Pulp and paper
Arman Sadafi Ardejani; Esmaeil Rasooly Garmaroody; Pyam ghorbannezhad sorkhkolaei
Abstract
سابقه و هدف: الیاف سلولزی به دلیـل داشـتن گروههای اسیدی که در هنگام پخت شـیمیایی و رنگبـری خمیر ایجاد شده است، تا حدودی خاصـیت آنیـونی دارد. این گروههای اسیدی ممکن است ...
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سابقه و هدف: الیاف سلولزی به دلیـل داشـتن گروههای اسیدی که در هنگام پخت شـیمیایی و رنگبـری خمیر ایجاد شده است، تا حدودی خاصـیت آنیـونی دارد. این گروههای اسیدی ممکن است گروههای کربوکسیلیک (COOH) باشد که در مقایسه با گروههای هیدروکسیل موجود بر کربوهیدراتهای مواد لیگنوسلولزی از فعالیت و واکنش پذیری بیشتری برخوردار می باشند. چنانچه اگر بتوان تعداد این گروهها را بر روی سطح الیاف افزایش داد می توان در جهت بهبود مقاومت کاغذهای نهایی اقدام نمود. این تحقیق به منظور اصلاح ویژگیهای خمیرکاغذ کرافت چوکا با استفاده از روش اکسیداسیون اسیدی با کمک ماده شیمیایی پروکسید هیدروژن انجام شد. مواد و روشها: در این تحقیق از خمیرکاغذ کرافت، که از کارخانه چوکا تهیه شده بود، بعنوان ماده اولیه استفاده شد. در این راستا، ابتدا خمیرهای کرافت با استفاده از پروکسید هیدروژن به نسبت‌های 1، 3، 5 و 10 درصد در دمای 85 درجه ستنتیگراد، زمان 90 دقیقه، pH=4 و درصد خشکی 5/2 درصد مورد تیمار اکسیداسیون اسیدی قرار گرفتند. در پایان این مرحله، خمیرها با آب مقطر به طور کامل شستشو داده شده و برای مراحل بعدی مورد استفاده قرار گرفتند. سپس ویژگیهای ساختاری الیاف نظیر عدد کاپا، WRV، گروههای کربوکسیل، ویسکوزیته و آنالیز FT-IR مورد ارزیابی قرار گرفته و با نمونه شاهد کرافت کارخانه مقایسه شدند. جهت تجزیه و تحلیل آماری این پژوهش از نرم افزار SPSS استفاده شد و داده‌ها بصورت طرح کاملاً تصادفی با استفاده از تکنیک تجزیه واریانس مورد تجزیه و تحلیل آماری قرار گرفتند. مقایسه بین نمونه‌ها و تیمارهای مختلف بر اساس گروه بندی میانگین‌ها و به روش آزمون دانکن در سطح اطمینان 5/99 درصد صورت پذیرفت.نتایج: نتایج نشان داد که خمیرکاغذهای اکسید شده تا مصرف 3% پروکسید دارای کمترین کاپا، گروههای کربوکسیل و ویسکوزیته و بیشترین WRV بوده‌اند. افزایش مصرف پروکسید در غلظت بیشتر از 3% باعث افزایش عدد کاپا، گروههای کربوکسیل و ویسکوزیته گردیده است و در عوض با افت WRV مواجه گردیده اند. این تغییرات توسط ارزیابیهای FT-IR نیز تائید گردید. علت کاهش عدد کاپا تا غلظت 3% بدلیل خروج لیگنین از دیواره الیاف و دلیل افزایش آن در غلظتهای بیشتر از 3% پروکسید، احتمالا به ایجاد گروههای هگزورونیک اسیدی حین عملیات اکسیداسیون بر می گردد که معمولا اندازه گیری کاپا را با خطا مواجه می نمایند. بعلاوه خروج لیگنین باعث بهبود ویژگی WRV الیاف و بیشتر از آن باعث کاهش این ویژگی شده است. محتوای گروهای کربوکسیل برای هر دو شرایط قلیایی و اسیدی، کم و بیش بدون تغییر بنظر می رسند که این موضوع در کربن شماره 6 بیشتر آلدئیدها به گروههای کربوکسیل تبدیل شده ودر کربنهای 2 و 3 اکسیداسیون غالبا باعث تشکیل کتون ها می شود. از طرف دیگر به نظر می رسد که با افزایش گروههای کربوکسیل در تیمارهای بالای 3% منجر به افزایش وزن ملکولی سلولز شده که این امر باعث افزایش ویسکوزیته گردیده است.نتیجه گیری: ارزیابی نتایج نشان داد که اکسیداسیون پروکسید هیدروژن اسیدی باعث اصلاح و بهبود ویژگیهای خمیرکاغذ کرافت گردیده که اثرات آن بر روی ویژگیهای کاغذهای نهایی مثبت پیش بینی می شود. در این ارتباط، تیمارهای 1 و 3 درصد اکسیداسیون اسیدی با پروکسید هیدروژن برای تولید کاغذ مناسبتر به نظر می رسد.
