IRANIAN JOURNAL OF WOOD AND PAPER INDUSTRIES
Year:2012 | Volume:2 | Issue:2|Papers Count:14

The aim of this study was to investigate the effective factors on surface quality of paulownia wood during machining by advanced computer numerical controlled (CNC) machine. For this aim paulownia logs were provided and were converted to proper sizes (2.5 x 10 x 15 cm) and then air dried. The Variable of this study were cutting speed (8.37 and 15.07 m/s), feeding rate (6 and 12 m/min), cutting depth (1 and 5 mm), cutting method (down and up-milling) and cutting pattern (tangential and radial). Roughness of cut specimens edge were evaluated by profilometer method according to ISO 13565 standard. For evaluation of surface quality, average roughness (Ra), maximum roughness (R max), valley roughness (Rv) and peak roughness (Rp) were used. Degrees of effectiveness of the parameters were evaluated by fractional factorial design as completely random design at confidence level of 95%. The result showed that cutting speed, cutting method and feed rate are influence factors on surface quality of machined specimens and their effects were significant. With increasing cutting speed and decreasing feeding rate the roughness decreased and surface quality improved. In up-milling cutting method, degree of roughness was higher and consequently surface quality was inferior. It is to be noted that cutting method in comparison to other factors had the high influence on surface quality. The rest variables did now have independent influence on surface quality at 95% Confidence level. This study for achieving the optimum surface quality recommends that cutting speed of 15.07 m/s, feeding rate of 6 m/min, cutting method of down-milling and cutting depth of 1 mm for tangential cross section.

In this research, the effect of impact modifier type on water diffusion coefficient, maximum water absorption and thickness swelling parameters of wood flour- recycled polypropylene composites were evaluated. For this purpose, a virgin PP was thermo-mechanically degraded by two times extrusion under controlled conditions in a twin-screw extruder at a rotor speed of 100 rpm and a temperature of 1900C. The virgin and recycled PP in 2nd stage, compatibilizer (0, 2 % w/w) and wood flour were compounded at 50% weight sawdust loading in a counter-rotating twin-screw extruder in presence different type of impact modifiers (0, 6 % w/w). Ethylene vinyl acetate (EVA), ethylene-propylene-diene monomer (EPDM) and acrylonitrile-butadiene-styrene (ABS) were used as impact modifiers. The analysis of diffusion mechanism and thickness swelling rate were done based on Fick’s theory and swelling model for wood flour- recycled polypropylene composites. The composites containing two times recycled PP exhibited lower moisture diffusion coefficients, swelling rate parameter, maximum water absorption, thickness swelling. Also results showed that moisture diffusion coefficients and thickness swelling parameters of composites containing EVA are lower than composites containing EPDM and ABS. The use of compatibilizer decreased the moisture diffusion coefficients and thickness swelling parameters of the wood flour- recycled polypropylene composites

Studying and rating of oncoming challenges of the wood and paper industries of the country can create a delicate attitude for policy makers and investors of these valuable industries. This study by the aim of identification and evaluation of wood and paper industries challenges with scientific and authentic method of likert spectra scale was done is 2010. Present challenges of wood and paper industries were detected by literature review and consulting with experts and academician and a number of manufacturing unites of wood and paper industries and query was designed. Intended data and statistics obtained from experts of wood and paper industries were compared and analyzed by likert scale spectra. The results showed that of 24 examined challenges, shortage of raw material, lake of long, compressive and applied prospective, existence of great gap between the university and industrial units and wearied and aged machinery are among the most important. Finally the identified challenges were submitted to the authorities for helping the economy of the country as well as causing the prosperity and budding of these industries.

To investigate the possibility of manufacturing medium-density fiberboard using corn stalk fibers, a mixture of corn stalk fibers and wood fibers in four weight levels of 0/100, 15/85, 70/30 and 45/55 and with press time of 5 and 7 minutes were used to manufacture sample boards. The results showed that an increase in amount of Maize Straw fibers leads to a decrease in MOR, MOE and IB levels in test specimens, whereas Thickness Swelling (TS) and Water Absorption (WA) increase after 2 and 24 hours of immersion in water. Furthermore, increasing press time resulted in an improvement of physical and mechanical properties of the specimens. According to statistical analyses, 15% of corn stalk fibers, with 7 minutes of press time, were founded as the optimum treatment in this study.

