مجله صنایع چوب و کاغذ ایران
سال دوازدهم شماره 3 (پاییز 1400)

This study aims to use zeolite as a retarder of particleboards from sugarcane pulp (bagasse). In this study, mechanical properties, physical properties, fire resistance and CIE L * a * b * colorimetric test were investigated. The results of this study showed that the use of zeolite led to an increase in flexural strength, modulus of elasticity and impact resistance of the resulting particleboards. However, the internal adhesion of the resulting particleboard decreased. In addition, the use of zeolite as a flame retardant increased fire resistance. The results of physical properties also showed that zeolite reduced water absorption and thickness swelling in 2 hours of immersion. While water uptake and thickness swelling increased during 24 hours of immersion. The results showed that zeolite caused color change with increasing Δl and finally increased the whiteness and brightness of the surface of the samples. Zeolite reduced the combustion parameters, reduced the mass due to burn and the amount of carbonized surface and significantly increased the ignition time while drastically reduces flame retention and weight loss. In general, according to the measured parameters, the addition of zeolite can be considered as a slowing treatment.

The first purpose of this study is to investigate different methods of making viscous cellulose (in non-aqueous solvent) and strengthening tissue by cross-linking synthesis. The second goal is coupling with PVC. To coat viscovellulose on polyvinylchloride (PVC) surface in this study, instead of water, organic solvents as ethylenediamine and ethylene glycol were used to synthesize viscous cellulose. In the first method, gelatinization of cellulose was performed in ethylene glycol solvent and cellulose tissue was reinforced with ester ‎crosslink by additives such as phthalic ‎anhydride and polyvinyl alcohol. In the second method, cellulose was aminolyzed in ethylenediamine and an amide cross-link was formed by using terephthalic acid. In the third ‎method, cellulose ‎acetate tissue was reinforced with polyvinyl acetate and borax. Finally; it was rubberized with acetone solvent. In the final step, the viscose cellulose samples of each method were coated with a layer of PVC paste. To ‎compare the quality of coupling methods, the tensile test and moisture absorption test were used. Based on the obtained results, the first (ester crosslink) and second method (amide crosslink) had better tensile strength (with tensile device) and moisture absorption (with volatile meter) was more than the others. The tensile strength of the first method and its moisture absorption was more than other methods. Also, intrinsic viscosity [η] of viscocellulose: PVC paste (1:1ratio) showed that the third method ‎‎(cellulose acetate and polyvinyl acetate paste) has the highest homogeneity and adhesion ‎with PVC paste.  The advantage of these methods is that for the synthesis of viscous ‎cellulose, ethylene glycol solvent is used instead of water solvent and for activation energy, ‎a microwave beam is used instead of heater heat. The importance of microwave beams for this ‎research method is proved by the DSC method. ‎

Today, the use of credit cards has increased dramatically due to the advance in technology. The use of credit cards with public devices causes the transmission of pathogens. In this study, antibacterial papers were produced by biodegradable materials of lignocellulose such as nanocrystalline cellulose and carboxymethyl cellulose with iron oxide nanoparticles. Magnetic papers were produced with antibacterial properties and their performance was investigated on Escherichia coli and Staphylococcus aureus. The results of the magnetic test demonstrated that superparamagnetic properties in all samples. Nano magnetite with 25 (emu/g) showed the highest magnetic saturation as well as magnetic nanocrystalline cellulose with 15 (emu/g). The antibacterial action of the papers on the gram-negative bacteria Escherichia coli and gram-positive Staphylococcus aureus was appropriate and had prevented effect on bacteria. Moreover, the coated papers with magnetic nanocrystalline cellulose and carboxymethyl cellulose nanocomposites showed the highest bacterial inhibition area.

Nowadays, finding a catalyst with high quality and eco-friendly thermoset resins is very valuable. This study aimed to investigate the effect of maleated lignin-based polyacid (MA-PL) as a catalyst in urea-lignin-glyoxal (ULG) resin. For this reason, a phenolate reaction was done to increase the hydroxyl groups of lignin. Then the modified lignin was reacted with maleic anhydride to obtain polyacid based on maleated lignin. In the next step, different content of MA-PL catalyst (0, 1, 2, and 3 wt%) was added to ULG resin and prepared resins were used in particleboard panels production. Different properties of synthesized resins and panels were measured according to standard methods and were compared with those using ammonium chloride as the control sample. In addition, the thermal behavior of resin before and after adding catalyst was analyzed with Differential Scanning Calorimetry (DSC). Generally, the results of this research indicated that polyacids based lignin could be used as a suitable catalyst for ULG resin. Physical and mechanical test analysis indicated that the addition of catalyst from zero to 3 wt% continuously decrease pH and gelation time. DSC analysis showed that adding extra MA-PL reduces the curing temperature of resin compared with ammonium chloride. Based on the obtained results from manufactured panels, mechanical strength (MOE, MOR, and IB strength) and dimensional stability of the panels was improved by adding 3 wt% MA-PL.

This study aimed to investigate the biodegradability behavior and thermal properties of polycaprolactone / polylactic acid / nanocrystalline cellulose nanocomposites. Polycaprolactone and polylactic acid were dissolved in chloroform in ratios of 100/0, 95/5, 90/10, and 80/20%, and cellulose nanocrystals were added to the compounds at levels of 0, 0.5, 1, and 3%. Nanocomposites were prepared by solvent casting method. Then, their biodegradability behavior in the soil environment was investigated. The thermal properties of nanocomposites were investigated by thermogravimetric analysis and differential scanning calorimetry tests. Field emission scanning electron microscopy was also used for the microscopic study of nanocomposites. The results showed that with increasing cellulose nanocrystals to 1%, the mass loss of nanocomposites increased, but adding 3% of it led to a decrease in the mass loss of nanocomposites. With the increase of polylactic acid, up to 10%, the mass loss of the composites decreased, but the addition of 20% of it led to a decrease in the mass loss of the composites. The addition of cellulose nanocrystals to polycaprolactone increased its thermal resistance, but the addition of polylactic acid reduced this resistance. The results of scanning electron microscopy confirmed the degradation of nanocomposites in the soil.