Pulp and paper
Omid Esmailiey; Esmaeil Rasooly Garmaroody; Rahman Jafari petroudi
Abstract
Background and purpose: In the production of pulp, materials such as sodium hypochlorite, chlorine dioxide, ozone, hydrogen peroxide, etc. are used in the bleaching process. In addition, the above-mentioned materials can be used as oxidizing materials to increase the surface charge of fibers, can ...
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Background and purpose: In the production of pulp, materials such as sodium hypochlorite, chlorine dioxide, ozone, hydrogen peroxide, etc. are used in the bleaching process. In addition, the above-mentioned materials can be used as oxidizing materials to increase the surface charge of fibers, can help the paper to be more resistant. Therefore, this research was conducted to investigate the effect of fiber oxidation with hydrogen peroxide and sodium hypochlorite on the characteristics of NSSC and OCC pulps as fresh and recycled pulps, respectively.Materials and methods: The pulps required for this research, unbleached NSSC pulp and OCC pulp were obtained from Mazandaran wood and paper factory, and first, the percentage of consistency, initial freeness and brightness of the pulp were measured. Also, the required chemicals were all of industrial grade, hydrogen peroxide (in liquid form 52%) from Chlor Pars Tabriz Company and sodium hypochlorite (in liquid form 16.4%) from Kleran Semnan Company and sodium silicate from Bawand Shimi Qazvin Company, caustic (Liquid soda) with a purity of 47% for bleaching with peroxide was obtained from Arvand Abadan Petrochemical, and soda ash (solid soda) with a purity of 90% for bleaching with hypochlorite was obtained from Chloran Pars, Semnan. In order to control the destructive effects of transition metals, all pulps were treated with 0.2% DTPA, in 2% dryness conditions, time 30 minutes, temperature 90 degrees Celsius and pH=5.5-5, before bleaching. At the end of this step, the pulp is thoroughly washed with distilled water and used for the next steps. For the oxidation of both types of pulp, 3, 4, 5% hydrogen peroxide and sodium hypochlorite were used for oxidation of NSSC pulp using the above ratios (similar to peroxide) and for OCC pulp, 0.5, 1 and 1.5% hypochlorite ratios were used. Then the structural characteristics of the fibers such as pulp freeness, kappa number, WRV, viscosity, carboxyl groups were investigated and finally, the pulps were evaluated by FT-IR spectroscopy.Results: The results showed that with the increase in the consumption of hypochlorite, freeness increased in the oxidized NSSC pulps, but the trend of freeness decreased in the oxidized OCC pulp. This issue shows the situation regarding the use of peroxide. Also, the oxidation of pulp by sodium hypochlorite compared to peroxide has resulted in the release of more lignin, and in this sense, the effectiveness of OCC pulp (with 1.5% hypochlorite, equivalent to 56.68% Kappa loss) has been higher compared to NSSC pulp (with 5% hypochlorite, equivalent to 83.27% Kappa loss).The amount of water retention value in the pulp fibers in the NSSC pulp treatments has increased compared to the control pulp, and in the case of the OCC treatments, it has not changed significantly compared to the control treatment, and only in one case (OC-Na1) has a significant decrease. With the increase of peroxide consumption in the oxidation process of both types of NSSC and OCC pulp, despite the increase in viscosity, there is no significant difference between different consumption levels. In addition, with the increase in the level of hypochlorite consumption, a significant increase in the viscosity of the aforementioned pulps is observed So that the highest increase related to the sample using 5% hypochlorite for NSSC pulps was equal to 731.87 ml/g. The amount of carboxyl groups of pulps treated with peroxide increased in both types of NSSC and OCC pulps compared to the control sample so that the highest amount of carboxyl groups related to 5% treatment was equal to 0.0468 mmol/g for NSSC samples. The evaluation of FT-IR spectroscopy also shows that the oxidation treatment with peroxide and hypochlorite has increased the carboxyl groups on both types of pulp compared to the control samples.Conclusion: The effectiveness of hypochlorite compared to peroxide in the creation of carboxyl groups in both types of pulp was more, which seems that the increase of carboxyl groups on the cellulose chain occurred more on C6 by peroxide and more on C2 and C3 by hypochlorite. The oxidation process increases the viscosity of paper pulp by increasing the carboxyl groups and due to the creation of a higher molecular weight. In addition, the increase of carboxyl groups due to higher chemical activity has made them able to absorb higher water and thus higher WRV.
