Pulp and paper
Ghasem Asadpour; Hadi Boroshkian; Hossein Resalaty
Abstract
The purpose of this study is to investigate the effect of pH on cellulase enzyme activity on the drainage and strength properties of OCC pulp. Recycled OCC pulp was pretreated with consistency 0.4 percent, in constant condition the temperature is 50˚C, duration 1 hour and range pH:4-4.5, 8-8.5 with ...
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The purpose of this study is to investigate the effect of pH on cellulase enzyme activity on the drainage and strength properties of OCC pulp. Recycled OCC pulp was pretreated with consistency 0.4 percent, in constant condition the temperature is 50˚C, duration 1 hour and range pH:4-4.5, 8-8.5 with cellulase enzyme at three levels 0.1, 0.3 and 0.5 percent (according to paper pulp dry weight). The results showed that pretreatment of cellulase enhances the freeness of pulp in comparison with the control samples, but by increasing the concentration of enzyme, the freeness of pulp was reduced in pH:4-4.5 the highest freeness is at the level of 0.1 percent and in pH:8-8.5 at the level of 0.3 percent. Also, papers were evaluated for resistance properties. The results showed that the increase in the use of cellulase enzyme has increased the tensile and burst strength index. As, in the alkaline pH, the effect of the cellulase enzyme on the increase of these strength was higher than the acid pH. The OCC pulp strength tear index, only in low levels of cellulase enzyme and in acidic pH, increased strength was observed, but with increasing enzyme consumption, there was a decrease in tear strength. Also, for strength to crushing, there was no specific trend regarding the amount of enzyme and pH on enzyme function.
Physics and anatomy
ahmad saraiyan; soodeh zhand
Abstract
In this study, the effect of boiling water pre-treatment on yield, optical, physical and mechanical properties of NSSC (Neutral Sulfite Semi Chemical) pulp from Zagroos wheat straw (Golestan province) was investigated. Chopped wheat straw was pretreated in boiling water for 30 minutes, water to straw ...
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In this study, the effect of boiling water pre-treatment on yield, optical, physical and mechanical properties of NSSC (Neutral Sulfite Semi Chemical) pulp from Zagroos wheat straw (Golestan province) was investigated. Chopped wheat straw was pretreated in boiling water for 30 minutes, water to straw ratio of 10:1. NSSC pulping was carried out at constant pulping conditions including liquor to straw ratio of 10:1, maximum pulping temperature of 160ºC and 30 minutes pulping time. In order to study the effect of NaOH on strength properties of paper, in some trails only Na2S03 were used. Pulping was followed by defibration in laboratory refiner to reach 380±25mlCSF freeness. Handsheets at 60gr/m² were made from each pulp. The strength properties were determined on the basis of TAPPI standard. Results show that pre-treatment imparted a significant increasing effect on the strength properties of papers such as tensile, burst, breaking length, stiffness and density, except RCT strength. Increasing the chemical charge specially NaOH improved the pulp freeness, yield and handsheet density but the handsheet thickness was reduced.
kezhal Moradyan Gilan; Mohammad Azad fallah; Amir abbas Shayghani akmal; Ali Abdolkhani
Abstract
This research was carried out with the aim of determining dielectric properties of bagasse unbleached soda pulp, long fiber kraft pulp and a mixture of both (20% kraft + 80% bagasse soda).The hand-sheets with 60 g/m2 basis weight were made after adjusting the freeness of pulps at levels of 200 ± ...
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This research was carried out with the aim of determining dielectric properties of bagasse unbleached soda pulp, long fiber kraft pulp and a mixture of both (20% kraft + 80% bagasse soda).The hand-sheets with 60 g/m2 basis weight were made after adjusting the freeness of pulps at levels of 200 ± 25 ml and 400± 25 ml and dried under mild condition around zero moisture content. Then the impregnation processes were carried out with mineral oil under vacuum at certain temperature. Finally the dielectric properties of impregnated papers including capacitance, insulation resistance, dielectric constant, and loss tangent were measured. The results showed that the refining give rise to enhance the dielectric properties in particular capacitance value. The dielectric properties of oil impregnated paper also increased. According to the preliminary results, unbleached soda bagasse pulp and its mixture with kraft pulp (20% Kraft -80% bagasse soda) found to be the suitable alternative with respect of dielectric applications for replacing kraft pulp, providing successful performance of the aging test.
