Iranian Journal of Wood and Paper Science Research
Year:2018 | Volume:33 | Issue:1 (62) |Papers Count:16

The aim of this study was to investigate the identification and comparison of chemical compounds in Alnus subcordata and Alnus glotinosa wood. For this purpose, the samples were chosen randomly from Alnus subcordata and Alnus glotinosa wood in Nowshahr's forest region. First, flour and acetone extractives were prepared using TAPPI standard test methods. Then, extractives were transferred to glass vial and was added BSTFA reactive agent was added. Then, samples were injected to the GC/MS device for analysis. Identification of compounds was based on retention time of each compound, calculation of Quats index and Adams table. The result of GC-MS showed that there exist 99 compounds in Alnus subcordata, including dibutyl phthalate (9. 15%), 2, 2-oxybis-ethanol (6. 62%), 1, 2-benzendicarboxylic acid (2. 63%) and squalene (0. 48%) were important compounds. In Alnus glotinosa, among 127 indentified compounds, butanedioic, monomethyl ester (10. 88%), isopropenoxypropan-2-ol (8. 82%), 3, 5-dioxaundecane (7. 73%), gamma-sitosterol (3. 53%) and vanillin (0. 39%) were important compounds. Comparison of chromatograms of the samples showed that there are 12 common components in Alnus subcordata and Alnus glotinosa, consisting of tetradecane, hexadecane, heptadecane, isopropenoxypropan-2-ol and bis (2-ethylhexyl) phthalate were important components. Some of these compounds can very important in durability and consumption Alnus subcordata and Alnus glotinosa wood.

In this research, the effect of adding precipitated calcium carbonate filler combined with nanocellulose as reinforcement was examined to compensate the strengths loss of papers made of bagasse pulp. About 2% of nanocellulose based on oven dry weight of fibers was suspended in water at 0. 1% consistency and was homogenized by ultrasonic, then was added to the pulp having 15% PCC filler. This mixture was compared with the same sample without adding nanocellulose and without any additives. Cationic polyacrylamide retention agent was added to the pulp suspension at the constant dosage of 0. 14% based on oven dry weight fibers. Statistical analysis of results revealed that the drainage time increased by adding of PCC and nanocellulose system to the bagasse pulp suspension. Addition of nanocellulose has increased filler particle retention due to the formation of adhesive flocs. Prepared SEM images from paper samples confirmed that filler particles flocculation, larger filler retention and their better distribution in paper network. Moreover, in papers filled with PCC and nanocellulose at roughly similar opacity and brightness, loss of strength characteristics due to addion of filler has been compensated. Although relatively higher drainage time of this pulp suspension is substantial limitation, but pretreatment of filler with nanocellulose prior to its addition to the pulp can be further investigated as a promising alternative.

Improvement of the strength properties of papers made from recycled fibers is one of the important aims in papermaking industries. Current research revealed that higher retention of strength inducing additives through alternative absorption of polymers having opposite charge is one of the promising approaches to obtain such purpose. In this study, treatment of fibers prepared from neutral sulfite semi-chemical papers with cationic starch and anionic CMC was conducted in pH~7, pH~10 and 0. 001 M NaCl suspension. Then, water retention value (WRV) and zeta potential of fiber suspension was measured. Standard hand sheets with 60± 3 g/m2 basis weight were made from untreated and treated pulps. The results have shown that WRV was significantly increased by absorbing of these two water-absorbing polymers. Consecutive changes of zeta potential confirmed charge reversion of fibers surface and sequential absorption of couple polymers. Scanning electron micrographs prepared from the samples of untreated and treated papers presented new changes in the degree of fibers bond area due to the larger absorption of these two reinforcement polymers. Moreover, considerable development in paper mechanical characteristics (tensile, burst and tear indices) proved the success of high absorption of applied bio-polymers.

In recent years, environmental problems of irregular wood harvesting and shortages of raw materials made wood and paper industry and country to be faced with serious crises. Some researchers and industry experts have been led to fundamental and long-term solution for supplying raw materials to these industries. The present study aimed to determine the optimum conditions of pulping and bleaching for three hardwood forest species (as a separate cooking & combined with 40% popular, 15% beech and 45% hornbeam) and paper evaluation. After preparing CMP at yield of 85%, applying cooking times (25-60 minutes, temperature of 170 ° C, the ratio of L: W of 7: 1 hand sheet with standard grammage of 60 g/m2 were made, Optical and mechanical properties of paper was evaluated. The results showed that, poplar wood were better in terms of total properties with mechanical and optical properties. Also in bleaching stage, the tensile strength index is decreased and burst and tear strength index was improved. The maximum initial brightness was related to poplar species wood and the beech wood had the lowest values. The opacity and yellowness either pure or combined wood pulps were decreased.

