جعفر ابراهیم پور کاسمانی

The aim of this study was to compare the effect of nanocellulose and nanosilica on the properties of packaging cardboard made from waste white pulp. In this study, waste pulp was transferred to the laboratory. Handsheet cardboard was made of 60 g.m-2 with 4 and 8% nano-silica condition, and nanocellulose and cationic starch at 1.5% level. Finally, the physical, mechanical and morphological properties of the prepared cardboard were tested according to the TAPPI standards and compared with each other. The results showed that 4% cellulose nanofibers and 1.5% cationic starch had 2.5, 14.1, 46.9, 35.9, 9.5, 8.9, 20.5 and 5.1%, respectively, water absorption, surface smoothness, tensile strength index, burst resistance index, tensile strength index, brightness, whiteness and opacity more than 4% cellulosic nanofibers and have 30.9%, 19.3% of air resistance, and fewer yellowness than 4% cellulose nanofibers. 8% cellulose nanofibers and 1.5% cationic starch have 16.1%, 43.7%, 7.6%, 21.3%, 10.7%, 6.1%, 1.1%, 6.6% of water absorption, air resistance, tensile strength index, burst strength index, tear strength index, brightness, whiteness and opacity are higher than 8% cellulose nanofibers and have 36.2 and 23.1% surface fines, respectively, and fewer yellowness than 4% of cellulosic nanofibers. 4% nano-silica and 1.5% cationic starch have 8.1%, 18.3%, 34.1% and 6.9% surface smoothness, whiteness and opacity, more than 4% nano-silica, respectively, with 10.1% 13.1, 10.8, 1.5, 9.9 and 75.2% water absorption, tensile strength index, burst strength index, tear strength index, brightness and fewer yellowness than 4% nano-silica. 8% nanosilica and 1.5% cationic starch have 1, 14.7, 40.2 and 6.7% water absorption, air resistance, whiteness and opacity are more than 8% nano-silica, respectively, and have 5.2, 36.3, 69.3, 74.5, 5.1, and 14.8 percent surface smoothness, tensile strength index, burst strength index, tear strength index, brightness and fewer yellowness than 8% nano-silica. The results showed that the use of cellulose nanofibers is more preferable, and it can be important because it leads to a decrease in imports.

Waste paper recycling has grown as an industry in Iran and the world and offers many benefits to the environment and humans. Municipal waste is also reused after recycling processes. Cardboard recycling industry has great environmental and economic importance and with the lack of wood resources and high demand for paper products, it plays an important role in the development of paper-related industries. However, recycling can be associated with a reduction in the optical properties of the paper. The use of nanoparticles in the paper industry is also expanding day by day. Nanosilica is one of the most important nanoparticles used as a retention aid in the paper industry. In order to reduce the consumption of long fibers and obtain the desired optical properties, the use of nanosilica alone or in combination with other materials such as cationic starch and cationic polyacrylamide is investigated. The purpose of this research is to compare the effect of separate and combined use of nanosilica additives, cationic polyacrylamide, cationic starch and long fibers on the optical properties of white liner paper pulp. In this study, white paper pulp with a brightness of at least 78% and a gloss of at least 45% was used to prepare handmade papers. Long fiber chemical paper pulp from coniferous kraft imported from Russia with a brightness of 89% was used in the laboratory. Nanosilica powder (NanoSiO2) produced by Degussa, Germany, cationic polyacrylamide with Farinret K325 brand, produced by Degussa, Germany, and cationic starch from LyckebyAmylex, Slovakia, were used. Independent treatments include the addition of 10% refined long fibers paper pulp, 6% nanosilica, 1.5% cationic starch and 0.15% cationicpolyacrylamide and combined treatments include 6% nanosilica and 1.5% cationic starch and 6% nanosilica and 0.15% cationic polyacrylamide. Then 127 g.m-2 handmade papers were prepared and their optical and microscopic properties were evaluated. The results showed that by adding 10% of long fibers, the brightness decreased and by using 6% of nanosilica, the maximum brightness was obtained. Meanwhile, the whiteness of papers with 6% nanosilica was minimum and maximum with 0.15% cationic polyacrylamide. Opacity showed its highest value with the combination of 6% nanosilica and 0.15% cationic polyacrylamide. Also, by increasing the amount of polyacrylamide and cationic starch, individually or in combination with nanosilica, the opacity increased. The light absorption coefficient was the lowest in papers with 6% nanosilica and the light scattering coefficient was the highest in papers containing 6% nanosilica and 0.15% cationic polyacrylamide. A colorimeter was used to measure the color components and the results showed that the additives had an effect on the brightness and whiteness of the papers. Also, changes in the color spectrum and the amount of color change were also observed. Additives increased the darkness and changes in different colors. The use of nanosilica separately and in combination with starch and cationic polyacrylamide increases the brightness of papers. Also, the use of cationic polyacrylamide separately and in combination with nanosilica leads to an increase in the whiteness and opacity of papers. The brightness factor of the papers, which is representative of the L* component, decreased with the exception of the addition of 10% long fibers and 6% nanosilica. The amount of overall color change with ∆E* was the lowest in samples containing 1.5% cationic starch and the highest in samples containing 0.15% cationic polyacrylamide. The use of some treatments can lead to a decrease in the optical properties and a decrease in the printability quality of the white liner. To solve this problem, mechanical paper pulp that has been decolorized or coated on the surface of the paper can be used. The presence of nano-silica particles in the structure of the paper improves the bond surface and reduces the prosity, which results in the reduction of surface roughness and less light refraction, and increases the light reflection and brightness of the paper.

