Wood Modification and Wood Preservation
Hamid reza Zarey; Reza Hajihassani; seyedeh masoomeh; Kamyar Salehi
Abstract
Background and Objectives: Wood has some limitations in properties and applications due to its natural nature, which need to be modified. Wood modification is usually done with different aims and methods. One of the wood modification methods is thermal treatments in order to improvement of dimensional ...
Read More
Background and Objectives: Wood has some limitations in properties and applications due to its natural nature, which need to be modified. Wood modification is usually done with different aims and methods. One of the wood modification methods is thermal treatments in order to improvement of dimensional stability and biological resistance. But, it is surely affected on physical and mechanical properties of wood. Wood thermal modification in presence of oxygen causes the oxidation of its chemical structure which leads to decrement of physical and mechanical properties. Therefore, elimination of oxygen in thermal modification can reduce its destructive effects. In current study, the effect of thermo-oil process on the function of white rot fungus has been investigated. Moreover, the effect of this process on engineering properties of birch and pine wood species was evaluated.Methodology: In this study, two wood species of birch (Betula sp.) and pine (Pinus sp.) cut into the desired timbers. Heat treatment of the prepared timbers was carried out in a cylinder which equipped to the pressure and vacuum system. Also, industrial recycled oil was used for heat treatment of the timbers. The temperature and time treatment were considered 195 °C and 5 hours, respectively. At the end of the process, the used oil was drained into the oil storage tank and the timbers were removed from the cylinder after applying vacuum. In order to investigation of biological resistance as well as physical and mechanical properties (water absorption and swelling, density, mass loss, bending strength, compression strength parallel to the grain and impact strength) test specimens were prepared from the treated and control timbers based on the standard. The SPSS software was used for statistical analysis. The results were statistically analyzed based on a One-Way ANOVA method.Results: Results revealed that thermo-oil treatment can reduce the functionality of white rot fungus and also its efficiency on physical and mechanical properties of both wood species. Moreover, the results showed that this process improved the physical properties and reduced the mechanical properties, except compression strength parallel to the grain.Conclusion: Thermo-oil treatment at high temperature causes structural changes of wood and affects its physical and mechanical properties. Also, the structural changes caused by heat treatment can be an effective and inhibiting factor to functionality of white rot fungus on physical and mechanical properties of wood.
Composite wood products
Amir Nourbakhsh; Abolfazl Kargarfard; Ali Nourbakhsh; فرداد Golbabaei; Reza Hajihassani; Kamyar Salehi
Abstract
Background and objectives: The possibility of using agricultural lignocellulosic waste as a complementary raw material for the production of wood composite products can have a good economic justification. This will be possible if the manufactured product has the desired and standard quality, however, ...
Read More
Background and objectives: The possibility of using agricultural lignocellulosic waste as a complementary raw material for the production of wood composite products can have a good economic justification. This will be possible if the manufactured product has the desired and standard quality, however, considering that the type of wood material can have a determining effect on the physical and mechanical properties of the final product, therefore, conducting laboratory and research studies in order to recommend A raw material is essential for consumption in industry. The use of agricultural lignocellulosic waste in wood composite products industries has been the subject of various research activities in different parts of the world in recent years. In this research, in order to improve the mechanical and physical properties of wood-plastic, nanoclay particles have been used as reinforcements and corncob wastes have been used with poplar wood.Methodology: The amount of polypropylene and combination of materials were 60 wt% and 40 wt% respectively. The Nano-clay was added in three levels 0, 2 and 4 wt% and the amount of coupling agent was fixed and set to 2 wt% for all treatments. The control samples were made using poly propylene material. Results: The results showed that the tensile and flexural strengths were increased by the addition 25 corncob and 75 poplar wt% particles. For tensile and flexural modulus, adding 2 wt% of nano-clay led to an increase in strength and modulus but there was a decrease when 4 wt% nano-clay was used. The impact strength increased by adding nano-clayConclusion: According to the mechanical and physical properties of all the treatments, the samples which were made of 25 corncob and 75 poplar wt% particle with 2 wt% of Nano-clay had better results compared to other samples.
Wood Modification and Wood Preservation
Seyedeh Masoomeh Zamani; Reza Hajihassani; Kamyar Salehi
Abstract
AbstractThe purpose of this study was to evaluate effectiveness of brown rot fungus on ash (Fraxinus Sp.) and spruce (Picea Sp.) thermo-wood and also thermally modification on fungal functionality. In first step, prepared wood samples of both species were heat treated under 212 ºC for 3 hours. Afterwards, ...