International trade has a significant share of the global economy andthe issue of regulating foreign economic relations is a major contributor to political talks in the countries. Social, political and cultural events, including political and economic agreements, imparts a tremendous impact on the trade of countries. Forests around the world produce large quantites of wood and trade in products throughout the world. Since Iran has been trading in wood with Russia and other European countries since about 100 years ago, this study was aimed at investigating the effects of political events on the bilateral exports of timber in Iran and Russia, as well as the effect of the Warsaw Treaty and its collapse on the wood trade of member countries with Iran was done using the gravity pattern. The results of the study showed that the Warsaw Pact as a political treaty affects the trade relations of the countries of the covenant with Iran, and the per capita income of two trade partners, exchange rate changes and geographical distances on the volume of wood trade and wood products have been effective. Results for both Iran and Russia showed the impact of wood trade on political events as well as domestic laws and bills approved by the two countries.

The purpose of present study was the use of Hemp stalks for particleboard production. Mixtures of Hemp stalk and Eucalyptus wood at the ratios of 0: 100, 50: 50, 100: 0 were used. Also two resin content of 8 and 10% (based on oven dry weight of particle) and 2 press times of 3 and 4 minutes were employed for the production of laboratory particleboard. The properties of laboratory boards such as thickness swelling after 2 and 24 hours soaking in water, modulus of rapture, modulus of elasticity and internal bonding were measured and data were statistically analyzed. It was observed that the increase in Hemp stalk particles in the mixture resulted in increasing of bending properties (bending strength and modulus of elasticity) and thickness swelling after 2 and 24 hours water soaking. Also the results showed that higher ratio of Hemp stalk particles in the mixture resulted in reduction of internal bonding. As expected, physical and mechanical properties of particleboard improved with increasing resin content. Modulus of elasticity and thickness swelling after 24 hours water soaking were improved with increasing of press time. In general, comparing the produced board mechanical properties with standard of Iran requirements, the board produced using either 100% or 50% Hemp stalk, 8% resin content and 3 minutes press time showed that optimal properties. The failure of the physical properties of the boards to meet the standard values can be due to the lack of use of paraffin.

Flexographic printing is the most applicable technology in the packaging industry. But the lack of proper adhesion of water-based ink on cardboard coated with polyethylene is one of the most important problems. Silane adhesion promoters are considered among the best compounds used as the crosslinking and waterproofing agents in coating and ink industries. In this study, N-(2-Aminoethyl) (3-aminopropyl) methyldimethoxysilane and 2-(3, 4-Epoxycyclohexyl) ethyl trie thoxy silane were used to improve the adhesion of water-based ink on paper board-coated with polyethylene. Results showed that highest degree of adhesion was achieved by adding 5% of N-(2-Aminoethyl) (3-aminopropyl) methyldimethoxysilane to ink. Adding silane compounds to ink formulation increased the contact angle of the ink film on the surface of cardboard coated with polyethylene which means that inks containing silane compounds act more successful in the formation of hydrophobic surface. It is worth noting that surface tension was decreased by addition of silane components to the formulation of the ink.

In this research, the bark extract of the yew (Taxus baccata L. ) tree trunk growing in AfraTakhte forest cache of Aliabad-e Katul) located in Golestan province was extracted with acetone solvent and Soxhlet apparatus method and then the chemical components of the extract were identified, Three disks with thickness of 50 cm were cut from the breast height of the three trees felled due to the wind and/the landslide. The bark of disks was separated and milled to the wood flour. Then, extract soluble in acetone was prepared according to TAPPI standard method. For the silylation of compounds, some dry powder of extract was poured into a glass vial and the derivative materials (pyridine, BSTFA + TMCS 1%) were added. Then, the sample was injected to the gas chromatography-mass spectrometry device. The results from research indicated that the mean value of acetone extract of yew bark was 13. 63%. Generally, 46 compounds were identified in the yew bark. The most abundant identified compounds were: tetrasiloxane, decamethyl-(14. 80%), hexadecanoic acid, hydroxy ester (11. 24%), 3-(3-aminopropyl)-6-(3, 3-dimethylallylamino)purine (9. 85%), d-ribofuranose, 1, 2, 3, 5-tetrakis-O-(hydroxy)-(9. 31%), 2-methylpyrrolo[1, 2-a]pyrazin-1(2H)-one (6. 73%). The various chemical components such as phenolic, flavenoid, alkaloid, fatty acid, fatty acid ester, sugar, alkane, fatty alcohol, alcoholic sugar, and stroied were identified in the acetone extract of yew bark that some of them can synthesized as preservatives for inhibition of wood-degrading organisms. The most important identified cytotoxic and anticancer compounds in the acetone extract of yew bark has been 4-piperidinone, 2, 2, 6, 6-tetramethyl-(0. 19%) and phenol, 2, 4-bis(1, 1-dimethylethy)-(3. 32%).