Eggs are an inexpensive food with various nutrients and high biological value. The decline in egg quality starts immediately after laying and progresses rapidly depending on the storage conditions. To aim of preventing the penetration of microorganisms and gas and mass exchanges, various approaches were studied based on inactivating microorganisms and coating the pores on the eggshell, in order to maintain the quality and extension of the egg shelf life. As an alternative to the traditional packaging of eggs and other food products, using biodegradable wrappers based on agricultural and food industries waste was associated with successful results. Polysaccharide packaging materials are low-cost and available, but they are not considered suitable wrappers against the penetration of water vapor, so this problem can be solved by applying physical and chemical modification methods and creating composite and active wrappers. Using food wrappers in the form of biodegradable packaging, in addition to preventing food wastage and longer protecting food, is an effective approach to overcoming the problems of waste disposal. At the same time, proper design and appearance, economic justification, using devices and practical methods in preparation, and appropriate, compatible, efficient and competitive formulation should also be considered.

This study was conducted with the aim of investigating the effect of layer coating of nano polyurethane and nanoclay on improving the properties of cold-storage white top kraft paper used in the packaging industry. For this purpose, white top kraft paper with a base weight of 131 g.m-2 was prepared and tested. To cover the surface of the paper, nano-polyurethane was first applied by spraying with a nozzle in an amount of about 15 g.m-2 on the surface of the white top paper. In the second stage, to improve the performance of the coating material of the first stage, the surfaces of cold-storage white top kraft paper were covered with nanoclay by a laboratory coating machine. In this step, the coating material was coated with the amount of 27 g.m-2 on the upper surface of white kraft paper. After being coated and restrained, the samples were dried at room temperature for one day to stabilize the coating material on its surface. Then, the samples were placed inside the freezer for 2 and 4 months and their properties were measured. Before the tests, the control and coated samples were placed in standard environmental conditions (at a temperature of 20 οC and relative humidity 65%). The results showed that the coating (control) increased the thickness, smoothness of the surface, and the resistance against the ring crush of the paper in the direction of the machine and reduced the water absorption, brightness and other mechanical properties such as the tensile strength index machine direction (MD) and cross direction (CD), burst strength index, tear strength index (MD and CD),  and ring crush test in the cross direction in frozen coating samples with increasing thickness and surface smoothness; a decrease in other mechanical properties was observed. The samples coated twice showed very few pores. The thickness and surface smoothness of white coated kraft paper showed an increase of 30.8% and 37.7%, respectively, compared to the control sample. Water absorption, burst strength index, tear strength index (MD and CD), tensile strength index (MD and CD), ring crush test (MD and CD), and the brightness of the double-coated white kraft paper compared to the control sample, respectively showed a decrease of 151, 87.4, 15, 13, 104.2, 103.2, 67.1, 82.3 and 11.8%. According to the obtained results, it is recommended that papers such as liquid packaging cardboard, juice and milk packets, which have many applications in food packaging, should be tested with these coatings with different times.

