Iranian Journal of Wood and Paper Science Research
Year:2015 | Volume:30 | Issue:3|Papers Count:16

In this research, the microscopic properties of wood near the pith and bark of Dalbergia sissoo was investigated. Samples were selected from 3 trees of 10 years old from ShoshDanial area in Khozestan province. One disc was selected from each tree and from each disc 10 match stick size specimens were cut and used for fiber dimension measurements. Fibers were separated as defined by Franklin method. Microscopic segments of wood near the pith and bark were studied with light microscope. The results showed that the fiber length, fiber and lumen diameter, and cell wall thickness are significantly different between two regions and the measured values were increased from pith to bark. Ray widths and vessel diameters in wood near the pith and bark were 36.15, 132.98 and 31.82, 98.26 mm respectively and showed a significant difference at 5% significance level. The average number of vessels and the number of rays in wood near the pith and bark were 3.46, 7.20 and 3.54, 6.68 respectively. Also the average ray length in wood near the pith and bark were 130.86 and 132.05μm respectively but it didn’t show a significant difference at 5% significance level.

In this study, the effect of fish waste powder, polyethylene matrix, and coupling agent (MAPE) on physical and mechanical properties of wood-plastic composite were studied. For this purpose, poplar wood powder at 40% was mixed with 60% of HDPE. Fish waste at three levels (5, 10 and 15%), wood powder, HDPE and coupling agent at three levels (0, 2 and 4) was compounded at 180oC and rotating speed of 50 rpm, and then samples were made using injection molding. The mechanical properties; tensile and bending strength, bending and tensile modulus were measured according of ASTM standards. This result showed that increasing the amount of fish powder waste to 10%, increased bending strength while other strengths were reduced. All strengths values were increased by increasing in percentage of coupling agent to 4%.

The aim of this study was to investigate the mechanical properties of composite produced using recycled HDPE (high-density polyethylene) filled by furfural residue produced from bagasse. For this purpose, rHDPE was used at three levels 58, 68 and 78% and furfural residue as a filler was added at levels of 20, 30 and 40%. The grafted maleic anhydride with polyethylene (PE-g-MA) was used at constant amount of 2% as compatibilizer which was purchased from Arya polymer Co. The ingredients were mixed using two screw extruder and test pieces were made using injection molding method. Composite properties such as tensile strength, flexural and V-notch impact were measured according to ASTM test methods. The results showed that with increasing the filler content from 20 to 30% by weight, tensile modulus and flexural strength increased compared to the control and then reduced at 40 percent of filler. FTIR spectroscopy of the furfural residue and composite filled by 30% was carried out. Also, by increasing the filler content from 20 to 40% by weight, V-notch impact strength of composite decreased. FTIR spectroscopy revealed that the absorption bands of carbonyl groups (C=O) in 1750-1600 cm-1 wavelength was slightly increased if maleic anhydride compatibilizer was used. The maximum increases on mechanical properties of composite were achieved using 30% residual furfural as filler.

One of the major problems in wood gypsumboard production is fast hydration and thus reducing the physical and mechanical properties of the final product. In order to increase the curing time of gypsum, flourglue was used in wood gypsumboard production from canola wastes and poplar wood particles. To assess the setting time of gypsum, the Vicat Needle was used based on the ASTM C191. For this purpose, pure gypsum paste and the pastes with the ratios of 0, 0.1, 0.2, 0.3, 0.4 and 0.5 % flour glue to dried gypsum were settled in the mentioned device, then the setting time was determined. Thus amount 0.1% flour glue was selected for the manufacturing of wood gypsumboard. To evaluate the effects of flour glue andcanola straw wastes on the physical and mechanical properties wood gypsumboard, two levels of flour glue (0 and 0.1 % of the gypsum) and the canola straw wastes at 5 levels (0, 25, 50, 75 and 100% of the weight) of poplar particles wood was used. Density of boards was 0.9 g/cm3 and the thickness was 16 mm. The test specimens were prepared to measure the physical and mechanical properties according to EN standard. Results showed, flour glue addition increased the gypsum hydrationtime and improved all the physical and mechanical properties of wood gypsumboard. Also using of canola stem wastes increased water absorption and thickness swelling after 2 and 24 hours immersion. Flexural strength and modulus of elasticity of the boards were increased up to 25% canola wastes compared to poplar wood particles. However internal bond of the boards decreased by the increasing the amount of the canola wastes.