Read More
AbstractThe purpose of this study was to evaluate effectiveness of brown rot fungus on ash (Fraxinus Sp.) and spruce (Picea Sp.) thermo-wood and also thermally modification on fungal functionality. In first step, prepared wood samples of both species were heat treated under 212 ºC for 3 hours. Afterwards, heat-treated and untreated wood specimens were exposed to brown rot fungus for 16 weeks based on EN 313 and the functionality of fungal destructive agent and also its effect on physical and mechanical properties were finally analyzed. The obtained results showed that the brown rot fungus has been more efficiency on untreated specimens in compared with thermo-wood in both two wood species and caused more destruction and mass loss. Moreover, the results revealed that some physical and mechanical properties include density, compression parallel to grain and impact strength of exposed heated specimens to brown rot fungus were more than unexposed heated specimens to this fungus. Evaluation of laccase activity which produced by brown rot fungus showed more its effect on controls than heat treated specimens in both wood species. Based on the results, thermally modification can generally causes improvement of biological resistance, reduction of some physical and mechanical properties as well as more stability of applied properties of ash and Picea wood which exposed to the brown rot fungus.
Saman Ghahri; Reza Hajihassani; Kamyar Salehi; Fardad Golbabaei
Abstract
In this study, the mechanical properties of kenaf cement composite were investigated using different amounts of kenaf particles (mixture of kenaf core and bark and kenaf core particles). Kenaf-cement composites were manufactured at different levels (10, 15 and 20%) of different kenaf particles. Also, ...
Read More
In this study, the mechanical properties of kenaf cement composite were investigated using different amounts of kenaf particles (mixture of kenaf core and bark and kenaf core particles). Kenaf-cement composites were manufactured at different levels (10, 15 and 20%) of different kenaf particles. Also, Portland cement and calcium chloride (as cement accelerating additive) were used in this research. Calcium chloride and water were mixed well and then kenaf particles were added to the mixture. At next stage, cement was added to the prepared mixture and all component were mixed well. Prepared mixture was molded to the wooden mold and kenaf cement composites were produced. The results obtained from mechanical evaluation of kenaf-cement composites showed the highest bending strength in 10% kenaf bark-cement composites. Also results revealed that highest modulus of elasticity of 10% kenaf core-cement products were obtained. The results of this research revealed the potential of kenaf particles as reinforcement in cement composite production.
Reza Hajihassani; Saman Ghahri; Kamyar Salehi; Fardad Golbabaei; seyedeh masoomeh
Abstract
Abstract In the current research, surface properties and failure modes of modified poplar wood (Populus deltoides) by hygrothermal treatment were evaluated. For this aim, the effect of variable factors included hygrothermal temperature (three levels: 130, 150 and 170°C) and holding time (two levels: ...
Read More
Abstract In the current research, surface properties and failure modes of modified poplar wood (Populus deltoides) by hygrothermal treatment were evaluated. For this aim, the effect of variable factors included hygrothermal temperature (three levels: 130, 150 and 170°C) and holding time (two levels: 20 and 40 minutes) on poplar wood specimens properties (contact angle and surface roughness) prior to and after planning were investigated. The surface characteristics and failure modes were evaluated for both treated and untreated wood specimens. The results revealed that surface roughness of poplar wood was enhanced due to the hygrothermal treatment in both states of before and after planning. It was also found that the hygrothermal treatment decreased contact angle of distilled water. The bending strength of specimens was reduced by hygrothermal treatment. According to the results, failure modes of hygrothermally treated specimens were simple and compression types in bending strength test. Keywords: Surface roughness, contact angle, bending strength, failure mode
Fardad Golbabaei; Reza Hajihassani; Kamyar Salehi; Asghar Tabei
Abstract
The aim of this study was to construct lightweight structures and reduce energy loss. The aim of this study was to produce cement wood or composite products by combining organic particles such as wood fibers and lignocellulosic materials with monolith. The investigated product consisted of cement wood ...
