IRANIAN JOURNAL OF WOOD AND PAPER INDUSTRIES
Year:2020 | Volume:11 | Issue:1|Papers Count:13

In this study, flexural performance of cross-laminated timber (CLT) made out of poplar wood (Populus alba), Polyurethane adhesive and different mechanical connectors were investigated. Amount of adhesive was 300 g/m2. For manufacturing CLT panels, wood planks were air-dried, then four face-bonding surfaces of planks were planed (S4S). Thickness and width of planks were 19 and 100 mm, respectively. The thickness, width and span to depth ratio of Three-layered CLT specimens for bending test were 57, 80 mm and 12, respectively. Bending test was conducted by Instron 4486. The variables of this study were including different connectors (galvanized steel nail, strip brad nails (ST Nails) and coarse thread drywall screw), connector number (2 and 4), adhesive (with and without adhesive) and panel direction (major and minor direction). The results showed that the higher modulus of rupture (MOR) and modulus of elasticity (MOE) were related to major direction of CLT panels connected by 4 screws and adhesive as well the lower of them were related to minor direction of CLT panels connected by 2 ST nails and adhesive. The results also showed that MOR and MOE of CLT panels were changed about 71 and 16, 16 and 400, 1 and 10%, respectively with the change of shear connector, adhesive and number of connector. MOR and MOE in major direction of CLT panels were about 3 and 4 times higher than those in minor direction. The results revealed that MOR of CLT panels meet the specified requirements of ISO 16696-1 standard, however, MOE of them were not comparable with standard value. Hence, it was recommended to perform some comprehensive studies for reinforcing CLT panels made of poplar for increasing their MOE.

Acetate cellulose was used as cigarette filter, whose main function is to cool and purify the cigarette smoke. Nano cellulose as a sustainable bio material seems to have high potential as it is most common bio polymer in nature and is already available in micrometers to nanometers. In this research, cigarette filters were made of cellulose nano fibers with a concentration of 1%, 2% and 3% as well as mixture of each with 5% activated carbon. For this aim, the freezing of nano cellulose suspension in liquid nitrogen was used. After placing the filters in cigarettes, the samples were tested by the smoking machine and the carbon monoxide produced by burning cigarettes was directly measured by the machine and the amount of nicotine and tar were determined by gas chromatography test. The results of carbon monoxide and tar test showed that the use of filters made with cellulose nanofibers and activated carbon in comparison with acetate cellulose filters could significantly reduce these toxic and harmful substances (59. 6% and 77% respectively) however, nicotine of tested samples did not show a significant difference by control sample.

Precipitated calcium carbonate (PCC) as a mineral filler has many different industrial applications. The aim of the current study was to modify the PCC particles with cationic cornstarch and polyacrylamide to prepare modified PCC filler with improved hydrogen-bonding capability for papermaking industry. The modified samples were produced by simultaneous synthesis and modification procedures. The results showed that the cubic-like and nano-sized particles of precipitated calcium carbonate were successfully prepared from the commercial lime using carbonation of the slaked lime. The morphology and particle size of particles could be tailored using this method as illustrated by the FESEM results. XRD and FTIR data indicated that all the synthesized particles were prominently calcite polymorph with a slight amount of aragonite. Besides, the presence of organic substances in the structure of the modified samples was confirmed by FT-IR technique.

Along with the advancement of synthetic polymer industries, monomers are widely used for wood modification. Coupling agents play an important role in bonding non-polar monomers and wood hydroxyl groups. In the study of the effect of trimethoxysilyl polypropyl methacrylate (TMSPM) and triethoxy vinyl silane (TEVS) as coupling agents on the physical properties of poplar wood-polymer, the test specimens were divided into control and groups containing styrene (with and without silane coupling agents). Fourier-transform infrared spectroscopy (FTIR) results confirmed the presence of silane and monomer in the wood structure. Levels containing acrylate silane showed the carbonyl group, as well as the ketone carbonyl group of the wood structure. The absorption of monomer increased in samples containing vinyl silane more than acrylate ones. In spite of determining the highest absorption in vinyl silane, the highest weight gain was measured in the level that contained TMSPM, TEVS and styrene. Despite the higher reactivity of acrylate silane, the vinyl silane with a lower molecular weight resulted in the greater penetration of the compound into the wood structure which, in turn, resulted in a better polymerization with styrene at this level. The linkage of the modified cell wall with silane compounds to the polymer led to a decrease in weight gain and porosity and eventually improved dimensional stability, water repellency efficiency and anti-swelling efficiency of the product.