Jafar Ebrahimpour Kasmani; Ahmad Samariha; Saeed Mahdavi
Abstract
This study was carried out to compare the individual and combined effects of nanolignocelluloses (NLC), cationic polyacrylamide (CPAM), cationic starch (CS) and imported chemical long fiber (LF) in the manufacture of recycle liner and fluting paper for packaging. Individual treatments of OCC were included ...
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This study was carried out to compare the individual and combined effects of nanolignocelluloses (NLC), cationic polyacrylamide (CPAM), cationic starch (CS) and imported chemical long fiber (LF) in the manufacture of recycle liner and fluting paper for packaging. Individual treatments of OCC were included 15% LF, 6% NLC, 1.5% CS and 0.15% CPAM as addetives. Combined treatments were included 6% NLC and 1.5% CS, 6% NLC and 0.15% CPAM. Handsheets were made with grammage of 127 g/m2 by application the mentioned treatments. Finally, the physical, mechanical properties and microscopic structure of handsheet were investigated. The results showed that addition of LF and NLC caused the density of handsheets decreased compared to the control. The individual and combined treatments led to increasing the tensile and burst strength of handsheet. Also, the tear strength of handsheet increased compared to the control except for the combined treatment of NLC and CS. FE-SEM images showed pores relative reduction in handsheet that prepared from combination treatments. It showed negative effect on water drainage. The addition of 6% NLC and 0.15% CPAM to OCC pulp resulted in the highest crush strengths as RCT and CMT compared to the control. SEM micrographs showed relatively reduced pores in handsheets prepared from combined treatments, which could have negative effect on the dewatering of OCC pulp.
Pulp and paper
Noradin Nazaneghad; seid najeh Mosavi; Seid Majid Zabihzadeh
Abstract
Abstract The aim of this study is investigate the effect of Tapioca and Corn cationic starch on the mechanical characteristics of paper from old corrugated containers. The paper recycling decrease its properties and affected on the paper quality. For promoting these fibers may be effective the use of ...
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Abstract The aim of this study is investigate the effect of Tapioca and Corn cationic starch on the mechanical characteristics of paper from old corrugated containers. The paper recycling decrease its properties and affected on the paper quality. For promoting these fibers may be effective the use of different treatments. Cationic starch is effective treatment for recycled fibers Promotion. In this study, the cationic starch of Tapioca and Corn, each at three different levels 0.5, 1 and 1.5 % and comparison with samples (without cationic stretch). Hand sheets with a grammag of 120 g/m2 were made and their strength properties were measured. As well as, the absorption rates of two kinds of starch on the pulp were calculated using the Acid- Phenol method. The results indicated that the use of 1.5% of Tapioca starch and 1% Corn starch had an optimum effect in increasing the strength of the produced paper. Concerning the comparison of these different types of starch, the tapioca starch was more effective than the corn starch.
Sina Modirahmati; Ahmad Jahan Latibari; Amir Nourbakhsh; Mehran Roohnia; Mansor Minaei
Abstract
The impact of nanoclay addition on the properties of polypropylene/ OCC fibers/ nanoclay Composite was investigated. Composites were prepared using 67% polypropylene, 30% OCC fiber, 3% MAPP and three dosages (2.5, 5, 7.5% based on total weight of PP/OCC/MAPP) of nanoclay. Premix- ...
