Iranian Journal of Wood and Paper Science Research
Year:2015 | Volume:30 | Issue:1|Papers Count:19

In the present study, preparation of cotton stalk (Sahel variety) as one of the common agricultural residues was studied through three stages as Soda-AQ chemical pulping, delignification and alkaline treatment, aiming for the production of cellulose nanocrystal. In order to identify the optimum condition for the preparation of cellulose nanocrystal, acidic hydrolysis of the produced alpha-cellulose was done using 64% sulfuric acid, 25, 35 and 45 minute as time and at 35, 45 and 55oC as temperature. Atomic Force Microscopy (AFM), XRay Diffraction, and Dynamic Light Scattering (DLS) were used to identify the quantitative and qualitative properties of cellulose nanocrystals. AFM micrographs showed that more severe condition of the treatments decreased the thickness of the cellulose nanocrystals. XRD results also demonstrated that the preparation stages of alpha-cellulose as well as acidic hydrolysis treatments much effectively increased the degree of crystallinity. DLS results indicated that 98.7 percent of the produced nanocrystals under the condition of 55oC and 45 minute were in the range of 18-95 mm., whose highest abundance was in the range of 18-39 mm. Thus, the mentioned condition were determined as the best and optimum condition for the production of cellulose nanocrystal from cotton stalk cellulose.

After water purification and softening, a lot of calcium carbonate with other impurities produce and these byproducts gather and bury as mineral sludge. In this research, The quality of calcium carbonate from water softening process in mazandran wood and paper industry (MWPI) mill and effects of loading of this byproduct on fine paper production was investigated and the results were compared with other industrial fillers like grounded calcium carbonate (GCC) and precipitated calcium carbonate (PCC) and also china clay (kaolin). From the paper structural viewpoint, the fine paper that filled with water softening calcium carbonate (derived after water softening process) have more bulk (bulkier) and more porous and rougher surface compare to fine papers that filled with the common industrial fillers. From the paper strength properties viewpoint, the fine paper that filled with water softening calcium carbonate have less decrease in tensile and burst strength but have not suitable tear strength properties. From the paper optical properties viewpoint, the fine paper that filled with water softening calcium carbonate, because of particles size and impurities of this filler have the least light scattering coefficient and consequently have less brightness and opacity. Adding of 10 and 20 percent precipitated calcium carbonate to by water softening calcium carbonate cause paper porosity and strength decreasing but the optical properties of hand sheets was increased.

The influence of different dosages of surfactant and soap in the deinking of wastepaper is investigated. The results showed that the dosage of 0.25% soap generated highest brightness and lowest opacity. However, the dosage of 0.75% soap produced highest tensile and burst strength and 0.5% soap produced the lowest spec (dirt) index. In the case of surfactant application, the dosage of 0.75% surfactant produced highest brightness and 0.5% surfactant generated lowest opacity. Application of 0.5% surfactant showed highest tensile and burst strength and lowest dirt index. The combined effect of both chemicals showed that the combined dosage of 0.75% surfactant and 0.25% soap produces highest brightness but the dosage of 0.25% surfactant without soap produced lowest opacity. Highest tensile and burst strength was related to pulp deinked using 0.5% surfactant and 0.75% soap. The results indicated that the combination of 0.75% surfactant and 0.25% soap generated highest brightness which the important property of the writing and printing paper. The highest tensile and burst strength was measured in deinked pulp produced using 0.5% surfactant and 0.75% soap.

In this study, the effect of using waste of Alnus subcordata and Poplar wood in manufacturing particle board was investigated. The particle boards were produced by adding (0-25-50-75-100) % alder branches with poplar wood and two press temperatures 170oC and 180oC. In total, 30 particleboards (10 treatments with 3 replications) were made and data was analyzed with complete randomized design. Results showed that particleboards which were made of 75% alder branches and 25% poplar wood with press temperature of 180oC had the most flexural strength. In addition, this study manifests that the increase of alder branches up to 25% led to the enhancement of modulus of elasticity of particle boards while adding more than 25% caused in the decrease of the modulus of elasticity. The increase of alder branches would augment the internal bounding and thickness swelling of particleboards. Therefore, the particleboards of 100% alder branches had the best internal bonding. However, this research concluded that the press temperature would not any significant effected on mechanical and physical characteristics.