Strength properties and the yield of soda and soda-ethanol pulps produced using hornbeam, beech and poplar woods were investigated. Soda pulps were produced applying 20% active alkali and the soda-ethanol pulps were made using 10% active alkali and 50% ethanol. The pulping temperature was constant at 175oC and the soda pulping time was selected at 120 minutes and the soda-ethanol pulping times were 120 and 180 minutes. The highest accepted pulping yield at 58.54% was reached using soda pulping on poplar wood and the lowest yield at 49.29% was related to soda-ethanol pulp produced from beech wood applying 180 minutes pulping time. The accepted yield of soda-ethanol pulping was low, but the kappa numbers of these pulps were almost 20 units lower than soda pulps. The strength properties of soda-ethanol pulps were superior to soda pulps and the difference was statistically significant at 99% confidence level. The results of this study indicated that the delignification of soda-ethanol pulping process is faster than soda pulping from the selected hardwoods especially poplar wood.

In this research, kiwi tree residues chips from western Mazandaran (Tonkabon region) were randomly chosen and the kraft pulp was prepared with yield of 53% applying 105 minutes pulping time. The kraft linerboard handsheets were prepared from both kiwi and Chooka Mill kraft pulps (control sample), in pure form and mixed. Then, the optical and mechanical properties of the handsheets were measured according to TAPPI standard test methods. Results showed that the highest tear strength and cobb 60 and the lowest breaking length, burst and CMT values were measured from handsheets obtained from pure kiwi kraft pulp. The handsheet properties from mixed pulps were increased. In general, the highest values of breaking length, burst strength, tear strength, cobb 60, brightness and RCT were observed for the handsheets prepared from mixture of 10-30% kiwi kraft pulp and mill kraft pulp. The results also pointed out that the above mentioned strengths could be improved by adding 10-30% of kiwi kraft pulp to 30-70% mill kraft pulp, but similar values could not be reached using pure kiwi kraft pulp.

Bio-kraft pulp made from Hornbeam chips pre-treated by fungal (1, 2 and 3 weeks) was used for the investigation of its bleachability by DED sequence. Before and after of the each DED step, pulps and bleaching spent liquors was analyzed and then 60g/m2 standards handsheets were made from above pulps and optical properties of the handsheets were measured. Results showed that by increasing in chips pre-treatment time, lignin contents of pulps was reduced more extensively after DED steps. Also, pulp viscosity and DP were also reduced by increasing in pre-treatment time and hexenuronic acids were increased due to none selectivity of fungi. Fungal pre-treatment of chips did not significantly influence the brightness of unbleached pulps but due to softening the lignin structure, improved bleaching process as with increasing in pretreatment time brightness increased and opacity decreased. Generally, it seems that Hornbeam chips fungal pre-treatment has good efficiency on its pulp bleachability, although chemical consumption in bleaching increased up to 3 weeks pre-treatment.

The objective of this study was to produce natural fiber-plastic composite using soy straw powder as reinforcing component and to investigate the effect of nano-clay particles addition on the mechanical properties of the composite. Two levels of soy straw powder (35 and 45%) based on the weight of the composite, three levels of nano-clay (0.3 and 6%) based on the weight of the polypropylene as the matrix was used. Five percent Maleic Anhydride Ploy Propylene (MAPP) was added as the coupling agent. Composite compound was made and then the testing specimens were fabricated by injection molding and the mechanical strength were measured. The results were statistically analyzed using factorial experiment design. The results revealed that at higher dosage of the soy straw powder, the strength properties except impact strength values were reduced. At the higher addition of the nano-clay, the flexural strength and tensile strength were reduced and tensile and flexural modulus as well as the impact strength improved and the highest values were reached at 6% nano- clay addition. Also, at 3% nano-clay addition and 35% dosage of the soy straw powder, the thickness swelling and water absorption of composites were reduced.

