Iranian Journal of Wood and Paper Science Research
Year:2017 | Volume:32 | Issue:2|Papers Count:16

To study the tensile properties and impact strength in Wood Plastic Composites (WPC) polypropylene as a matrix and teada pine sawdust as reinforcement / filler is used. Ethylene / propylene / Diane / monomer (EPDM) as modified impact resistance with 10, 20 and 30 percent improved impact resistance and maleic anhydride grafted polypropylene (MAPP) at a rate of 3 percent as a fasteners to improve response and polymers and fillers were added to the composite. To evaluate the fracture surface of a structure scanning electron microscope (SEM) was used. The apply of 10% elastomer and 3% coupling agent cause to improved of tensile properties and the use of higher levels of elastomer (20 and 30%) has shown a decreasing trend in these properties. The results showed that PP matrix by adding sawdust to a significant reduction in impact strength of composite than pure PP is observed. An EPDM additive used in all contents of composites PP / sawdust has improved impact strength. Simultaneous use of EPDM and MAPP used a positive effect in tensile properties and impact strength. The apply of EPDM (30%) and 3% (MAPP) has demonstrated the highest level of impact strength. SEM images show that the use of EPDM and MAPP composites will improve the connection of interface.

In this study, the effect of staple length (penetration length) and staple numbers in connection, on the face and edge withdrawal capacity of poplar wood laminated veneer lumber (LVL) frame was investigated. The staples with 3 and 4 cm penetration length in the face and staples with 3, 4 and 5 cm penetration length in the edge were used respectively. Number of staples were selected at 4 levels (2, 3, 4 and 5 no.) as a variable. Results have shown that withdrawal capacity in face significantly increased with increased penetration length. Withdrawal capacity in edge increases drastically with increase of penetration length from 3 to 4 cm, but further increase in penetration length from 4 to 5 cm had no significant effect. Withdrawal strength capacity in face was increased with increase of staples numbers. But, higher number of staples had no significant effect on withdrawal strength capacity in edge. Maximum withdrawal capacity was observed in joints fabricated with penetration length of 4 cm and 5 staples in face and minimum values was observed with penetration length of 3 cm and 2 staples in the edge.

Wood industries need abundant resources of wood raw material and these industries could continue to be productive based on the availability of poplar wood. Due to the importance of poplar farming and its role in the economy of Kurdistan, investigation on the evaluation of its value chain is essential. In this research, the suitable value chains were identified for development. According to the study objectives, the effective criteria to prioritize research alternatives were identified through literature review and then with the help of questionnaires it was completed and confirmed, according to the experts views. The experts were used to identify the interrelations between criteria. After completing the paired comparison questionnaire, weight of each criterion was measured and priorities were found by the ANP. Ultimately, the final results of alternatives ranking showed the most weight is related to the MDF chain with weight of 0.259. The next priorities were paper, straw and cellulose with respective weights of 0.135, 0.134 and 0.115. The next priorities were furniture, particle board, plywood and matches, pallets, boxes, lumber and boards, with weights of 0.096, 0.077, 0.075, 0.073 and 0.019 respectively. Results of group decision-making using ANP showed that in the current situation with regard to the suitable market for MDF, proper future demand, appropriate market for processed products from MDF, condition of infrastructure in Kurdistan province and feasibility to use poplar wood in production of MDF, this industry is more important to be developed in Kurdistan province.

In this study, the relationship between dynamic modulus of elasticity derived from longitudinal vibration method and static modulus of elasticity and bending strength in two directions: Parallel to machine direction and cross machine direction have been investigated.For this purpose, 4 plates of particleboard with the dimensions of 124´90´1.6 cm (length´ width´thickness) were selected and free longitudinal vibration test in PMD and MD were performed on each plates. Then, the primary plates were cut to four plates with dimensions of 62´44´1.6 cm (length´width´ thickness) and longitudinal vibration test in PMD and MD were performed on each plates again. Finally, each plates were cut to samples with the dimensions of 36´1.6´1.6 cm and longitudinal vibration test and static bending test were measured. The results showed good correlation between dynamic modulus of elasticity from longitudinal vibration test and static modulus of elasticity and bending strength (result of beams extracted from each plates) in both sizes of the plates (in two size, 124´90´1.6 and 62´44´1.6 cm) and samples cut from each plates in two directions (PMD and MD). In addition, there was good correlation between dynamic modulus of elasticity of longitudinal vibration from two size plates (124´901.6 and 62´44´1.6 cm). When the samples were smaller, the dynamic modulus of elasticity values were increased, due to the diffusion of waves in samples with larger dimensions. In general, according to results of this research it can be concluded that by applying the appropriate correction factors, longitudinal vibration method can be an efficient method for calculation of dynamic and static modulus of elasticity and to estimate of the modulus of rupture in full size plates.