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The impact of nanoclay addition on the properties of polypropylene/ OCC fibers/ nanoclay Composite was investigated. Composites were prepared using 67% polypropylene, 30% OCC fiber, 3% MAPP and three dosages (2.5, 5, 7.5% based on total weight of PP/OCC/MAPP) of nanoclay. Premix- melting of nanoclay and polypropylene was used to add nanoclay to the composite mixture. Pre-mixed nanoclay/ polypropylene was melt-mixed with OCC fibers and MAPP and then test samples were made using this compound. The results revealed that addition of nanoclay to polypropylene/OCC fiber composite reduced flexural strength , tensile strength and notched Izod impact strength, but the flexural modulus and tensile modulus of final composite were improved significantly. The influence of nanoclay addition on flexural strength and tensile modulus of composite was statistically significant at 99% level whereas its effect on tensile strength was statistically significant at 95%. However, the effect of nanoclay on both flexural modulus of elasticity and impact strength was not statistically significant. The addition of nanoclay to the composite reduces the bonding between polypropylene and OCC fibers. In the case of notched Izod strength, nanoclay particles generated stress concentration point within the composite structure initiating easier failure. Water absorption after 2 and 24 hours immersion was reduced.
Sasan َAbangah; Ahmad Jahan Latibari; Seyad Javad Sepideh dam; Mehran Roohnia; Mohammad ali Hossein
Abstract
The influence of reinforcing fibers (old corrugated container fibers called OCC) and addition of foaming agents (Azodicarbinamide and sodium bicarbonate) on density, strength properties and dimensional stability of OCC fiber/polypropylene composite were investigated. Conten of reinforcing fibers constant ...
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The influence of reinforcing fibers (old corrugated container fibers called OCC) and addition of foaming agents (Azodicarbinamide and sodium bicarbonate) on density, strength properties and dimensional stability of OCC fiber/polypropylene composite were investigated. Conten of reinforcing fibers constant at 20% and the content of either foaming agent varied as 3, 5 and 7%. Strength properties including MOR, MOE, maximum tensile strength and modulus as well as izod impact strength were measured. Water absorption after 2 and 24 hours soaking in distilled water at 23±2 ºC were measured. Foaming agent decomposition caused some chemical residues in composite and the diffusion and penetration of polymer into the fibers structure led to increase in the density from 839.2 kg/m3 for pure polypropylene to 919.2 - 947.9kg/m3 for the composite, MOR and MOE also increased by the addition of foaming agent and the reinforcing fiber. The effect of 5 or 7% sodium bicarbonate was statistically significant and it improved the properties of the composite. Similar results were obtained for tensile strength and the modulus. Reinforcing fibers and foaming agent caused higher impact strength of the composite. Water absorption of the composites was higher than pure polypropylene.
Chemistry of wood
Mohammad ali Azad far; Rabie Behroz; Ahmad Jahan - Latibari
Abstract
The influence of oxygen delignification as an environmental friendly process, was investigated on Soda/AQ pulp from Old Corrugated Container (OCC) fibers. Oxygen delignification at four levels of alkali (2, 3, 4 and 6% based on OD weight of pulp) has been applied and the optimum alkalinity to reach optimum ...
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The influence of oxygen delignification as an environmental friendly process, was investigated on Soda/AQ pulp from Old Corrugated Container (OCC) fibers. Oxygen delignification at four levels of alkali (2, 3, 4 and 6% based on OD weight of pulp) has been applied and the optimum alkalinity to reach optimum Kappa no, yield and brightness, opacity and strength based on 60 g/m2 hand sheets were determined. The results indicated that application of oxygen delignification marginally reduced the opacity of the pulp. Tear strength increased where as tensile and burst strength decreased. Based on the comparison of the data from oxygen delignified pulp, it is concluded that oxygen can be utilized to improve the properties of soda-AQ pulp from OCC prepared for bleaching step. Carbohydrates are preserved while removing lignin. Normalized equations revealed that oxygen delignification at 3% alkali produced the best results.