This research was conducted with the aim of investigating the effect of two-layer coating of nano-polyurethane and nano-clay on the mechanical and physical properties of packaging cardboard with brown layer. For this purpose, brown layer cardboard with grammage of 127 was prepared and tested. To coat the surface of the cardboard, it was first coated with nano-polyurethane and sprayed by a coating nozzle. Then the surface of the brown layer cardboard was covered with nano-clay to improve the performance of the coating material of the first treatment. Nano-clay coating was performed by a laboratory coating machine called barcoter. The coated cardboards were restrained and dried in the room for one day to stabilize the coating material on their surface. Then the samples were placed inside the freezer for 2 and 4 months and their properties were measured. The results showed that coating reduced water absorption. In the coated and frozen samples, an increase in thickness, smoothness of the surface and a decrease in water absorption and resistance properties compared to non-frozen control samples have been observed. Double coated samples showed very few pores. The thickness, smoothness of the surface and resistance to tearing in the machine cross direction of the double coated brown cardboard showed an increase of 13.7%, 75% and 3.8%, respectively, compared to the control sample. water absorption, resistance to bursting, resistance to tearing in the machine direction, resistance to tensile in the machine direction, resistance to tensile in the cross machine direction, resistance to ring crush test in the machine direction and resistance to ring crush test in the cross machine direction of the double-coated brown layer cardboard compared to the control sample, showed 107.20, 1.5, 34.3, 25.4, 24.3, and 4.7 percent decrease respectively.

This research was conducted with the aim of investigating the effect of using biodegradable nanostructure coatings on water absorption and other physical and mechanical properties of white paper used in cold environments. For this purpose, 127 g/m2 white paper was prepared and tested. First, the liners were mounted on a plywood. After applying the coating and preparing several samples, papers with the same coating weight were selected for testing. Due to the impossibility of exact coverage amount, liners with a coverage of about 15 g/m2 were used for the next tests. After the application, the coated papers were dried at room temperature. Then the samples were placed in the refrigerator for 2 and 4 months. Before the test, the control and coated samples were placed in standard environmental conditions (temperature 20 οC and relative humidity 65%). The results showed that the water absorption of the samples decreased after coating. The reason for this is that the coating solution used has penetrated the pores of the paper and caused the diameter of the pores to decrease, as a result, the speed of water passing through the pores of the paper has decreased. In coated and frozen samples, an increase in thickness and a decrease in surface smoothness and resistance properties have been observed compared to unfrozen control samples.

In this study, optical properties of paper obtained from treatments 1, 2 and 4 weeks with the fungus Phanerochaete chrysosporium BKM - 1767 was evaluated and compared with control samples. After preparing fungal specimens, hornbeam chips three levels 1, 2 and 4 weeks under laboratory conditions were treated. To Chemical Mechanical Pulping from chips treated, 165oC baking temperature, cooking time 80 and 90 minutes and the percentage of sodium sulfite chemicals: 14, 18 and 22 percent compared to the cooking liquid to chips 7 to 1 was considered. In the case of brightness, the duration of treatment is also an important factor for increasing the effect of fungal treatment. The decrease in brightness in the 4-week treatment is significant. This point indicates that in the case of hornbeem, the effect of the fungal treatment on the brightness of the paper occurs only in the 4-week treatment. More increase of yellowness in 2 and 4 week treatments shows that the effectiveness of hornbeem in relation to the yellowness factor occurs with increasing the duration of fungal treatment. The opacity of the papers obtained from the treated wood chips has almost increased, but there is no significant difference between the opacity of the papers prepared in the control treatment and the opacity of the papers prepared in the fungal treatments.