Read More
The aim of this study was to construct lightweight structures and reduce energy loss. The aim of this study was to produce cement wood or composite products by combining organic particles such as wood fibers and lignocellulosic materials with monolith. The investigated product consisted of cement wood made from scrap wood fibers and poplar wood particle thickness of 20 mm on both sides of the structure and 10 mm thick unolith in the middle of the structure. Products manufactured by Unolite Cement will have a combination of cement and Unolite properties. In this study, according to the studied variables including lignocellulosic materials and amount of additive (such as calcium chloride (Cacl) at two levels of 3 and 5%, the best specimens were prepared using 10% lignocellulosic materials. The thickness of the specimens was uniform at the two monolithic surfaces and all fabrication conditions such as discharge rate, press pressure, coalescence rate were assumed to be uniform and constant.In static bending experiment the mean maximum load force for ordinary brick failure was 3933.26N and the mean. The maximum load for breaking the cement stick was 389/78 N, which was approximately It has 10% resistance to ordinary brick but ordinary brick breaks abruptly when fractured, while the monolithic brick is gradually broken and the insulation properties due to the cellulosic fibers and the monolith in it are higher than the ordinary brick due to its low resistance to use. Recommended in partitions.
Composite wood products
Fardad Golbabaei; Kamyar Salehi; Reza Hajihassani
Abstract
In this study, the composition of bagasse composite was investigated using different amounts of bagasse particles. Bagasse and cement particles are manufactured at levels (5, 10 and 15%) and percentage of calcium chloride as cement accelerating additive at two levels (3 and 2%) based on cement dry weight. ...
Read More
In this study, the composition of bagasse composite was investigated using different amounts of bagasse particles. Bagasse and cement particles are manufactured at levels (5, 10 and 15%) and percentage of calcium chloride as cement accelerating additive at two levels (3 and 2%) based on cement dry weight. Then, the mixture was poured into a mold measuring 15 8 18 8 8 cm and the excess water was removed from the bottom of the mold and initially weighed 10 kg on the specimens. The specimens were removed from the mold after 48 hours and kept in a glass saturated room at 90% humidity for 14 days and then finally dried in a laboratory environment. The bending strength and physical properties tests were performed on the specimens. The results showed that bagasse particles had a significant effect on bending strength and other physical properties. The bending strength was highest in boards made with 10% bagasse particles.
Mechanical conversion of wood and wooden fittings
Fardad Golbabaei; Reza Hajihassani; Kamyar Salehi
Abstract
With full respect for the principles of linking wood and conservation project Eldar pine because having good mechanical properties and availability of a wood structure in the form of pavilions chose alcove to the octagon without internal column with computer software Sketch up of Alborz research center ...
Read More
With full respect for the principles of linking wood and conservation project Eldar pine because having good mechanical properties and availability of a wood structure in the form of pavilions chose alcove to the octagon without internal column with computer software Sketch up of Alborz research center with trees and landscaping of the complex was built. In making these structures all stages of the preparation of the wooden parts of drying are quite principled and dried in the open air during the six months were roof wood structure with the use of Eldar pine just Lambe was made in setting up the ceiling of solar connection on an octagonal timber wood using mortise and tenon mode and auxiliary metal was used. Sliding windows can be made to occupy less space. After completion of the period of three months to review the different pieces in different parts of the structure and measurements of physical densities, shrinkage and swelling and mechanical testing of hardness and impact resistance and protection review different parts of the fungal infection and decay structures was investigated. Since shortly after the beginning of the measure is going to change in the early stages of measuring statistically Darnbvdh but in the last stage of a decrease in density of about 5% and reduce the hardness of about 8% were signs of shrinkage and swelling in various parts of it to be seen.
Pulp and paper
Mohammad Ahmadi; Sahab Hejazi; Kamiar Salehi
Abstract
In this study, the effect of beating time on morphologic, physical and strength properties of soda and monoethanolamine pulps obtained from wheat straw was studied, in order to optimize the time for beating operation. Beating of the pulps was applied in different time by laboratory jokromill beater. ...
Read More
In this study, the effect of beating time on morphologic, physical and strength properties of soda and monoethanolamine pulps obtained from wheat straw was studied, in order to optimize the time for beating operation. Beating of the pulps was applied in different time by laboratory jokromill beater. The results showed that rising time of beating leads to increasing the freeness (SR) of pulps and monoethanolamine pulp reached to maximum amount of freeness (SR) in less time as compared to soda pulp. In addition, it is found that monoethanolamin pulp obtained the maximum amount of tensile index (91.3 N.m/g) after 30 min beating time and after that longer time of beating process had no significant effect on increasing the tensile index. About soda pulp it is observed that tensile index was increased significantly by rising the time of beating process and for this kind of pulp, maximum amount of tensile index (87.7N.m/g) was obtained in 50 min beating process. The highest burst index for soda pulp was 5 Kp.m2 which was obtained by 50 min beating process. About mono ethanolamine pulp burst index increased by rising time of beating Process and reached to its maximum amount (5.6 Kp.m2) and after that its amount decreased. Rising the time of beating process led to decreasing the tear index in both of kinds of pulp consist of monoethanolamin and soda pulp. The results showed that mono ethanolamine pulp had the higher yield and better beating ability in comparison with soda pulp which can be caused by better ability for carbohydrates and minerals retaining in monoethanolamin pulp.
