IRANIAN JOURNAL OF WOOD AND PAPER INDUSTRIES
Year:2019 | Volume:10 | Issue:3 |Papers Count:12

This study was conducted to evaluate the stress carrying capacity of miter corner joints made with binder of biscuit under diagonal tension and compression loading. Corner joints with the Joint members from two species of beech (Fagus orientalis) and Fir (Abies alba), with 1 to 2 biscuits to size of 10 and 20 and with help adhesives of polyvinyl acetate (PVAc), polyurethane (PU) and urea formaldehyde (UF), they were made and tested. Since wooden pin joint is one of the most commonly included furniture joint, the test specimens were constructed using a pin and PVAc adhesive as a control for comparison with binder of biscuit. The results of analysis of variance showed that the independent effect of the species of Joint members, the size of biscuits, the number of binders and the type of adhesive in both compression and tensile loading is significant at 5% level. The results showed that the stress carrying capacity of the joints made with beech species is higher than that of fir species, and with increasing size and number of biscuits, the stress carrying capacity increases. The stress carrying capacity of the joints made with the polyurethane adhesive was also higher than those made joints with polyvinyl acetate and urea formaldehyde adhesives. The stress carrying capacity of the joints made under compression load was greater than the stress carrying capacity under the diagonal compression and tension load. The highest stress carrying capacity was observed in joints made with beech wood, two binders, biscuit size 20 and polyurethane glue, in both diagonal tension and compression loading.

In this study, effect of processed water was investigated on paper properties made from recycled fiber. Recycled pulp was supplied from Afrang Noor recycled paper factory and it was prepared from edge-cutted sheets of paper machine. Water also collected as two type of fresh water from plant tap water with conductivity of 213. 4 μ S/cm and process water from under the wire pit with conductivity of 4524 μ S/cm. Pulp after disintegrating by laboratory Valley beater drained on screen with 400 mesh and then used for making standard handsheet with 130± 5 g/m2 by two type of fresh water and process water. Water characterized with tests of Turbidity, TSS, MLVSS, TDS, Color and COD and the physical, mechanical and optical properties of papers were also carried out according to TAPPI standard. Results showed that by sedimentation for 24 h, significant changes was led in process water properties in which in sediment water TSS 80%, TDS 15%, Turbidity 53%, Color 8% and COD 15% decreased in comparison to initial sample. Also, using of process water for papermaking was led to loss of burst 30%, tensile 50%, tear 13% and bending stiffness 12% as well as loss in brightness to 17%. Hence, treatment of process water before papermaking is suggested as an essential step.

In this study, modulus of rupture (MOR) and modulus of elasticity (MOE) of glued-laminated timber (Glulam) made out of poplar (Populus alba) with galvanized steel nail, brad strip nail, coarse thread drywall screw for applying pressure were investigated and compared with those constructed with cold press. Amount of polyurethane adhesive was 300 g/m2. Thickness, width and span of 3-ply glulam specimens were 57, 80 and 640 mm, respectively. Static bending test was performed according to ASTM D 7341 by Instron testing machine. The results showed that the higher MOR and MOE were related to Glulam connected by 4 screws on 8×8 cm2 with adhesive (69. 3 MPa), and those connected by 2 galvanized steel nail with adhesive (6737. 7 MPa), respectively. The results also revealed that the lower MOR and MOE were both observed in Glulam connected by 2 brad strip nail without any adhesive (23. 9 and 1252. 7 MPa, respectively). The results showed that MOR and MOE of glulam were changed with the independent variation of number of fastener 3. 7 and ˂ 1%, respectively. The higher variation was related to independent effect of adhesive (130 and 317. 8% for MOR and MOE, respectively). Analysis of variance indicated that only the independent effect of adhesive application was only statistically significant at 95% confidence level. The comparison of MOR and MOE of Glulam made with two fasteners with those constructed by cold press showed that there was not significant difference between them. So, the use of galvanized steel nail, brad strip nail, coarse thread drywall screw for applying pressure to manufacture Glulam instead of cold press is possible and the best item was brad strip nail due to easy application and installation by pneumatic nailer and low cost.

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.