In this study, the effect of accelerated aging on adhesion strength of half-polyester and polyurethane transparent coatings were evaluated on maple wood (Acer velutinum) with the PH of 6 collected from north of Iran and pine wood (Pinus eldarica) with the pH of 5.5 collected from Russia. For this purpose, dried specimens with 12´110´550 millimeters size were used.Sealer as substrate, and half-polyester and binary polyurethane as coatings were applied on the wood. Coatings were applied by spray gun methods, and accelerated aging test of specimens was carried out according to ASTM D1037. Results indicated that maximum value of adhesion strength was determined on binary polyurethane in maple wood (Acer velutinum) and minimum for half-polyester in pine wood (Pinus eldarica). Also it was found that accelerated aging deteriorated the adhesion strength of coatings in both maple and pine woods.

The aim of this study was to investigate the effect of using different fillers in the presence of cationic rosin sizing agent on the properties of pulp and paper made from CMP fibers. For this purpose, cationic rosin internal sizing agent at the levels of 0, 0.5, 1 and 1.5 % based on oven dry weight of fibers, and fillers including grounded carbonate calcium (GCC), precipitated carbonate calcium (PCC), Talc and Zeolite in 25 % level based on oven weight of the paper accompanied with cationic polyacrylamide retention agent at the constant level of 0.3 % based on oven dry weight of fibers were added to the CMP pulp suspension according to the TAPPI standard. In order to examine the effect of different type of fillers in the presence of cationic rosin, handsheets with basis weight of about 60±3 g/m2 were prepared from each furnish. Then, various pulp and paper characteristics were measured. Statistical analysis of the results revealed that type of filler has dissimilar behavior on the pulp and paper properties in the presence of cationic rosin. Drainage time of pulp suspension was lower when adding Zeolite and GCC fillers. Talc and PCC showed more reduction effect on the paper strengths properties.Ultimately optical properties of papers improved more when Talc and PCC were added to the CMP pulp. Consequently, with respect to the priority of brightness and opacity for the copy and printing papers made from CMP fibers, addition of Talc and PCC in the presence of cationic rosin sizing agent may meet more the requirements compare to Zeolite and GCC fillers.

Production of test liner and fluting paper from old corrugated containers is one of the most common paper recycling processes in Iran. This type of papers are among the high basis weight papers and also contain significant fine fibrous and non-fibrous materials. Hence, the drainage and in addition, the retention of fine materials, are the obstacles for the paper mills. In these cases, usually application of drainage/retention aids, such as nanoparticle systems can be of good help. In this respect, colloidal silica and bentonite are the two most commonly used nanoparticles with polyelectrolytes in papermaking wet-end. Therefore, in this research, the effect of bentonite and silica sol nano-particles on the performance of cationic starch was compared in terms of drainability, retention and strength properties of paperboard from recycled old corrugated containers.The analysis of the particle size for these two nanoparticles showed that although the thickness of bentonite platelets (maximum 22 nm) was less than nanosilica dimensions (less than 50 nm), the effect of bentonite-cationic starch was not significant in terms of retention, against the nanosilica. Regarding the drainability, following dosing of both silica and bentonite, the parameter much improved (up to 186% in the case of nanosilica). On the other hand, application of cationic starch containing systems in paper hand sheets resulted in the improvement of tensile and tear indices. However, these properties decreased following addition of nano-particles. Also, internal bonding (Scott- type) incredibly increased (up to 354%) by application of cationic starch and nanosilica. Finally, generally in the case of OCC furnish, the nanosilica-cationic starch system had a better performance in terms of drainability, retention of fine materials and fiber fines and also strength properties, rather than cationic starch-bentonite.

Nowadays, recycled fibers are the main fiber source for the manufacturing of white top packaging papers. Sizing of such papers, based on the type of application, is of great importance. In this research, the effect of alum-cationic rosin consumption amount at the pH of about 6.5 on the properties of papers made from white sheets trimmings was examined. In order to optimize the consumption, pulp suspension sizing with alum in six levels of 0, 4, 5, 7, 8, and 10%, and rosin with the ratio of 50% of alum based on oven dry (OD) weight of pulp was applied according to the TAPPI standard methods. Then handsheets with basis weight of about 65±5 g/m2 were prepared and their Cobb test (45 second), structural and strength characteristics were measured. Statistical analysis of the results have shown that alum and rosin consumption of about 7 and 3.5% based on OD pulp is the suitable level for internal sizing of white trimmings fiber sheets. In these alum-rosin level, Cobb value of papers decreased from 120±11.6 g/m2 to the lowest value of about 64±9.7 g/m2. Contact angle of water droplet on the paper surface increased from 24.81o to 96.53o. Paper tensile index decreased up to 125±9.7 N.m/g by such sizing level and again increased with increasing alum-rosin level. Such phenomena can be attributed to the role of alum in charge neutralizing, cellulosic fines retention and improving bonding ability of paper network. Meaningful decrease of paper surface roughness from 10.34±0.54 mm in control sample to 8.23±1.37 mm in sized papers in optimized level confirmed at this assumption.