In this research, rice straw was used as raw material. Potassium hydroxide was combined with monoethanolamine (MEA) as liquor. In another processes NaOH/Na2So3, KOH/K2So3 and KOH 14% was used as references pulp. The results showed that using pure MEA (15%) produced the highest yield and the highest kappa number. By using potassium hydroxide as a additive agent in MEA pulping, the amount of reject, yield and kappa number was decreased and the lowest yield and the lowest kappa number relevant to MEA (15%) combined with KOH (40%). In addition, in KOH pulping observed that, with increasing concentration of MEA, as additive agent, the amount of total yield increased but the kappa number and reject content was decreased. Results showed that the highest tensile index and tear index were relevant to MEA (15%) combined with KOH (20%) and the highest burs index relevant to NaOH/Na2SO3 treatment. According to the optical properties, it was found that the highest brightness was achieved in K2SO3/KOH. The highest opacity relevant to the KOH 14%. The result shows that MEA process in combined with Potassium hydroxide can be done success fully on rice straw and properties of pulp production, specially in aspect of mechanical strength, in term of combination is superior than soda and Potassium hydroxide process.

In this study, chemical properties of Date Palm residues including cellulose and hemi cellulose content, Lignin content, Extractive and Ash content were determined, and also its physical properties including fiber dimension were measured according to D-2395 ASTM method. The boards made for this study contained 25% lignocellolosic material, Date Palm pruning residues (both fibers and chips) and 75% Gypsum powder. Variable factors were lignocellolosic materials (fibers and chips at different proprotion (0: 100, 5: 95, 10: 90, 15: 85, and 20: 80). Totally, 15 boards were manufactured, and samples of all boards made were tested after curing for 14 days by the methods of Japanese Industrial Standard - R9111 to obtain mean values of Bending strength (MOR), Bending stiffness (MOE), Internal bond strength (I.B), thickness swelling (TS) and water absorption (WA). Gypsum particleboard (GPB) has high thickness swelling (TS), high water absorption (WA), and low mechanical properties compared with GPB reinforced fibers. The properties of GPB were improved by adding fibers. The experimental results showed that GPB with the added fibers had good physical and mechanical properties compared with those of gypsum particleboard with no added fibers. On the other hand, based on the achieved results both mechanical and physical properties of boards increarse with increasing the fiber proprotion. It can be concluded that Date palm fibers are a good material as reinforcement for the manufacture of Gypsum bounded board.

This study and it aim was accomplished on extraction, identification and removal of metallic ions and resins in bleached Bagass pulp by ECF stages. For this purpose, the samples were randomly selected from soda unbleached pulp of Pars mill. The first, pulp flour provided and measured ash and extractive percent by the TAPPI standards. Then the mineral compounds dissolved in 65% nitric acid and the mineral compounds of pulps identificated by Atomic adsorption method. The results of this study showed that the most of Pb, Cu, Zn ions were in H2O2 bleached pulp, the most of Ni ion in OD (Ep) P stage and the most of Fe ion in unbleached soda pulp. The results showed that OD (Ep) D stage decrease Fe ion and EH stage decrease Ni, Cu and Zn ions in pulps. The results of GC-MS diagram showed that 35 compounds were identified in unbleached soda pulp after cooking, that 1, 2-Benzendicarboxylic acid, Hexadecanoic acid, Hexadecan, Octadecan, p-Xylene, 4-Hydroxy-4-Methyl-2-Pantanone, Ethylbenzen and Dodecan were important chemical components in samples. In generally, 17, 12 and 14 compounds were identified in EH, OD (Ep) P and OD (Ep) D bleaching stages, respectively, so that, 1, 2-Benzendicarboxylic acid and p-Xylene were 2 common and important chemical components in all samples and Octadecan and 9-Dodecanoic acid remove as two components from pulps after bleaching, too. The results showed that EH, OD (Ep) P and OD (Ep) D bleaching stages were very important in bleaching, removal of chemical components and brightness stability of soda pulps.