This research was conducted with the aim of studying the effect of spraying with nano-polyurethane and freezing the treated samples on the physical and mechanical properties of brown liner paper. For this purpose, 128 g.m-2 paper was prepared and its characteristics were evaluated. To coat the surface of the paper, nano-polyurethane is first sprayed using a sprayer in an amount of about 15 grams per square meter for each surface. Then, the coated paper is placed in the environment and the oven (temperature of about 70 οC) to dry, so that the coating material stabilizes on its surface. Then the samples were placed inside the freezer for two and four months, before the tests of the control and coated samples, they were placed in standard environmental conditions (temperature of 20 οC and relative humidity of 65 %). The results showed that spraying increased thickness, decreased water absorption, and increased burst streangth, increased tear streangth. Also, there was no specific change in tensile strength and ring crush test. In sprayed and frozen samples, with the increase in thickness, water absorption and tensile strength decrease, burst streangth and tear streangth compared to non-frozen control samples, an increase was observed. Ring crush test against the was also not significant. The sprayed samples showed very few pores. The thickness and tear streangth in the machine direction of the one-time sprayed brown liner paper increased by 8.96% and 2.3%, respectively, compared to the control sample. water absorption, tensile strength and tear streangth, burst streangth and ring crush test against the ring in the machine direction of one-time sprayed brown liner paper compared to the control sample showed decreased as 19.53, 3.83, 2.4 and 3.14, respectively.

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.

This study was performed in order to compare the independent and combined effects of four types of additives including cellulose nanofibers, cationic polyacrylamide, cationic starch, and imported long fiber pulp in the handsheet prepared from office waste paper. Independent treatments included the addition of 15% long fiber pulp, 3% cellulose nanofibers, 0.75% cationic starch and 0.07% cationic polyacrylamide. Combination treatments included firstly addition of 0.75% starch and then 3% cellulose nanofibers, and also 0.07% cationic polyacrylamide and 3% cellulose nanofibers. Handsheets with grammage of 60 g/m2 were made from seven furnishes and finally the physical, mechanical and microscopic structures of the handsheet were investigated. The results showed that addition of long fiber pulp, cationic starch, cationic polyacrylamide and cellulose nanofibers slightly reduced the density of handsheets compared with the control. The highest surface smoothness was achieved using combined treatments of cellulose nanofibers, which could improve the printability of the paper, but decreasing the air permeability and reducing the water drainage of the sheet by adding cellulose nanofibers could cause problems on paper and printing machines. Tensile, burst and tear indices of handsheets had the highest increase by the addition of 15% long fiber pulp, and then using 0.75% cationic starch improved the strength compared with other treatments. Electron microscopy images showed a relative reduction of porosity in the handsheets made from cellulose nanofibers, which could have negative effects on water drainage of recycled pulp.

This study aimed to investigate the use of cellulose nanofibers and starch-nano-cellulose and polyacrylamide-nano-cellulose hybrid systems for the replacement of imported long chemical fibers in the production of these papers. In this study, imported long fiber chemical pulp was added to cotton pulp at 4 levels. Cellulose nanofibers were added to cotton pulp at a 5% level with 1% starch and 0.1% with polyacrylamide. Three levels of cationic starch and three levels of cationic polyacrylamide were also used. From each of the treatments, 60 gm-2 handsheet were made finally the physical, mechanical and optical properties of the paper made from different pulps were compared. The results showed that with increasing nanocellulose individually, compared to imported long fibers, surface smoothness, tensile strength, bursting, tearing of paper increased and air resistance, folding resistance and opacity decreased. Increasing nanocellulose in combination with cationic polyacrylamide increased the paper air resistance and surface area, tensile, burst, tear, and folding strength of the paper compared to imported long fibers, air resistance and opacity. With the increase of nanocellulose in combination with cationic starch, as compared to imported long fibers, surface smoothness, tensile strength, bursting, folding increased but opacity decreased. FE-SEM results also showed that with increasing percentage of cellulose nanofibers, the pores decreased significantly. As a result of the addition of 5% cellulose nanofibers the surface of the paper became smoother and the pores were filled relatively, confirming the results of surface smoothness and air resistance.