Due to the importance of the packaging industry and the increasing development of this industry, the importance of packaging and quality of all types of food products is important. Packaging should protectes the product from production to consumption against a variety of physical, chemical and biological factors to deliver a high quality and safe product to the customer. On the other hand, due to the importance of the environment and the emphasis on the formation and implementation of projects and processes with the aim of cleaning the environment, the packaging industry is also going towards using bio-based materials and less contaminating in the environment. Paper is one of the main packaging materials that can protect the product from damage without sacrificing its quality while being flexible, degradable, recyclable, and printable. Types of paper are used for this purpose. Recently, a new generation of paper with the name of the stone paper has entered the market that one of its uses is in packaging. In this paper, the mechanical and barrier properties of this type of paper are evaluated and compared with gloss paper, which is a high-quality type of cellulose fiber paper.

In this study, the effect of alum-dispersed rosin sequence has been examined on different properties of papers made from recycled fibers. Therefore, reverse sizing recycled fibers with 0. 5 consistency at pH 6. 5 was carried out by using 1 and 1. 5 % alum, and 1, 1. 5 and 2 % dispersed rosin, based on dry weight of pulp. Then, water absorption, optical and strength properties of papers with grammage (60± 3 g/m2) were evaluated. Based on the results, to reduce the water absorption of papers, 1 % of both alum and dispersed rosin is required to achieve appropriate level of sizing. As a result, the water absorption of papers declined from 174± 7. 4 g/m2 to 36± 0. 4 g/m2, and the contact angle of water droplet with paper surface increased from 31. 2 degree to 118. 1 degree. Moreover, concurrent to the hydrophobicity of fibers surface formed by rosin molecules and its repellency impact of inter-fiber bonding, alum imparts an improvement of bonds in paper network owing to the neutralization of anionic trash and retention of cellulose fines. Paper opacity has been increased due to the development of filler retaining in fibrous web of paper.

The purpose of this study is to fabricate air filters with various concentrations of cellulose nanofibres (CNFs) in order to evaluate its ability in the process of adsorbing (to adsorb) carbon dioxide (CO2). In this study, we make use of freezing drying method for making filters with three different concentrations (1, 1. 5 and 2%). SEM results show that increasing the concentration of CNFs increase the surface area but decreases the porosity and pore diameter. The results are also confirmed by the BET test. Also, mechanical properties and CO2 adsorption test were investigated. The results show that decreasing the concentration of CNFs decreases mechanical strength and carbon dioxide adsorption such that the minimum mechanical strength and adsorption of CO2 were for unmodified CNFs with 1% concentration and the highest adsorption of CO2 is associated with the modified 2% concentration CNFs.

In this study, the effect of various treatments with cellulose nanocrystals (NCC) and zinc oxide nanoparticles (ZnO) on the resistance and optical properties of the handmade papers were investigated. The nanomaterials with a specific condition (NCC 4%, 6%, and ZnO 3%) were added to the paper pulp during the papermaking. Cationic polyacrylamide used as a nanomaterials preservative in the papermaking process. The experiments results showed that the resistance properties (tensile index, tear index and burst index) of the treated papers are increased and the effect of NCC% increment was clearer in the enhancement of the resistance properties. Also, the brightness of the treated papers was increased after nanomaterials loading and the effect of ZnO was clearer because of its structural property. The opacity of the treated papers was increased at the binary composition of nanomaterials in comparison with the control sample, but in single addition of the nanomaterials to the papers, ZnO had better function than NCC.

Most of engineering applications require a series of properties which is not provided by a certain material. Therefore, composites production and utilization have extensively developed in various industries by materials combining. On the other hand, environmentally concerns compel environmentally friendly components in the composites manipulation. Then in this study, substitutability of imported synthesized Kevlar fiber by natural cellulosic fiber in epoxy resin matrix were investigated at presence and absence of nano bentonite. Dosages of 0. 25 and 0. 5 of fibers and 0. 1 and 0. 2 of nano bentonite were mixed into the epoxy resin and after bubble removal and complete curing, the composite panels were tested. The results showed that bubble removal and formation evenness mostly influenced the mechanical properties. So, tensile strength of 0. 5% Kevlar composites was lower than its 0. 25%. But opposite to the Kevlar, cellulose fiber increasing addition improved tensile strength and elasticity and rupture moduli properties, significantly. Consequently, 0. 5% cellulosic fiber composite revealed higher the properties with lesser surface area demolished by the ballistic impact, which all attributed to shorter length of cellulosic fiber (1. 8mm) compared to Kevlar (4. 8mm), resulted in better composite formation. But Kevlar composite energy absorption (54 J) was higher than cellulosic composite (50 J). Individual incorporation of Kevlar and cellulose fiber into epoxy resin and their combinations with nano bentonite drastically reduced the demolished surface area (up to 10 cm2) and matrix cracks propagation with symmetrically pinned hole compared to the solely epoxy panels (10 cm2).