The main objective of this research was to study the potential of bagasse fibers as reinforcement for thermoplastics as an alternative to wood fibers. The effects of three grades (Eastman G-3003, G-3015 and G-3216) of coupling agents on the mechanical properties were also studied. In the sample preparation, one level of fiber loading (40 wt.%) and three levels of coupling agent content (0, 2 and 4 wt.%) were used. For overall trend, with addition of three grades of the coupling agents, tensile, flexural and impact properties of the composites significantly improved, as compared with untreated samples. In addition, morphological study (SEM) revealed that the positive effect of coupling agent on interfacial bonding. The composites treated with G-3216 gave better results in comparison with G-3003 and G-3015 in which, There are some voids where the fibers have been pulled-out. The presence of these voids means that the interfacial bonding between the fiber and the matrix polymer is weak. This could be caused by the high melt viscosity of G-3216 Coupling agent.

In this study the effects of aluminum dioxide (Al2O3) and copper oxide (CuO) metallic nanoparticles, on the physical and mechanical properties of medium density fiberboard (density of 0.7 g/cm3) made with mixture of industrial wooden fibers and sunflower plant stalk fibers were studied. Two levels of raw material including industrial fibers and sunflower stalks fibers, with five levels of mixing ratios (100: 0, 0: 100, 50: 50, 25: 75, 75: 25), metallic nanoparticles with concentration of 400 ppm each at two levels of 2 and 4 percent (based on dry fiber weight) were used. Physical and mechanical properties including thickness swelling, water absorption after 2 & 24 hours soaking in water, modulus of rupture, modulus of elasticity of bending and internal bonding of the samples were measured and analyzed statistically. The results showed that higher percentage of nanoparticles and industrial fibers and lower percentage of sunflower stalk fibers increased the modulus of rupture and modulus of elasticity. Applying nano-metal treatment reduced water absorption and thickness swelling after 2 and 24 h soaking in water. In overall, using 4% nano aluminum dioxide and 4% nano copper oxide at all levels of mixing ratios were resulted in producing boards with better properties, comparing to the EN 622-5 standard specifications, which are suitable for interior uses.

Cordia (Sepestan in Persian) species (Cordia myxa L.) is in the borage family (Boraginaceae) and it is growing with geographical distribution in the moderate and tropical regions of Iran such as near the Persian Gulf, especially in Bandar Abbas and some places in Kerman and Sistan and Baluchestan region but its anatomical characteristics have not been studied yet. In this study, some of the anatomical, chemical and physical properties of Sepestan wood in Iranshahr region in Sistan and Baluchestan Province were measured. Anatomical studies showed that this species has average diameter vessels, simple vascular perforation plate and intervessel pits alternate. Its ray xylems type is heterogeneous and contains abundant crystals. The wood tissue is parenchyma with abundant prismatic crystals and in the cross-section parenchyma was observed in gregarious and continuous formation. Average length, overall diameter, lumen diameter and wall thickness of the fibers were measured 1329, 33.5, 21.7 and 5.9 microns respectively. Also investigation of chemical characteristics showed that Sepestan wood has average cellulose 34.75, lignin 20.6, extractives soluble in acetone 7.88 and also 8.9 percent ash. The results also showed that the specific gravity of the wood is 0.4 and maximum volumetric swelling and shrinkage were 10.98 and 12.34 percent respectively.

This study aimed to investigate the effect of chemical treatment of wood material on functional properties of wood flour / polypropylene hybrid composite. For this reason, first of all, mixed hard wood were separately treated by acetic acid, sodium hydroxide and hot water and were compared with control (untreated) samples. After chemical treatment, wood flour and polypropylene with weight ratio of 50 to 50 and 3 phc of compatibilizer combines in the internal mixer and at last the WPC composite were made using injection molding. Then mechanical tests included bending resistance, tension and impact and physical examination, including water absorption and thickness swelling after 2 and 24 hours was performed on specimens according to (ASTM) standard. Also to study the morphology of the composites, scanning electron microscopy (SEM) was used. The results of this study showed that by chemical treatment the mechanical strength increased and physical properties such as water absorption and thickness swelling decreased. So that the highest flexural strength, tensile and flexural modulus is related to alkali treatment and the highest tensile modulus and impact resistance is related to the acid treatment. Also the lowest water absorption and thickness swelling was related to the alkali treatment. In order to ensure chemical treatments, Fourier transform infrared (FTIR) and weight percent gain (WPG) was used on wood flour.