In this study, the effect of chemical treatments of rice husk flour on physical and mechanical properties of rice husk flour/high density polyethylene composite was studied. Rice husk was milled and the particles passed through the 60 meshes sieve owas selected for treatment. Initially, dried rice husk flour was subjected to chemical treatment with acetic acid and then, was mixed with high density polyethylene powder at the weight ratio of 60% filler loading in an internal mixer. After milling of mixed material, samples of composites were made by injection molding method. Physical and mechanical properties of treated rice husk flour/high density polyethylene composites were compared to untreated composite and a composite including a PE-g-MA coupling agent (MAPE) that were produced by the same method. Dynamic Mechanical-Thermal Analyze (DMTA) of specimens in the temperature range of -50 to+150oC was taken and storage modulus and loss modulus were measured. FTIR spectra of chemical treatments of rice flour husks were also investigated to define the extent changes in the functional groups being studied. Results of FTIR indicated that the chemical treatment of rice husk led to a change of OH group absorbance on 3436 cm-1 and a peak in the region of 1741 cm1 related to functional group of C=O. Results also indicated that all of properties of composites containing treated rice husk flour with acetic acid were improved.

Brick has been the most common masonry in Iran building construction. Since the weight of the typical brick is usually high and causes heavy structures in the building, it makes the buildings vulnerable to earthquake forces. Although solid cement bricks and other building materials are durable, but the big disadvantage has been the heavy weight. Building solid brick density is usually 1.7 to 1.9 g/cm3 and thermal conductivity between 0.5oC to 0.75 kcal per hour in meters. Therefore, the structure of such bricks should be modified to reduce the density to 1.2 g/cm3 and improved the thermal conductivity to 0.25oC kcal per hour per meter. In order to reach a low specific weight and modify the thermal insulation properties of lightweight bricks, a porosity-causing additive such as sawdust is added to the raw materials of the brick. In this research sawdust was added to cement at 5, 10, 15 and 25% of the total weight of the brick and the properties of the final product was measured. Statistical analysis of the effect of various factors on the measured property showed that sawdust and cement brick made with 10 percent sawdust at the density of 1.260 g/cm3 and compression strength 1.2 MPa provided the best conditions for application in high load-bearing parts of the building. However, the brick containing 15% sawdust, which the density of 0.983 g/cm3, and compression strength of 0.85 MPa can be used in other parts of the building.

In this research, the effect of the alkaline precursors (soda and ammonia) as reagent for the deposition of zinc oxide nanoparticles in hydrothermal method on structure and physical properties of poplar wood was investigated. The samples of physical test were prepared with the dimensions of 2×2×2 cm3 according to ASTM-D4446-05, and at three conditions; control, Zncl2/NH3 and Zncl2/NaOH at 0.05M concentration and pH=10 were divided. Test samples were impregnated with salty precursor in the experimental cylinder using vacuum-pressure method, and in order to adjust the pH, either soda and ammonia weas added. Electron microscope images showed, changes in the type of precursor deposition caused different structure of ZnO nanoparticle. Retention of zinc oxide nanoparticles, density changes, water absorption, swelling and anti-swelling efficiency (ASE) were determined. Retention of zinc chloride precursor with ammonia and soda pH adjustment was determined as 4.43 and 1.71kg/m3 respectively. Water absorption increased during first hours of immersion, and then decreased. These treatments increased water absorption of wood. Lowest swelling and water absorption, and maximum ASE were measured in Zncl2/NH3 condition.

In this research, using professors and specialists opinion and studying the related literature, the effective factors on relations between companies (industrial suppliers) and suppliers were identified and the satisfaction concept in the supply chain was determined by investigating the factors such as trust‚ relation‚ cooperation‚ accordance with expectations‚ quality‚ cost and material provision time and production‚ order time‚ and delivery time until transferring to the final costumer. Statistical population of the research covered all managers of the companies and raw material suppliers which are active in the home wooden furniture industry of Tehran province. The data were collected using questionnaire. The research method is based on goal in applied form and according to implementation way and data collection is correlation description. We have used frequency distribution tables for findings description. In the inference step‚ we have used spearman correlation tests and path analysis with the help of SPSS16 software. The seven hypothesis are used which one of them was omitted in the analysis step and from six hypotheses which were used, one of them was not accepted. The research results showed that there are significant and strong relationships between trust‚ relation and cooperation and cost variables and industrial buyers’ satisfaction. In the case of the time delivery speed, although there is relationship but it isn’t high correlation.