Soodeh Zhand; Masieh Masoudifar; Ahmad Reza Saraeian; Ali Ghasemiyan
Abstract
In this study the effect of alkaline pretreatment with 1% NaOH on physical, optical and mechanical properties and refining of NSSC (Neutral Sulfite Semi Chemical) wheat straw pulp were investigated. The wheat straw (Zagros Sp.) was obtained from croplands Golestan province. Splinted wheat straw was pretreated ...
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In this study the effect of alkaline pretreatment with 1% NaOH on physical, optical and mechanical properties and refining of NSSC (Neutral Sulfite Semi Chemical) wheat straw pulp were investigated. The wheat straw (Zagros Sp.) was obtained from croplands Golestan province. Splinted wheat straw was pretreated with 1% NaOH(on the basis of OD weight) at 70 degrees for 30 minutes. The main pulping was performed at 160 ˚C with the fixed ratio of 5:1 Na2S03 and NaOH. After pulping defibration was done by lab-refiner to 380±25ml (CSF) and total yield and changes in Kappa was determined. Hand sheets of 60 gr. /m² were made on the basis of TAPPI standard and physical, optical and mechanical properties determined. The results show that alkaline pre-treatment has a significant effect in increasing of physical, optical and mechanical properties. Calculating primary freeness of pulps indicates that by increasing chemical compounds and NaOH, freeness decreases and that by increasing chemical compounds paper density increases, whereas yield, caliper and bulk decrease.
Pulp and paper
Reza Hosseinpoor; Ahmad Jahan - Latibari; Ajang Tajdini; Sayed javad Sapideh dam; Ramin Farnod
Abstract
The impact of chemical treatment variables including treatment time and temperature, chemical charge as well as pulp freeness on fiber quality of Colza stem chemi-mechanical pulp was studied using Fiber Quality Analyzer (FQA). Three treatment times (15, 30 and 45 minutes), two treatment temperatures ...
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The impact of chemical treatment variables including treatment time and temperature, chemical charge as well as pulp freeness on fiber quality of Colza stem chemi-mechanical pulp was studied using Fiber Quality Analyzer (FQA). Three treatment times (15, 30 and 45 minutes), two treatment temperatures (125 and 145 °C), two chemical charges (4% NaOH + 8% Na2SO3 and 8% NaOH +12% Na2SO3) as well as pulp refining were evaluated. The results revealed that at higher values of treatment variables, fiber average length was reduced and varied between 0.49 and 0.65 mm. However, the influence of pulp refining on fiber average length was not very pronounced. Pulps contained between 55 -63 % fines, which is on the high range and refining increased the fine content by 5%. Fiber coarseness varied between 10 and 41 mg/100m which was raised to 14 and 53 mg/100m upon refining. Even though refining did not alter fiber curl, but fiber kinks were increased.
Pulp and paper
Behzad Kord
Abstract
This study is for identifying of the effect of refining intensity on pulp and paper properties made from eucalyptuswood. For this purpose three normal eucalyptus camaldulensis spp trees were randomly cut down from Shastkolateh Experimental Forest located in Gorgan. From each tree, one disk ...
