meters height), Miyana series (1000 meters height) and Miyan Darreh series (500 meters height) were selected. From each height, three trees and a total of 9 trees were cut and from each tree, a disk with a thickness of 10 cm and a sample with a length of 150 cm from the diameter equal to the chest upwards were prepared. After initial preparation, the samples were measured according to the standard to evaluate different properties and were evaluated and analyzed. The results showed that altitude is one of the effective factors in changing the properties of the studied properties, so that with increasing altitude, the average fiber length, fiber diameter, cavity thickness and thickness of two walls decrease and the average specific gravity and volume shrinkage, Modulus of elasticity, modulus of rupture, compreession parallel to grain, cleavage, nail withdrawal resistance in cross-section and tangential, radial and cross-sectional hardness increased. The mechanical index of Caucasian alder wood in all three elevations was in the middle range,