In the present research, the effect of surface densification on the treatability of Scots pine wood and micro-distribution of a saturation solution in the wood was studied. Densification was carried out at two compression ratios of 10 and 20% along the radial and tangential directions of wood with 12% EMC (equilibrium moisture content) at a pressure of 20 kg cm-2 and the temperature of 160 ° C for 3 min. In order to determine the treatability, the wood specimens were impregnated with 0. 5% Rhodamine B dye using alternating pressure method (APM) with an initial vacuum. Then, the treatability parameters were determined using ImageJ software and light microscopic studies. Results showed that the effect of densification on the treatability varies depending on the compression ratio and direction. The treatability of ray parenchyma cells increased by densification, whereas ray tracheids were not impregnated. The treatability of latewood was better compared with the earlywood, and the resin canals were also well treated.

Industrial wastewater is one of the major environmental pollutants. Discharge of the colorful industrial effluent into the receptive waters leads to eutrophication and has mutagenic and carcinogenic properties. Therefore, the aim of this study was to investigate the removal of methylene blue (MB) from aqueous solutions by tobacco residues activated carbon and ZnO nanocomposite (TRAC/ZnO). This is an experimental-lab study. The effect of various parameters on adsorbent performance was investigated. The non-linear isotherms and kinetics of adsorption were determined. The dye concentration was measured in wavelength of 664 nm by spectrophotometer. The results indicated that the removal rate of dye increased with increasing the contact time and dose of adsorbent pH but the removal rate decreased with increasing the initial concentration of dye. The maximum adsorption was achieved at initial concentration of 50 mg. L-1, pH=10, Ultrasonicated time of 8 min and adsorbent dosage of 0. 05 g/L-1. In addition, the dye removal with TRAC/ZnO nanocomposite was best fitted to Ferundlich isotherm (R2=0. 96) and pseudo second order kinetic (R2=0. 92). This study showed that the TRAC/ZnO nanocomposite is highly capable of removing MB dye from aqueous solutions in low contact time. Therefore, the TRAC/ZnO nanocomposite can be considered as an effective adsorbent in dye removal.

Food packaging as a protective layer is one of the most important factors that play a key role in providing healthy food. The aim of this study was to provide a novel paper packaging material by coating with a new dispersion barrier coating based on a mixture of soy protein isolate (SPI) and polyethylene wax (PE-wax) emulsion. For this purpose, mechanical properties, water absorption resistance and oxygen permeability of the specimens were investigated. The results indicated that although the tensile strength of coated paperboards decreased with the addition of PE-wax, there was no significant difference between the SPI-coated paperboards and 30% PE-wax coated ones, and 50% PE-wax coated paperboards showed only a decrease of 6% compared to SPI-coated ones. With increasing the share of PE-wax in the coating formulation, oxygen permeability increased in the coated paperboards but water absorption and water vapor permeability decreased dramatically.

The objective of this study was to investigate the production of natural-cement composite fiber using poplar, wheat straw and three types of additives. In this study, variables in making the boards were: usage percent of wheat straw (0, 15 and 30%) and fibers of poplar (70, 85 and 100%), and levels and types of additives (three levels and three types of additives, i. e. calcium chloride, magnesium chloride and calcium hydroxide, respectively). After producing test specimens, compressive strength (1, 3, 7 and 28 days), thickness swelling (TS), the modulus of rupture (MOR), and internal bond (IB), were evaluated. The highest and the lowest compressive strength (32. 5 and 7. 1 MPa) after 28 days were respectively for samples containing 7% calcium hydroxide and 3% magnesium chloride. Also, the boards with 30 percent wheat straw and 70 percent poplar wood fiber with the amount of 3% calcium chloride had a higher MOR compared to other boards. In general, the results suggest that calcium chloride additives with amount of 5% and the average value of 15% straw to 85% poplar is the appropriate amount for achieving acceptable values of IB and MOR. Due to its significance in the statistical analysis, the model presented by Response Surface Methodology provided a suitable and significant estimate to determine the application of the variables.

For appropriate use of fines and fiber fractions and how to apply them in paper structure, various multiply boards were made and the effect of fines removal, and their application in the middle layer, or only their removal from the top and bottom layers were investigated. The results showed that by eliminating the fine materials and producing a fine-free threeply board, the bending resistance and the bending resistance index were increased. However, studying the bulk property and the SEM images of the boards revealed that layers containing no fines were bulky and rough, meanwhile transferring the fines to the middle layer made it too dense. The ash content of fines indicated that significant percentage of the fines were comprised of fillers and minerals. Also it was shown that production of the board with a multi-ply structure did not negatively affect the physical and mechanical properties, but can help the process parameters.