Pulp and paper
Abbas Fakhryan roghani; Fardad Golbabaei; Hossein Hosseinkhani; Kamyar Salehi; Saeed Mahdavi; Sabrineh Mohsseni tavakoli
Abstract
In this reseach, chemical, anatomical and pulping properties of 12 years old Populus.triplo of adapting plan and quantity properties of this tree from karaj research station were investigated.The average of fiber length ,diameter ,lumen and thickness of cell wall 1.27 mm ,31.88 um, 23.54 um and 4.22 ...
Read More
In this reseach, chemical, anatomical and pulping properties of 12 years old Populus.triplo of adapting plan and quantity properties of this tree from karaj research station were investigated.The average of fiber length ,diameter ,lumen and thickness of cell wall 1.27 mm ,31.88 um, 23.54 um and 4.22 um and cellulose ,lignin , Ext. and ash %53.74 , %22.87 , %1.8 and %1.5 were measured respectively.The yield and kappa number of pulps between 41.152% - 48% and 18.06 – 25.28 were measured.In 14% and 18% effective alcoholli, tearh index 9.307 mNm²/gr and 10.147 mNm²/gr were obtained.
Pulp and paper
saeed mahdavi; masoudreza habibi; Abbas Fakhryan roghani; Kamyar Salehi
Abstract
Oil seed rape (Brassica napus) planting is increasing as the Iranian Ministry of Agriculture Jehad policy to provide supply of oil food in Iran. The objective of this study is utilization of rapeseed straw as a considerable raw material for paper industry whereas there is shortage of lignocellulosic ...
Read More
Oil seed rape (Brassica napus) planting is increasing as the Iranian Ministry of Agriculture Jehad policy to provide supply of oil food in Iran. The objective of this study is utilization of rapeseed straw as a considerable raw material for paper industry whereas there is shortage of lignocellulosic material in Iran. Sampling was carried out from two varieties of oil seed rape, Hiola 401 and PF, based on initial compatibility experiments and yield in Mazandaran province from Baye-colla research station. The results show that at least 4 ton/hect. oven dry rapeseed straws are available. There were significant differences between fiber width, lumen diameter, ash and extractive contents in two varieties. Rapeseed straw as a lignocellulosic material was achieved at 10 score according to the five characteristics consisting of phytology, fiber dimension, fiber yield, chemical components and appearance feature. This means more studies are necessary to make a final assessment.
Saeed Mahdavi; masoudreza habibi; Kamyar Salehi; Hossein Familian; kermanian hossein
Abstract
The common reed, P.australis, covers vast region in south of Iran. Specially, there is possibility of executing harvest in Hoor-Alazim canebrake as a reed natural provenance. It has good properties for papermaking in comparison of typical nonwood materials. Chips were pulped using typical kraft, soda ...
Read More
The common reed, P.australis, covers vast region in south of Iran. Specially, there is possibility of executing harvest in Hoor-Alazim canebrake as a reed natural provenance. It has good properties for papermaking in comparison of typical nonwood materials. Chips were pulped using typical kraft, soda and NSSC processes. Standard testing of pulp properties was made using TAPPI procedures. Pulps were beaten in a PFI mill to 400m.l.csf freeness level. Handsheets were made from the refined reed pulps for measuring strengths. Screen yield and kappa number of soda pulp were about similar to kraft pulp. NSSC pulp has lower kappa number than the soda at the equivalent screen yield. Energy consumption for beating from kraft, soda and NSSC pulps reduced respectively. Initial freeness of reed pulp was near to hardwood typical, thus good drainage and runnability on reed papermaking is expectable. The physical properties of reed handsheets were higher than newsprint and fluting pulps of Mazandaran Company. Overall, soda and NSSC reed pulps can be used in producing of newsprint and fluting papers based on the properties.