The effects of intercropping with alfalfa as well as initial tree spacing on physical variations of populous nigra betulifoliawood in radial and longitudinal axes are reported. Material was harvested from an agroforestry trial near Karaj city, Iran. Treatments included four initial-spacing between poplar trees intercropped with alfalfa as a nitrogen-fixing plant, as well as one control treatment (without alfalfa). Intercropping with alfalfa had a negative effect on wood density and shrinkage, but increasing initial spacing had a positive effect on them. Wood density, radial and tangential shrinkage decreased in longitudinal axis from bottom to top of tree trunk, whereas longitudinal shrinkage increased. Wood density and shrinkage in radial axis and at breast height level decreased from pith to bark; by 25% and 50% of tree this pattern was inverted for wood density. Statistical analysis showed the variation of shrinkage between treatments and in longitudinal axis was followed as density variation, but in radial axis density was not only effective factor on shrinkage.

This research presents an optimum framework for hardboard industry location selection in Mazandaran Province. Considering the existence of only two depreciated hardboard plants with very old technology in Iran, the establishments of new plants are vital. To materialize this goal, Mazandaran province enjoys priorities to other provinces based on its resources of raw lignocellulosic materials required for wood and paper industries. The model presented in this article uses AHP benefit/cost ratios. The results indicate that the criterion of ‘material and production’ with a weight of 0.327 and the sub-criterion of ‘reliability of supply’ with a weight of 0.146 have the highest priorities, and the city of Sari is the best alternative.

In this study, the possibility of using sunflower stalk for composite-board manufacturing was studied. Density of the boards were 0.45 g/cm3; variables included mixing ratios of sunflower stalk and industrial wood particles (100: 0, 70: 30, 50: 50, 30: 70 and 0: 100), type of resin at two levels of urea formaldehyde and isocyanate (PMDI) or polymeric diphenylmetane 4-4-Diisocyanate, and press-time of 5 and 7 minutes. Thickness swelling (TS) after 2&24 hours soaking in water, damping of sound (Damp), modulus of rupture (MOR), modulus of elasticity (MOE) and internal bonding (IB) of the boards were measured. The results showed that by increasing sunflower stalk particles, the amounts of TS 2&24, MOR, MOE and IB of laboratory panel were significantly increased. Isocyanate resin reduced thickness swelling after 2&24 hours soaking in water and increased damping of sound as well as modulus of elasticity. Also, urea formaldehyde resin improved modulus of rupture and internal bonding of panels. Press temperature had significant impact on the measured properties. Overall, using sunflower stalk particles up to 70 percent, isocyanate resin, and press time of 7 minutes, could result in producing boards with acceptable physical & mechanical properties which are suitable for interior uses.

In order to optimize the use of material non-forest resources, in this study the possibility of using the kenaf stalk fibers mixed with poplar fibers in producing medium density fiber board was considered. Variable factors such as density at two levels (0.55, 0.75 g /cm3) and the percentage incorporation of fiber (%50 poplar fibers, - %50 kenaf core fiber, %50 poplar fiber, -% 50 kenaf stalk fiber and %100 poplar fibers) were considered. Steaming time and temperature (175 °C, 10 min), press time and temperature (175 °C, 5 min), Pressing pressure (30 kg/cm3), fiber cake moisture (%12) and urea-formaldehyde resin with Concentration of %50 of the study factors were fixed. Results show that adding kenaf core fibers to the poplar fibers increases modulus of elasticity and water absorption but thickness swelling reduces. Increased density in board made with kenaf core has caused increase in bending strength, modulus of elasticity and internal bond strength and their water absorption and thickness swelling after 2 and 24 hours were competitive with poplar (MDF). On the other hand Populus fiber – kenaf stalk board mechanical and physical properties were competitive with (MDF) board made of %100 poplar fibers. Finally we can say that according to the statistical analysis, the best treatment in this study was using kenaf core fibers, in making poplar (MDF) with 0.75 g/cm3 density.