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This study is for identifying of the effect of refining intensity on pulp and paper properties made from eucalyptuswood. For this purpose three normal eucalyptus camaldulensis spp trees were randomly cut down from Shastkolateh Experimental Forest located in Gorgan. From each tree, one disk with 50cm thickness from breast height were selected for pulp making. Then disks converted to chips by chipper, and the chips were cooked by kraft process, the cooking conditions were as following effective alkali 20%, sulfidity 25%, tempreture 190 0C and Time 90min. After cooking and pulping process, the pulp refined with PFI Mill in 5 different intensity with 0 rpm, 500 rpm, 1500 rpm, 2500 rpm and 3500 revelutions. Then, papermaking and measuring the paper properties such as freeness, tensile strength, tear strength, burst strength and density were done. Then data were statisticaly analysed. The results indicated that, there are significant difference between pulp and paper properties made of eucalyptus camaldulensis spp wood with 5 different refining intensity in 95% confident level. As increasing of refining intensity and refining revolutions, freeness and tear strength of paper decreased but tensile strength, burst strength and density of paper incrased. However, the highest value of freeness and tear strength of paper related to refining intensity with 0rpm revelution (without refining) and highest value of tensile strength, burst strength and density of paper related to refining intensity with 3500rpm revelution
Pulp and paper
Mohammadreza Dehghani Firouzabadi; Afshin Tvasoli; Saeed Mahdavi
Abstract
We studied the possibility of replacing imported long fiber pulp (ILFP) with kenaf bast fiber soda pulp (KBFSP) to improve the quality of paper made with bagasse soda pulp (BSP). To do so, we produced BSP with kappa number 13.5 similar to that prepared by Pars Paper Mill. We also produced KBFSP with ...
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We studied the possibility of replacing imported long fiber pulp (ILFP) with kenaf bast fiber soda pulp (KBFSP) to improve the quality of paper made with bagasse soda pulp (BSP). To do so, we produced BSP with kappa number 13.5 similar to that prepared by Pars Paper Mill. We also produced KBFSP with kappa number 21.6 similar to the unbleached imported ILFP. The yield percent for BSP and KBFSP were respectively 48.9 and 55.6 %. The maximum pulping temperature was 165 °C; alkaline was 20% based on sodium hydroxide and ratio of liquor to dry weight of the raw material was 8:1. All the three pulps were beaten up to a freeness degree of 400 ml, CSF. Amounts of 0, 10, 20 and 30 percent ILFP and KBFSP were mixed with 100, 90, 80 and 70 percent BSP to produce hand sheets. In all cases of KBFSP mixing with BSP, the thickness of the generated hand sheets were higher than those produced through mixing ILFP with BSP while the density was lower. The difference in burst strength and breaking length of a mixture of 30% KBFSP with 70% BSP in the hand sheets were non-significant as compared with those of ILFP and BSP. Tear strength and opacity of mixing 30% KBFSP with 70% BSP were significantly higher than those of the ILFP and BSP with the same mixing ratio. We suggest that KBFSP provides a suitable replacement for ILFP to improve physical and strength properties of paper made with BSP.
Omid Ramazani; Ahmad Jahan latibari; Mohammad mehdi Faezipoor; Ali akbar Enayati; Sayed mehdi Manzor alajdad
Abstract
Apparent Density of paper is the most effective physical property which directly and indirectly affects most of the strength and optical properties of paper such as tensile strength, modulus of elasticity, light scattering coefficient as well as the bonded area between fibers. Since paper making variables ...
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Apparent Density of paper is the most effective physical property which directly and indirectly affects most of the strength and optical properties of paper such as tensile strength, modulus of elasticity, light scattering coefficient as well as the bonded area between fibers. Since paper making variables influences the apparent density of paper, in this study, the influence of OCC pulp freeness, and drying conditions are investigated. The influence of three freeness levels of 350,450, and 550 CSF, drying under strain and unstrained, drying temperatures of 100, 150, 200 C and drying pressure of 7 and 10 kg/cm2 are studied. The relationship between paper making variables and apparent density is developed. All measurements of apparent density were analyzed using Minitab 15 and regression model between independent variables was calculated. The results showed that both pulp freeness and drying temperature had the highest impact on apparent density and both factors increased the apparent density. The response of apparent density of the hand sheets dried at 200 ◦C varied considerably and was analyzed thoroughly. Higher pressure increased apparent density of the sheets. The combined effect of variables is also considered. The combined effect of pulp freeness and drying temperature caused lignin softening and delamination. However, the influence of increasing the drying pressure for unrefined and less refined pulp is not significant. Furthermore, for unstrained drying, the influence of freeness on apparent density was more than strained drying. Manufacturing of more desirable quality papers would be possible considering the obtained results and the effect of Apparent Density on paper strength properties.