This study was done to replace the imported long-fiber chemical pulp (LFCP) by adding nano lignocellulose fiber (NLCF) and dual composition of nano-cationic starch (CS) and nano- cationic polyacrylamide (CPAM) for preparing durable paper made from waste lint recycling combing machine. For this purpose, 5% unbleached NLCF and 1% CS or 0.1% CPAM were mixed to waste lint pulp (WLP) as the control. The LFCP was added to the WLP in three amounts of 10%, 20%, and 30%. Also, CS and CPAM at three levels were used separately in WLP. Handsheets were made from 13 types of pulp compositions in grammage of 90 g/m2 and their physical, mechanical and optical properties were measured according to the relevant standards. Based on the results, addition of 1% CS to the control pulp (except for the paper yellowness) could be a good substitution for the LFCP. Also, the addition of NLCF resulted in a significantly decrease of handsheet’s brightness and an increase of handsheet’s yellowness. Furthermore, double fold endurance and softness of handsheets decreased compared with the LFCP, which might be due to the accumulation of NLCF on the surface of the paper according to SEM images. The addition of 0.05% CPAM except for double fold endurance could improve the paper properties compared with using LFCP in WLP. Nano-particle dispersion somewhat improved using dual composition systems and the addition of nano-CS revealed that the paper strength improved compared with using NLCF alone and nano-CPAM.

This research was carried out with aim of the effect of nano-clay (NC) content on mechanical, thermogravimetry (TG) and morphological properties of wood plastic composite (WPC) made of medium density fiberboard (MDF) and particleboard (PB) wastes and recycled polypropylene and polyethylene (HDPE). For this purpose, wastes of MDF and PB at 50 wt.% , recycled PP and HDPE at 50 wt.%, maleic anhydride grafted with polymers at a constant level of 3 wt.% and nanoclay at three different levels 3, 6, and 9 wt.% were blended by two-wire extruder. Afterward, standard test pieces were made using an injection molding machine and their mechanical properties and TGA were investigated. Scanning electron microscope (SEM) was applied to investigate the quality of nanoclay particles dispersion in the matrice as well as how the lignocellulosic and polymers are bonded at the surface of bonding. The results showed that tensile and flexural strength and their modulus of HDPE and PB composite significantly were increased by adding NC up to 3 wt.%, but the strengths were dropped in WPC's by increasing of NC content at 6 and 9 wt.%. The notched impact strength of WPC has been totally decreased by NC addition that indicates more fracture surface on WPC's. SEM micrographs revealed that porosity and cavities in WPC's especially were decreased at 9 wt.% NC, whereas it is clear an inappropriate dispersion and aggregation of NC in WPC. The thermal stability of WPC's was slightly improved at 3 wt.% NC and the residual after combustion increased compared to the control.

Annually huge amount of un-used rice straw after rice harvesting were burned due to no specific utilization. Whereas, based on the biorefinery concept there is possibility to use these agricultural residues for production of high value added products. So, this study was aimed to extract the silica from the rice straw (Oryza Sativa var Indica) as one of the important agro-industrial residues in the country and its capabilities for production of silica nanostructures based on the mentioned concept. After washing, drying and grinding of rice straw samples, some of them were separately leached with a hydrochloric acid and some ones with a sulphuric acid at concentration of 0.5 M for 30 min with constant stirring. Afterwards, the silica content of acid-leached and un-leached rice straw samples was measured in a muffle furnace with varying temperatures at 500,600, 700, 800 and 900°C for 2 h. The results were obtained from Energy Dispersive X-ray (EDX) and X-ray Fluorescence (XRF) demonstrated the maximum presence of silica into the rice straw ash. Two of aforementioned spectroscopy methods explored the higher content and purity of acid-leached rice straw samples in comparison to un-leached rice straw ones. The Field Emission Scanning Electron Microscopy (FESEM) images demonstrated that the prepared silica nanostructures had a spherical shape and their average particle sizes were 30 nanometer for un-leached rice straw samples and less than 12 nanometer for acid-leached ones.