Physics and anatomy
Hossein Familian; Abdolrahman Hosseinzadeh; Mohammad hassan Asareh; Sayed mosa Sadeghi; Kamyar Salehi
Abstract
Ziziphus spina- christi of the family Rhamnaceae is widely distributed especially in the southern region of Iran and considered as one of the most drought - resistant sub species of the country. This investigation is the first attempt to study wood properties of this species, in order to contribute to ...
Read More
Ziziphus spina- christi of the family Rhamnaceae is widely distributed especially in the southern region of Iran and considered as one of the most drought - resistant sub species of the country. This investigation is the first attempt to study wood properties of this species, in order to contribute to a better understanding of it. It seems necessary to recognize the best utilization of this wood that are potentially available and easy to caltivate in Iran.The results of this study revealed that Ziziphus spina - christi is a diffuse - porous with pores round to oval, dense, hard and fine - textured wood. The length of vessel elements is medium, and the diameter relative high, few vessels per unit area and the type of perforation plates is simple. Parenchyma scanty paratracheal, vasicentric and rarely aliform. Libriform fibers length medium, thin to thick - walled. Rays 1-2 cells wide with medium length and not visible with nakedeye, crystals are common in most rays. In this species also percentages of cellulose and lignin are high but ash and extractive soluble in acetone content was found to be low.
Physics and anatomy
Kamyar Salehi; Abdolrahman Hosseinzadeh; Hossein Familian
Abstract
In order to investigate the possibility of utilizing cotton stem in cellulosic industries chemical, physical and anatomical properties of cotton stem (var. varamin) was investigated.Cotton wood fiber length, fiber diameter, lumen diameter and cell wall thickness was measured at 840 mm, 23.9mlm, ...
Read More
In order to investigate the possibility of utilizing cotton stem in cellulosic industries chemical, physical and anatomical properties of cotton stem (var. varamin) was investigated.Cotton wood fiber length, fiber diameter, lumen diameter and cell wall thickness was measured at 840 mm, 23.9mlm, 16/11mm, and 3/9mm respectively.Cotton stem oven-dry density, basic density, and air-dry density were measured at 0/44 gr./cm3, 0.4Ogr/cm3, and .42gr/cm3.Shrinkage and swelling was measured at 7.7 %, 8.3% and porosity was measured at 70.5%.Chemical composition was as follow: cellulose 52%, lignin 29.2%, ash 104% and extractives 6.8%.Anatomical features were as follow: Growth ring boundaries distinct or absent Wood diffuse-porous. Vessels in diagonal or radial pattern grouping:partly solitary partly in radial multiples of 2-4-6 or very small cluster Simple perforation plate. Intervesse pit alternate. Intervessel pit size: minute -< 4mm. Vestured pits absent. Vessel-ray pits with much reduced borders to apparently simple Helical Thickening absent. Mean tangential diameter of vessel lumina 50-100mm. Vessels per square millimeter 20-40 vessels. Mean vessel element length - < 350mm. Tyloses Gums & deposits absent. Fiber with simple to minutely bordered pits. Helical thickening in ground tissue fibers absent.Nonseptate fiber present. Fibers very thin walled. Rays with multi seriate portion as wide as uniseriate portion. Aggregate rays absent. Ray height> 1mm. Body ray cells procumbent with over 4 rows of upright And square marginal cells Ray per millimeter 4-12/mm.
Physics and anatomy
Hossein Familian; Abdolrahman Hosseinzadeh; Mohammad hassan Asareh; Saeed Mahdavi; Sayed mosa Sadeghi; Kamyar Salehi
Abstract
Ziziphus lotus of the family Rhamnaceae is distributed in the southern region of Iran and considered as one of drought - resistant tree species of the country. This investigation is the first attempt to study wood properties of this species, in order to contribute to a better understanding of it. The ...
Read More
Ziziphus lotus of the family Rhamnaceae is distributed in the southern region of Iran and considered as one of drought - resistant tree species of the country. This investigation is the first attempt to study wood properties of this species, in order to contribute to a better understanding of it. The results of this study revealed that Ziziphus lotus is a diffuse – porous with basic specific gravity medium and medium - textured wood. The length of vessel elements are medium, the diameter of vessel elements is small, porous with pores round to oval, intervessel pilting, opposite and intermediate, 20 vessels per square millimeter, simple perforation plates, vessel - ray pits similar to intervessel pits in size and shape and half bordered; Vascular tracheids present, there are rarely tyloses and Gums in vessels. Fibers with simple to minutely bordered pits, thin - to thick – walled and fiber lengths short; Parenchyma scanty paratracheal, vasicentric and rarely aliform; Ray uniseriate and sometimes biseriate, ray height is short, rays with procumbent, Square and upright cells mixed throughout the ray and one Prismatic crystals in chambered upright and square ray cells, rays 12 per mm, silica bodies in ray cells; There are 7-10 Schizogenous canals in pith.In this species also percentages of cellulose are high but ash and extractive soluble in acetone content was found to be low.