This research was investigation of steaming pretreatment on water and liquor absorbtion by wood particles. In this study, wood particles steamed at two different temperature (110 oC- 140 oC), and then were saturated in water and liquor at two different temperature (25 oC, 100 oC). Liquor was supplied with two different consistencies. That is, sodium hydroxide %9, sodium sulfite %6 and sodum hydroxide %18, sodium sulfite %12. Result of this research has shown that maximum absorbed water was %95.5. It was treated with steam of 140 oC for one hour, and minimum absorbed water was %68.9. It was treated with steam of 110 oC for half an hour. So, maximum of absorbed liquor was %108.64. It was treated with steam of 140oC for one hour. And least of absorbed liquor was %99.88. It was treated with steam of 110 oC for half hour. Moreover, maximum of water and liquor absorption for control samples were %94.98 and %107 respectively. However, they were less than treated samples.

This study was carried out to optimize of cationic starch use for improvement of the mechanical properties of mixed OCC & NSSC pulps. NSSC pulps were mixed with the OCC pulps by following weight ratios: 80/20, 70/30 and 60/40, respectively. Cationic starch was used in different charges of 0.5, 1.25, 2 and 3 %. The produced paper strength properties were measured according to Tappi standard. The results obtained from normalized equation showed that treatment of C4 (60% NSSC+40% OCC using 3% Cationic starch) is the best suitable samples. Also, by increasing the OCC proportion in mixed pulps, tensile, Tear, burst strengths increases, but Concora medium test (CMT) and Ring crush test (RCT) decreased. In general, by increasing of the cationic starch dosage, mechanical strengths has increased and its improved use had determined by 3% cationic starch.

Adequate conducting studies on site selection will have economic impact on performance of industrial firm; besides the effects of social, environmental, cultural and economic in their area.Also, the regional characteristics as key factors in determining where to locate the problem is that it creates incentives for public, private and cooperative sectors for investing on that place.Determining the effective indices in furniture industry to set sellers' view is the aim of this study that conducted in North Khorasan province, Iran in 2010. After reviewing literatures and interviews, the effecting factors were identified and classified into five main groups; "materials and products", "infrastructure", "mortal", "economic" and "rules and regulations". Value of weighted indices determined by getting comments from experienced furniture sellers as well as using Analytical Hierarchy Process (AHP) applied and flexible technique by Expert Choice software. The results showed that materials, distance to market, existing invertors indices with value-weighted 0.126, 0.114 and 0.099, respectively had highest priority.

In this research, the quality of recycled OCC pulp collected from different local companies was investigated compared with those of the local NSSC pulp from Mazandaran Wood and Paper Industries (MWPI). Also, the effect of different mixture from OCC pulp was evaluated with NSSC pulp. In addition, the effect of refining was studied on strength properties of OCC pulp and also combination of OCC and NSSC pulp. The results showed that, the NSSC pulp has the better fiber classification properties and higher strength properties compared to the recycled OCC pulp. Also, quality of OCC recycled pulps prepared from different companies was different because of the variety of raw material and production process. Refining of OCC pulp led to increase the mechanical properties of paper. The results of the handsheets and fluting papers prepared with various charges of OCC recycled pulp show that the majority of the mechanical properties were decreased and only tear strength were increased but difference between strength values were not shown significant. Totally, the results showed that by installation of an independent OCC mill in Mazandaran Wood and Paper Industries (MWPI) or completing present stock preparation with cleaning and suitable refining system, there is possibility to increase OCC consumption for fluting production with desirable quality.

In this research heat treatments of poplar wood in 2 different mediums (hot water and steam) in 185ºC were done in the sealed autoclave for 1 and 3 hours. Specimens were compared in density and mechanical properties. Density loss in hydrothermally treated wood was higher than hydrothermally treated samples. Mechanical properties (MOR and MOE) were decreased in both mediums, but strength loss was higher for hydrothermal treated samples. Compression strength parallel to grain didn’t show any significant change for hydrothermally treated wood but decreased in specimens with hydrothermal treatment. Poplar wood showed more decrease in toughness test with hydrothermal treatment. According to the results, hydrothermal treatment of poplar wood is recommended as a modification method with less negative effects on mechanical properties.