In textile industry the bellow comb fibers are located in a range in terms of their length and diameter that it can be used as proper raw material especially in paper dough industries; therefore, present study tries to consider improvement of durable paper's properties made of cellulosic nanofibers. In this consideration, the below comb fiber of pulp and paper imported chemical pulp are prepared from a company that is producing durable papers and they were transferred to laboratory. Cellulosic nanofiber has been prepared from Nano Novin Polymer Co., and it has been consumed at 4 levels of 0, 0.3, 0.6 and 0.6%. After mixing pulp with cellulosic nanofiber at determined percentages, the handmade 90 g.m-1 papers were made and eventually physical and mechanical properties of these papers were evaluated. The results showed that enhancement of cellulosic nanofibers till 0.9% has led to enhancement of tensile strength, bursting resistance, tearing strength and folding strength comparing to control sample up to 22.7, 38.9, 7.7 and 384% respectively. Increasing the amount of cellulosic nanofibers up to 0.9% the surface smoothness has increased up to 7.9% comparing to control; moreover, water absorption and pores were reduced as 69 and 7.9% respectively. The SEM results showed that enhancement of cellulosic nanofiber percentage has led to reduction of pores.

The main goal of this study was to explore the level of adding precipitated calcium carbonate (PCC) filler to the kraft fibers which treated by Layer-by-Layer (LbL) method. The kraft fibers treated by three layers of cationic starch-nanosilica-cationic. Then, the standard handsheets (60±3 g/m2) were made from untreated and treated fibers. The results showed that by using 3-layers treating of kraft fibers, tensile index was improved from 23.96 N.m/g to 38.50 N.m/g. In addition, the burst and tear index was increased from 1.46 kPa.m2/g to 3.58 kPa.m2/g and 9.14 mN.m2/g to 15.99 mN.m2/g respectively. Also, the SEM images illustrated the fibers surface gelation due to the cationic starch absorption and an improvement of bonded area in fibers network. Furthermore, the three levels of PCC filler (5, 10, and 15%) were added to the 3-layer treated kraft pulp and strengths loss was evaluated and compared to the untreated pulp. Tensile, burst, and tear index were measured and they were 24.01 N.m/g, 1.20 kPa.m2/g and 9.49 mN.m2/g respectively by adding 10% of filler. According to the ANOVA test, the results revealed that it is possible to add 10% of PCC filler to the kraft pulp which treated with LbL method. Furthermore, SEM images indicated the retention as well as relatively uniform distribution of the PCC filler in the fibers network particularly in the area which impregnated with cationic starch.