In this study, the possibility of using γ-valerolactone as a green organic solvent for production of pulp from birch wood was investigated. The variables of cooking condition were different Liquor/Wood ratios (3 and 5), temperature (170 and 180° c), and time (60, 120 and 180 minutes) in the constant ratio of γ-valerolactone to water 50/50. The amount of yield, rejects, kappa number, viscosity and selectivity of different cooking conditions were determined. Based on the results, the L/W ratio 5, temperature 170 ° C and time 180 minutes was selected as the optimal treatment for γ-valerolactone cooking. After measuring the insoluble and soluble lignin in acid, the monosaccharides in the pulp were ascertained by high-performance anion-exchange chromatography (HPAEC-PAD) and the hydroxylmethyl furfural, furfural and organic acids in liquor were by high performance liquid chromatography (HPLC)and the mass balance of the pulp compositions produced by the γ-valerolactone-water process was calculated based on the dry weight of wood and pulp. The molar mass distribution of pulp was measured by gel permeation chromatography (GPC). The results of this research show the success in the production of pulp from birch wood by clean γ-valerolactone process.

Wood polymers made of vinyl monomers (such as styrene), due to the lack of penetration into the cell walls, have a slight decay resistance and requires supportive treatment. In this study, decay resistance and dimentional stability of poplar wood (Populus deltoids) treated with styrene and nano wollastonite was investigated. The vacuum-pressure method was used to impregnation of wood samples. The samples were treated with four diffrent formulations including 4% nano wollastonite, 75% styren, 4% nano wollastonite+75% styren (duble treatment), as well as mix of 4% nano wollastonite/75% styren (single treatment). The impregnation of wood with styrene monomer caused significant weight percent gain (more than 50%), while it was about 1% with nano-wollastonite. The volumetric swelling and the water absorption values of nano-wollastonite treated samples decresed compared to the controls. However, the maximum decrease in the volumetric swelling and the water absorption were observed with the styrenic wood polymer. The combination of nano-wellastonite with the styrene had no effect on these properties. Before leaching, the decay resistance of treated samples with nano-wollastonite and the styrene significantly increased. However, the effectiveness of treated samples with the nano-wollastonite was lost after leaching and their fungal resistance was similar to the control samples. The nano-wollastonite caused significant increase in the fungal resistance of styrenic wood polymers even after leaching, but the weight loss values were still significant. According to the results of this study, the use of eco-friendly products is recommended to increase the rotting resistance of styrenic wood polymers.

The aim of this study was to investigate the effect of using the protexin enzyme (percentage and repetition) as a probiotic agent on the properties of stored bagasse for pulp and paper production. For this purpose, the protexin was added at three concentrations of %0. 125, %0. 25 and %0. 5 based on oven-dry weight of bagasse and two treatment times: once (adding protoxin at the beginning and storage for six months) and twice (adding protexin at the beginning and after three months). Then, the treatment bagasse was evaluated for physical properties (weight loss and pH), and chemical compositions. After that, soda pulp was done under active alkali 17%, cooking temperature of 170 ° C and cooking time of 30 minutes. Finally, the properties of pulp and paper were measured and compared with green and control samples without treatment. Results showed that using of protexin enzyme with a concentration of 0. 5%, twice resulted in the highest conservation status of stored bagasse in terms of the quality of the raw material and pulp and paper properties. In general, the greater the concentration and frequency of using of the enzyme protexin in bagasse storage, a greater improvement in the quality of bagasse and pulp and paper properties can be achieved.