In the present research improvement of dimensional stability and mechanical properties of gypsum particleboard by using white cement was investigated. In manufacturing gypsum particleboard, Micronize gypsum was used in three levels of 2.5: 1, 2.75: 1 and 3: 1 to dried mass of wooden materials. White cement was added in 2 levels of 5 and 10% based on oven dried mass of gypsum to reinforce gypsum particleboard properties. Water absorption, thickness swelling after 2 and 24 hours immersion in water, bending strength, modulus of elasticity and internal bond strength were measured. Vicat needle method was used to investigate the effect of adding cement on setting time of gypsum. The results showed that adding 5% cement based on oven dried mass of gypsum, increased setting time and also mechanical properties. Adding cement over than 5% (10%), significantly improved dimensional stability but reduced setting time of gypsum and mechanical properties of the boards. On the other hand, results indicated that using Micronize gypsum to 2.75 times to dried mass of wooden materials, increased bending strength and modulus of elasticity. Increasing gypsum in to 3 times, reduced bending strength and modulus of elasticity, but improved internal bond strength and dimensional stability.

This study seeks to investigate the possibility of producing polypropylene composite- cotton stalk flour with various percentages of cotton stalk flour. Determining the best treatment in terms of physical and mechanical properties and exploring the effect of using cotton stalks in the production of the composites were among the major objectives of this study. Six treatments consisting of Polypropylene, 40, 55 and 70 percent level of cotton stalks and two fillers (cotton stalks with and without barks) were developed. Maleic anhydride modified polypropylene (3% wt) was applied to each treatment. The mixing and granulation of the plastic and cotton silk flour was carried out using twin screw extruder model 4815. After preparing and shearing of samples, the mechanical properties of composites including tensile strength, rupture modulus and elasticity modulus were calculated in accordance with D-6109 and ASTM D-7031 standards. In addition, water absorption and thickness swelling tests were performed according to D-570-98 standard. The results showed that an increase in the flour of cotton stalk reduced the tensile strength and rupture modulus on the one hand, and increased the bending elasticity modulus on the other hand. In terms of the performance of the filler, there was a significant difference between values of rupture modulus and elasticity modulus at 95% level whereas this difference was not significant for tensile strength. Moreover, this difference was significant for values of water absorption and thickness swelling. The maximum tensile strength belonged to T4 with 40 percent of cotton stalk bark fibers.

This research was performed to evaluate the potential of acid pre-hydrolysis soda-AQ process for the production of dissolving pulp including high a-cellulose content from Populus deltoides. To achieve the aim, a pre-hydrolysis liquor containing 0.06% acid sulfuric, soda-AQ pulping, and OD0ED1 bleaching sequence were used. The results show that using at least 0.40 kappa factor at D0 stage was necessary to gain access a high quality dissolving pulp including characteristics like having brightness level and a-cellulose content higher than 86% and 98%, respectively. A kappa reduction of 40.3% was achieved by performing a single stage oxygen delignification after soda-AQ pulping to drop kappa number of pulp from 14.1 to 8.4 prior to entrancing the pulp into the final bleaching stage. The results illustrated that producing acid pre-hydrolyzed soda-AQ dissolving pulp including high a-cellulose content and brightness, and even viscosity is completely feasible through controlling and optimizing the acid pre-hydrolysis, pulping, oxygen delignification stages, and D0ED1 bleaching sequence.

In this research the effect of oil-heat treatment of Fir species (Abies spp) on contact angle and adhesion strength of organic solvent based and water based coating (acid catalyzed and water based acrylic coating) were investigated. Soy oil was used for the heat treatment modification. Modification process of samples were done at two time, 12 and 15 hours with temperature of 180oC. Control and modified samples were covered with acid catalyzed and water based acrylic coating. Contact angle of water was measured before and after treatment. Adhesion strength of coating was determined according to ASTM 4541 standard. Obtained results of contact angle and adhesion strength were compared with the control samples. The results showed that modification process of oil-heat treatment increased contact angle. This increase continued by increasing treatment time. Increasing contact angle reduced wettability of samples’ surface. On the other hand oil-heat treatment of wood, decreased adhesion strength of coating. The lowest value of adhesion strength was observed in the modification process of 15 hours. Results of comparing coating revealed that acid catalyzed coating had higher adhesion strength than water based acrylic coating but generally no significant differences was observed between these coating.