Addition of mineral fillers to the paper pulp results in improvement of some important paper properties. But the paper mechanical properties would decrease due to the impossibility of attachment between filler particle and cellulosic fibers and inhibition of fiber-fiber bonds. One of substantial approaches to overcome such restriction is to modify cellulosic fiber surface to improve their bonding-ability with other paper network fragments. Thus filler can be added to the reinforced fibers network. Recent researches show that nanotechnology layer-by-layer method is a good way for modifying the cellulose fibers characteristics and improving its quality. In this technique, cellulosic fibers and counter-ionic particles are placed in an interaction media. During the interaction, ionic particles are absorbed by fibers surface mainly via electrostatic absorption. Therefore the fibers network strength would improve considerably. In current research, CMP fibers was firstly treated with three layer of cationic starch - anionic nanosilica - cationic starch. Then PCC filler was added to the treated pulp in different levels. The extent of strengths improvement with layering treatment and the strength loss due to the PCC addition was evaluated in order to calculate the level of filler application in reinforced CMP pulp.
The layering treatment of CMP fibers was successively conducted using cationic starch polymer and anionic nanosilica. For three subsequent layers constitution, 500 ml pulp suspension with 0.53 consistency was mixed for 10 minutes with solutions of cationic starch (1.5 %) - anionic nanosilica (0.05 %) - cationic starch (1.5 %) applying laboratory mixer. Then PCC filler was added to the 3-layer treated CMP pulp in three levels of 5, 10, and 15 %. Handsheets with 60±3 g/m2 basis weight was prepared from untreated, treated, and treated pulp containing PCC filler; and their physical properties (thickness, apparent density, bulk) and mechanical characteristics (tensile index, burst index, tear index) have been compared. Also, SEM micrographs were prepared from the above samples to evaluate the variation of fiber surface structure and paper network.
The results indicated that by treatment of CMP fibers with layer-by-layer method, there occurs no meaningful variation in paper physical properties. Whereas this system had considerable effect in paper strengths improvement. Evaluation of strength properties showed that by 3-layer treatment of CMP fibers, Tensile index of paper improved from 28.54 N.m/g (in untreated fibers) to 39.18 N.m/g, burst index from 1.36 kPa.m2/g to 2.68 kPa.m2/g, and tear index from 6.11 mN.m2/g to 11.12 mN.m2/g. Also, in prepared SEM micrographs a different appearance in 3-layer treated fibers surface compared to the untreated fibers; indicated an increase in gelatinization of treated fiber surface due to an increase in cationic starch absorption, results to improve the bonded surface between fibers and increase in paper strengths. By adding 10 % of PCC filler to this pulp, tensile index, burst index and tear index was measured 26.40 N.m/g, 1.79 kPa.m2/g, and 8.07 mN.m2/g respectively. Furthermore, SEM micrographs confirmed PCC filler retaining and its relative uniform distribution in the treated CMP fibers network.
Analysis of the results showed that by reinforcing CMP pulp with layer-by-layer method used in current research, paper strength characteristics increases considerably without significant increase in physical properties. From statistical viewpoint, with increasing of the strength in the treated CMP pulp, 10 % of PCC filler can be added to it.

This study is investigates the effect of mechanical properties of CMP pulp treated with P.
chrysosporium fungi. After preparing the fungi sample, provided chips of hornbeam were
treated under 39°C and 65% relative humidity condition in three distinct time of 4 weeks and untreated sample as control. For preparation the CMP pulp from treated chips, pulping temperature were adjusted at 165°C, pulping time at 80 and 90 minutes, and 14 and 22 percent of chemicals charge (sodium sulphite) were used and the ratio of pulping liquor to chips were 7:1. Results showed that fungal treatment reduces fungal resistance indices as indexes of tensile, burst, tear strength and fold endurance.

This research was conducted to study the effect of mixing different contents of old corrugated container (OCC) pulp on mechanical properties of virgin neutral sulfite semi chemical (NSSC) pulp. The NSSC pulp was procured from Mazandaran Wood and Paper Industries Company. For the OCC pulp,old corrugated containers were collected throughout Sari city after removing printed and gluedparts or unwanted objects. Then, the containers were split by hand into similar small parts in order to prevent cutting of the fibers. Afterwards, the OCC pulp was prepared from them. Handsheet papers of 127 g/m2 base weight were prepared from mixing of the NSSC pulp with the OCC pulp in contents of 60, 70, 80 and 100%. Mechanical properties of the produced papers including tensile strength, burst strength, tearing strength and crushing strength were then compared with each other in corrugated case, while squeezing strength was evaluated in ring case using TAPPI standard. The obtained results indicated that increasing consumption of the OCC up to 30%, improves tensile strength, tear strength and burst strength of the handsheet papers significantly in comparison with the control sample (for 21, 25 and 59%, respectively).However, crushing strength in the corrugated case and squeezing strength in the ring case were degraded about 13 and 9%, respectively. The results of this study revealed that mixing 30% of the OCC with the NSSC could yield papers of higher quality.