Physics and anatomy
Abdolrahman Hosseinzadeh; Hossein Familian; Kamyar Salehi; Abbas Fakhryan roghani; Fardad Golbabaei; Habibalah Arabtabar; Nayeralsadat Sadraei
Abstract
Eight-nineteen-year-old trees from Eucalyptus intertexta from Sarab bahman experimental Plantation located 160 Km. South west of Shiraz were selected randomly and fell two from each of the four blocks. Form each tree, 10 cm. thick cross-sectional discs at several different heights (3 meters intervals) ...
Read More
Eight-nineteen-year-old trees from Eucalyptus intertexta from Sarab bahman experimental Plantation located 160 Km. South west of Shiraz were selected randomly and fell two from each of the four blocks. Form each tree, 10 cm. thick cross-sectional discs at several different heights (3 meters intervals) were cut and together with remaining boles then transferred to the Alborz Research Center-Karaj for laboratory studies. The laboratory studies included determination of physical, anatomical and mechanical properties as well as chemical compositions of wood. The mechanical properties were evaluated on the ASTM methods for air-dry and green conditions. The following conclusions were drawn from this study:E. intertexta from one site in southern region of Iran has an average specific gravity of 0.86, fiber length of 0.71 mm, fiber diameter of 25.26 mm, lumen diameter of 4.04 mm, cell wall thickness 5.62 mm, cellulose content of 45.95; lignin 28.2; extractives soluble in alcohol - Banzen 4.28 and ash 0.62 percent.It was found that the mean values of modulus of rupture, modulus of elasticity and compression strength-parallel to grain tested at green condition were 74.21 MPa, 8454 MPa and 38.52 MPa and air-dried condition were 123.47 MPa, 14667 MPa and 77.99 MPa respectively. Data are also presented on other mechanical properties such as impact strength, nail withdrawal cleavage and etc.
Pulp and paper
Kamyar Salehi; Ahmad Jahan latibari; Abdolrahman Hosseinzadeh
Abstract
In order to investigate the possibility of utilizing bagasse in high yield pulping, CMP and CTMP pulp from bagasse was compared.APMP pulping process was also investigated. Bagasse fiber length, diameter, lumen diameter and cell wall thickness was measured at 1166mm, 19.63 mLm,7.47 mLm, and ...
Read More
In order to investigate the possibility of utilizing bagasse in high yield pulping, CMP and CTMP pulp from bagasse was compared.APMP pulping process was also investigated. Bagasse fiber length, diameter, lumen diameter and cell wall thickness was measured at 1166mm, 19.63 mLm,7.47 mLm, and 6.09 mLm respectively. Chemical composition was as follow: cellulose 553 %, lignin 20.5 %, ash 1.98% and extractive 2.9 %.The results and comparison of CMP and CTMP pulp are as follow: CTMP pulp yield was 3-4% higher than CMP pulp and the highest CTMP pulp at 80.7% was obtained at 15% NaOH application and 15 minutes chemical treatment time.Breaking length of both pulp was almost equal, but the burst index of CMP pulp was higher and the tear index was lower than CTMP. The highest breaking length of 3.85Kmwas obtained at 15% NaOH and 10 minutes, highest burst index of 4.81 KPa.m2/grat 20% NaOH and 20 minutes and highest tear index at 6.87 mN.m2/grat 15% NaOH and 15 minutes treatment time. Various treatments in APMP pulping reveald the following results: - Two stage pulping yield was almost 6% higher than one stage pulping and addition of H2O2 did not significant improve the yield.- The highest breaking length was related and two stage pulping. But addition of H2O2 in last stage and the lowest breaking length was related and two stage pulping with split application both NaOH and H202.- Even though two stage pulping with the addition of H2O2 in one stage produced highest burst index, but lowest burst index was with the CMP pulps.- Addition of DTPA produced highest brightness and opacity.