Poplar is very important as a fast-growing species in the country's industry. So far, popular information such as level ٬ volume and harvest has been obtained using unscientific and weak methods. Due to the lack of comprehensive, up-to-date, and reliable information in the country about poplars, the study of identifying potential and actual facilities of poplar cultivation from different aspects such as area, volume, harvest, distribution, and species in four provinces (East Azerbaijan, Zanjan, Ardabil and Kermanshah) which have a great potential for poplar plantation was done. The cluster sampling method was used in two steps. The first stage was the collection of library information and semi-open interviews in the rural areas and the second stage was the field survey in the villages of these four provinces. The data obtained from the field survey were items such as poplar cultivation area, poplar stand volume, dominant species in each region, and volume estimation through volume and weight tables. The results show that the average annual harvest volume in the four studied provinces is 43156 cubic meters with the average error obtained based on the comparison between the two methods of interview and field method is 15%. The area of poplar in the four above-mentioned provinces (18039 hectares) is about 10% of the total area of ​​poplar in the country, which shows an 8% decrease in poplar in these four provinces compared with previous years.

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.

In recent years, the most important challenge for industries and companies producing wood-based composites was an increase in transportation costs due to increasing demand for a variety of wood materials. On the other hand, the use of lightweight elements in the manufacture of decoration and furniture has received much attention. The objective of this study was to produce and evaluate lightweight fiberboard using ethylene vinyl acetate (EVA). In this study, a mixture of industrial wood chips, two levels of resin (10 and 12%), and three levels of EVA as a foaming agent (1, 3, and 5%) were used to produce light fiberboard. In general, the application of EVA reduces the MOE, IB, and IBS compared with the control (without the use of EVA). However, this reduction can be improved by using 12% glue and 5% EVA. Statistical analysis showed that there was a significant improvement in the physical properties of the boards (reduced WA and TS) due to increased resin and EVA content.

In this study, the surface modification of cellulose fibers and its effect on the mechanical properties of fiber-cement composite was evaluated. The fiber modification was conducted through deposition of nano-silica at two levels 3 and 5 wt % (based on dry weight of cement) on the surface. The fibers and composites were characterized by emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectrum (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Also, mechanical in wet and dry state of cement fiber composites was investigated. FE-SEM and EDS analysis of the modified fibers showed that the nano-silica deposited on the fiber surface, as observed by the increase of the Si peak in the EDS measurement, which proved the effective modification of cellulose fibers with well dispersed nano-silica on the fiber surface. The reaction of the hydroxyl groups of the cellulose fibers and chemical bonding between cellulose and silica was formed after superficial modification examined by FT-IR analysis. The crystallinity index of the fibers was reduced 15%. The mechanical results showed that the presence of nano-silica treated fibers in the matrix increased the modulus of rupture (MOR) in wet and dry states.

This study aimed at the evaluation of wood machining parameters and surface quality upon using a water jet without abrasive material. Hence, wood species (beech, oak, and poplar), cutting velocity (200, 400 and, 600 m/s), and cutting direction (parallel and perpendicular to the grain) were chosen as variables. After cutting samples with water jet, the samples were scanned from edge and surface using a 1200 dpi scanner. For analyzing the depth of cut and kerf width, Image J software was used. The Surface quality was evaluated using a stylus profilometer, and the surface roughness parameters including Ra and, Rz were measured. The highest and lowest values of depth of cut and kerf width were measured for poplar and beech woods, respectively. According to the results, it can be stated that the cutting direction has a significant effect on the machining parameters so that the maximum depth of cut and the lowest kerf width was observed in the direction parallel to the grain. Also, the results showed that with increasing cutting velocity, the depth of cut increases, and kerf width decreases. The highest and lowest values of surface roughness parameters were observed in poplar (Rz=136/8µ), and beech (Rz=115/62µ) woods, respectively. Based on the results, it can be concluded that high-speed machining in woods with dense texture and parallel to grain can improve the surface quality in water jet cutting.

Microcrystalline cellulose is one of the important cellulose products widely used in pharmaceutical, food, cosmetic, and other industries, and Iran imports the whole Microcrystalline cellulose needs of its industries. In this study, bagasse was pulverized using the soda method, then bleached and residual impurities were removed to produce high-quality and pure cellulose microcrystals. The resulting bleached pulp was converted to alpha-cellulose using the cold soda method. Microcrystalline cellulose was produced using 3, 5 and 7% hydrochloric acid concentrations relative to dry matter. Hydrolysis was performed at 120 ° C for 150 minutes. Then, various experiments were conducted to determine the physical characteristics of cellulose microcrystals, FT-IR, XRD, TGA device analysis and were compared with high-quality control sample 1. The results showed that bagasse fibers are not significantly different from imported high-quality samples, and this method is quite promising to produce cellulose microcrystals. Crystalline percentage of the control was 39 while treatments 3, 5, and 7 were 90, 85, and 86, respectively. TGA results showed that the produced MCCs from bagasse don’t have a significant difference from the control sample (imported products). Considering no picks at 1735 and 1512, the produced MCCs are pure with no presence of hemi cellulose or lignin. Additionally, physical properties of the produced MCCs were complying with USP standards.