The aim of this study is to investigate withdrawal resistance of T-shaped joints made of wooden biscuits. Biscuit joints which also called plate joints are usually constructed from compressed solid beech wood. Biscuits in the joints take up the moisture from water-based glues and resulted swelling at the slot leads to appropriate and strong joint. The variables of this study were the species of joint members including beech (Fagus orientalis) and fir (Abies alba), biscuit size of 10 and 20 (1 biscuits per joint) and type of glue including Polyvinyl acetate (PVAc), Polyurethane (PU) and Urea formaldehyde (UF). After constructing the specimens, withdrawal resistance test of biscuits was carried out. The results showed that the effects of independent variables namely, the species of joint members and the type of glue on the withdrawal resistance of biscuit joints was significant in the 1% level, but the independent effect of biscuit size was not significant. Also the results showed that the withdrawal resistance of the joints made with beech species was higher than fir. The polyurethane adhesive exhibited the best performance in comparison with the other adhesives. Finally, the best performance of the joints made with biscuit (beech, biscuit size 10 and polyurethane glue) was compared with the wooden dowel joints, which former showed the higher withdrawal resistance.

Biofuel briquettes are a type of solid biofuel produced for the purpose of producing electricity and heat. The present study investigates the improvement of the technical parameters of biofuel briquettes by micrometer and nanometer scale cellulosic binders. Biofuel briquettes from sugarcane bagasse were produced and compressed by a laboratory briquetting machine at a pressure of 150 MPa and a temperature of 100 OC. Cellulosic binders including recycled paper (OCC), recycled pulp, recycled fiber fines, and recycled nanolignocellulose (LCNF) were used in three percent ratios of 3, 6 and 9%. The results showed that nanolignocellulose and recycled fiber fines had more effect on the physical and mechanical properties of briquettes, as at the 9% level, the fiber fins had the highest compressive strength and thermal value as 26 N/mm and 22. 80 Mj/kg respectively And nanolignocellulose as 34 N/mm and 19. 85 Mj/kg respectively.

Poplar is one of the most widely used species in wood and paper industries, and there is a high demand for plantation of this species. Therefore, studying the factors affecting the biometric properties of fibers, anatomy, and physical properties of poplar wood is important. Reaction wood formation (tension wood) in woody plant like poplars is reaction against stress and environmental factors. Tension wood is a rich source of cellulose that can be used for some products including paper or biofuels. The aim of this study was to stimulate the formation of tension wood in two-yearsold white poplar (Populus alba) saplings by using alternate bending, nitrogen fertilization (NPK) and inducing gibberellin (G) hormone. Saplings were bended alternately for one month in one direction, and the next month in the opposite direction during the growing season, fertilizer application was applied twice i. e. at the beginning and in the middle of the growing season and gibberellin induction was applied once in the early growing season. Physical and anatomical characteristics of xylem were investigated after the end of the growing season. Studying of specimen transverse section after Safranin/Astrablue staining showed that in general, alternate bending treatments had more tension wood area in growth ring and ticker gelatinous layer than straight specimens. Alternate bending treatment with NPK+G had a higher wood density, more longitudinal shrinkage, less radial and tangential shrinkage, smaller and less frequent vessels, longer and ticker fibers. The results showed that this treatment was the most effective on the stimulation of the tension wood and the intensity of the formation of the tension wood in these specimens was higher.

In this study, the effect of Bane tree resin on the physical and mechanical properties of poplar wood was investigated. Wood samples were saturated by vacuum-pressure and immersion methods with concentrations of 1, 3, 6, 9, 12, and 15%. Physical and mechanical tests were done according to the related standards. The highest weight gain and retention of preservative material in vacuume-pressure treatment were 18. 52% and 71. 78 kg m-3 respectively at 15% concentration. The results showed that the use of Bane resin reduced water uptake and volumetric swelling of treated samples by 35 and 24. 5% over 168 h respectively in vacuum-pressure method. The compressive strength parallel to grain of the specimens treated with vacuum-pressure method did not change significantly. The hardness resistances of the samples saturated by vacuum-pressure method were increased by increasing of concentration up to 3% and then by increasing the preservative material concentration from 3 to 15% were reduced. Infrared spectroscopy results did not show any difference between the spectrums of Bane resin saturated sample and the control sample. Any new peak was not observed in infrared spectroscopy spectrum that indicates the Bane resin has not changed the main structure of the cell wall.