The potential of rose flower stalks for the production of particleboard was investigated. Three resin dosage gradients of 0, 2 and 4% (10% core: 10% surface; 9% core: 11% surface and 8% core: 12% surface) and three press times (3, 4 and 5 minutes) were selected as the variables and boards were produced. Then the mechanical and physical properties of the boards were measured and statistically analyzed. The results of modulus of rupture (MOR), modulus of elasticity (MOE) and internal bonding (IB) measurements showed that as the resin dosage gradient increases, these properties improved and boards produced using either 2 or 4% resin dosage gradients generated the highest values. The effect of resin dosage gradient on these properties was statistically significant. As the resin dosage gradient increases, both thickness swelling after 2 and 24 hour immersion in water was improved. The effect of press time on thickness swelling after 2 and 24 hour immersion in water was also statistically significant and these properties were improved when 5 minutes press time was used The results indicate that if 2 or 4% resin dosage gradients and either 4 or 5 minutes press time is applied for the manufacturing of particleboards using rose flower stalks residues, the specification of the boards will meet the EN specification.

Most of the fungicide that are used to prevent or terminate the biological deterioration of the historical papers have been used at the first time. So thiophanate methyl which is mostly used in agriculture, have been tested in repairing and protection of old papers. The main aim of this research was the assessment of aesthetic and structural effects on paper after treatment by thiophanate-methyl compound. Experimental method (laboratory experience) and library study were used in this research. ATR-FTIR spectra showed that thiophanate-methyl spray on paper did not produce any degradation effect. The compound had not changed aesthetical properties and pH values. Tensile strength of paper did not reduce due to the treatment. This indicates the nondestructive effects of thiophanate-methyl on paper which signifies its capability for application in conservation and restoration of paper.

The aim of this study was identification and comparison of chemical compounds in wood and bark of oak wood. For this purpose, the samples were selected randomly from oak wood in Nowshahr forest region. Then, flour and ash were prepared from heart wood, sap wood and bark of oak by TAPPI standards. For the measurement of metallic ions, first the mineral compound of ash was dissolved by 65% nitric acid and then identified by atomic adsorption method. The results showed that Fe, Zn and Cu ions in wood of oak were more than its bark and Mn ion was lower. Then extractives were separated from wood flour by acetone and these extractives were transferred to glassy vial and BSTFA was added to the reactor. The samples was injected to GC/MS for analyze. Identification of compounds was done by retention time of each compound, calculation of quartz index and Adams table. The result of GC-MS showed that there are 10, 42 and 10 compounds in heart wood, sap wood and bark of oak, respectively. Comparison of chromatograms showed that Decan, Dodecan, Tetradecane and Bis (2-ethylhexyl) phthalate exist as four common components in bark, sap wood and heart wood of oak and silicic acid and 1, 2-Benzenedicarboxylic acid exist as 2 common components in bark and sap wood of oak. These compounds are very important in durability and consumption of oak wood.

The effect of compounding process applying two methods of one and two step mixing on the properties of nanocomposite is investigated. Nanocomposites were produced using polypropylene, cellulosic fibers, MAPP and nanolay as reinforcement.1.5 and 3% MAPP and 0, 2, and 4% nanoclay were used as the variable factor and 20% fibers was used. Melt flow index was measured on compounds produced using one or two steps mixing. Each compound was mixed with fibers and MAPP and then the test specimens were made and tested according to ASTM test procedures. The results revealed that the two steps mixing increased the mechanical properties. The melt flow index of one step mixing was lower and the melt flow index of initial mixing of polypropylene with nanoclay was very high and it was reduced after compounding with fibers and MAPP. The results revealed that at higher dosages of the nanoclay tensile and bending modulus of the composite increased and tensile strength and modulus of rupture decreased.

Cellulose nanocrystals (CNC) are new class of cellulose materials that find wide applications in various research areas over the past two decades. These nanoparticles are usually made by acid hydrolysis of cellulose substances such as wood, cotton, starch etc. The main aim of this study was to find the optimal conditions for obtaining an aqueous stable colloid suspension of cellulose nanocrystal (CNC) from a-cellulose with a high-yield procedure. Therefore various conditions of acid hydrolysis were evaluated varying the reaction temperature and time. The percentage of yield was calculated for all suspensions. The morphology of the prepared CNC was characterized by Transmission Electron Microscopy (TEM), Environmental Scanning Electron Microscopy (ESEM) and the crystallinity was measured by X-ray diffraction (XRD). The results showed that highest yield of CNC (88%), was achieved applying the reaction condition of 60 minutes at 60oC. Generally, rod-like shape crystals from a-cellulose with an average size of 35-50 nm and high crystallinity (92%) can be produced as convenient and competitive source for the production of cellulose nanocrystal for various industries.