The effect of poplar wood modification with maleic anhydride and methyl methacrylate on its mechanical properties and decay resistance is investigated. Samples of mechanical and biological resistance tests were prepared according to ASTM D143-94 and EN113 standards. Treatment conditions were divided into 4 groups; control, methyl methacrylate, maleic anhydride and combined maleic anhydride/methyl methacrylate. Samples were impregnated with maleic anhydride and methyl methacrylate monomer using vacuum-pressure method in a laboratory cylinder. Maleic anhydride treated samples were heated in the oven for either 4 and 24 hours at 150 and 103oC. For polymerization, methyl methacrylate monomer treated samples were heated in oven at 90oC for 24 hours, consequently at 103oC for the same time. Poly methyl methacrylate polymer coating was formed on the cell wall, causing 22.57% improvement in the lateral stability under pressure parallel to grain. Highest value in modulus of rupture, elasticity and hardness were measured in combined treatment condition providing 24.13, 47.13 and 45.53% improvement compared to control, respectively. Maleic anhydride in the presence of methyl methacrylate decreases polarity of the wood and creates good bonding between particle and the polymer, resulting in the cross linking formation and transmission of uniform tension that would lead to improved mechanical properties. Decay resistance was improved in all modifications, and weight loss declined from 80.4% in control to 4.29% in combined condition. Modification with maleic anhydride changes the wood composition and reduces moisture absorption potential and bulking of cell wall, and the presence of methyl methacrylate in the cell cavities causes physical barrier for the movement of fungi mycelium and moisture leading to improved decay resistance.

This research was conducted to investigate the effect of nano-wollastonite and the application of polyvinyl chloride and high density polyethylene polymers on the fire resistance of three layers particleboard made from pepper stalk and industrial wood particles. Urea-formaldehyde adhesive at 12% weight of the wood containing nanowollastonite (10%, based on dry mass of wood material) was used. Three types of the boards; mixture of industrial wood with pepper stalk particles, three layers board including the core layer from pepper stalk particles and the surface layer from industrial wood particles, the core layer from industrial wood particles and the surface layer from pepper stalk particles were made. Polymers were selected as high density polyethylene and polyvinyl chloride and nano-wollastonite in the two levels (with nano and without nano) were considered as variable factors. Test specimens for the examination of characteristics of fire resistance boards were made and fire resistance test including ignition timing (s), fusion time (s), weight loss (%) and carbonized area (mm2) for two duration of both 2 and 30 minutes in accordance with the ISO 11925 were determined. The results showed that the use of nano-wollastonite and polyvinyl chloride and high density polyethylene polymer improved fire resistance. In particular, high density polyethylene polymer showed better effect on the fire resistance of the boards. Three layers boards with industrial wood particles on the surface had a long ignition and fusion time. Moreover, percentage of weight loss and carbonized area in a three layerboards with pepper stalks particles on the surface were low.

Chitosan is known as a natural polymer which improves strength of paper. So, in this study chitosan absorption on modified kraft fibers and the increase on its efficiency were investigated. The effect of three levels (0%, 0.75% and 1.25%) of chitosanon on kraft fibers surfaces and 3% hydrogen peroxide dosage in different pH levels (5.5, 7 and 8.5) were studied. The results showed that chitosan had better performance at low dosages and alkaline conditions. Also fiber surface modification by hydrogen peroxide caused an increase of carboxyl groups and fibers anionic charge. Fibers anionic charge with the participation of chitosan formed a dual system. The apparent density increased from acidic pH to alkaline and the highest apparent density was reached in alkaline pH and 0.75 % of chitosan. Tensile strength index and burst strength index of paper were higher in alkaline pH and 0.75 % of chitosan. Whereas, chitosan and the surface modified fibers of kraft pulp did not significantly affected the tear index.