This study aimed to investigate the effect of nanoclay on physical, mechanical, optical properties and morphological characteristics of the paper from CMP pulp was performed. The amount of nanoclay in six levels of 0, 2, 4, 6, 8 and 10 percent and for retention of the cationic starch 1 percent of all pulps used. After the addition of additives, the handsheets was 60 g/m2 and the physical, mechanical, optical properties and morphological papers made was examined. The results showed that with the increase of nanoclay to 2% increase of the tensile strength and up to 10% reduced. With increasing nanoclay to 4% roughness increase and with 10% reduced. Decreasing trend in average tear strength, burst strength and brightness with nanoclay increasing to the level of 10% was observed. Uptrend in average air resistance, opacity and yellowness by increasing nanoclay the level of 10% was observed. SEM images showed that with increasing levels of nanoclay, somewhat coarse fibers by nanoclay pores are filled why increased air resistance. XRD results showed that the peak of the crystalline area disappeared and morphology of the intercalation formed.

This study was to investigate the the effect of nano-cellulose on the strength of CMP pulp and paper was produced of it. In this study, in order to supply CMP pulp Mazandaran wood and paper mill was prepared. Nano-cellulose in five levels (0, 2, 4, 6 and 8 %) of handsheets of 60 g were made and eventually physical and mechanical properties produced manufactured paper and a level of control, was tested on handsheets paper. With increasing nanocellulose, tensile strength, burst strength, air resistance, brightness and whiteness than the control samples 10.9, 12.5, 23.6, 0.6, 3.5 and 6.8% incresed. With the increase of nanocellulose tear strength, roughness, opacity, compared to the control 10.4, and 11.1, 0.6 % decresed.

This study was conducted to investigate the low weight coating (LWC) effects on mechanical and optical properties of printing papers produced by Mazandaran Wood and Paper Industries Co. (MWPI). Two mineral pigments including nanoclay and precipitated calcium carbonate (PCC) were applied by blade coating method in different weight percentages of latex. Surface structure of coated paper was characterized by atomic force microscopy (AFM). Also، mechanical and optical properties of coated paper and control were measured. Comparison of the characteristics showed that surface of coated paper with nanoclay had better uniformity and smoothness than PCC due to higher specific area and plate form shape. There were no significant differences among the paper strength except tensile stiffness. Yellowness of the LWC paper with nanoclay decreased by approximately 20% compared to the control، whereas there were no significant differences among of brightness and opacity of LWC paper and control.

In this study, wood containing printing paper was coated by latex with nanoclay and PCC loading for printing improvement at two and four levels, respectively. Scanning electron microscope images confirm partial filling and covering of cavities on the surface of base paper by the coating. Rheological behavior and viscosity of two types of color pigment are quite different and PCC would be better because of lower preparation costs. Results showed that the printing paper coating reduced roughness, porosity and water absorption, so printability and dimensional stability of paper would improve in web offset printing. There is significant difference between gloss and print density of coated paper and control at α= 0.01. Apparently, coated paper with PCC showed better print quality than the control. Printing with IGT tester revealed that no picking occurred on coated paper contrary to the control that could be critical for print quality and linting problem on the press rolls. J. Color Sci. Tech. 7(2014), 265-274©. Institute for Color Science and Technology.

In this study, CMP pulp yield and refining energy consumption of treated pulp affected by the fungus Phanerochaete chrysosporium BKM - 1767 were evaluated and compared with control samples. After preparing fungal specimens, hornbeam chips were treated at three levels 1, 2 and 4 weeks under temperature 39oC with relative humidity 65%. For preparing CMP pulp from treated chips, Production conditions were as follows: cooking temperature 165oC, cooking time (80 and 90 minutes), the percentage of sodium sulfite chemicals: 14%, 18%, 22% in comparison to the cooking liquid to chips which was 7 to 1. The results showed that treated wood, rate of output has decreased. In comparison to the control group. The reduction for treatments for the weeks 1, 2 and 4 was about 1.64, 2.84, and 6.20 percent respectively. Furthermore, increasing the consumption of chemicals has increased the yield, which actually increased the severity of reactions compression yield after cooking. The results of refining showed increasing the fungal treatment period caused easier refining and less consumed energy so that the week 4 treatment caused 40% reduction in refining energy.