This research investigated the potential of acoustical Tomography and Imaging technology in the determination of the static strength of the urban standing trees to resist the forces exerted by heavy winds and tornados. First, locally made sensors and, micro-second timers and tomography images were compared with those of a certified European device in radial to tangential and longitudinal directions which showed good performance of Iranian made device. Having this technology available, the selected trees with the collar defect symptoms were initially inspected visually, then the visual accuracy was monitored by sonic tomography. While inspecting 103 trees, some were extremely defected internally, while the visual inspection showed their intactness (9 from 23). Afterward, some trees which showed having visually defect signs were proved to be intact after carrying the tomography images (up to 10 from 53). Therefore, it can be concluded that the visual tree defect inspection is not satisfactory for saving or eleminating the individual and these kinds of decision makings must be supported by the methods showing the hidden discontinuities or defects.

Radiography is a method of non-destructive evaluation of the quality of construction wood in order to detect the defects due to natural degradation. The objective of this study was to investigate the assessment of poplar (Populus deltoides) and beech (Fagus orientalis) wood defects arising from the decay using X-ray non-destructive method. In this study, for each of species, uncoated and coated by acid catalyzed lacquers and nitrocellulose lacquers samples were used. Decay resistance test was performed according to modified ASTM D1413 standard. The decaying of the woods was done for the periods of 1, 2 and 3 months using Coriolus versicolor fungus at laboratory conditions. After each of these periods, for the decay of the samples, X-ray imaging using an imaging at the cross, tangential, and radial directions was done. Results of weight loss confirmed the presence of decay. The results showed that after 1, 2 and 3 months of exposure to fungus, fungal degradation lead to weight loss in the coated and uncoated samples. So that, the weight loss caused by decay in beech was less than poplar samples. As well, the weight loss of uncoated was less than of coated samples, which was also statistically significant. The X-ray results of uncoated and coated samples at the cross, tangential, and radial directions indicated that decay has more impact on beech wood in comparison to poplar wood structure. The study as well showed that the protective layer provided a partly barrier for decay destruction in these samples.

The biodegradability of cellulose nananofiber-PVA nanocomposites were studied under controlled composting conditions and the quality of the compost was evaluated. The nanocomposite based on PVA with 5, 10, 20 and 30% wt of CNF was prepared by using liquid nitrogen and freeze drying techniques. Specimens were buried in compost obtained from municipal solid waste of a compost Factory, Karaj municipality, Iran, for 150 days. The biodegradability of materials was assessed by visual observation, weight loss, scanning electron microscopy (SEM) and chemistry and transparency (FTIR). The ecotoxicological impact of compost samples was evaluated via plant growth tests with cress and spinach. Biodegradation studies of the films during municipal solid waste confirmed that the biodegradation time of PVA/CNF films greatly depends on the CNF content. The SEM analysis showed that the biodegradability of the films at the surface of the samples (deep pores and cracks) was increased with increased the CNF content. By considering the ecotoxicological test using plants growth, it seems that all nanocomposite and pure PVA did not generate a negative effect on germination or development of the vegetal species.

This study was aimed to determine the modulus of elasticity and rupture of two types of date palms (varieties of Khasi and Hajmohammadi) woods using static bending and dynamic (flexural vibration) techniques. To reduce the difference between static and dynamic stiffness values, the static bending modulus of elasticity was modified by taking into account the value of the shear deflection. In addition, for better understanding of the mechanical properties of date palm, values were compared to those measured for poplar wood samples (Popolus deldtoides). The results showed that, the mean values of the modulus of elasticity obtained by flexural vibration, the static modulus of elasticity, the modified static modulus of elasticity and rapture of Khasi were 72, 105, 109 and 63% less than Hajmohammadi respectively. In comparison with date palm, values measured for poplar samples were more pronounced. The difference between dynamic and static values of modulus recorded for Khasi, Hajmohammadi and poplar samples were 81, 53 and 23% respectively. After modification of the static values, the reductions of difference were 14% for Khasi, 16% for Hajmohammadi and 9% for poplar wood samples. Finally, a high correlation was found between the static and dynamic modulus of elasticity for both kinds of date palms.

The present study was done with the aim of investigating the effect of heat treatment on chemical and physical properties of Iranian beech and Velvet maple woods. Results of spectroscopy showed that heat treatment led to decrease of hydroxyl groups which became more sensible with increasing temperature up to 175° C. Treatment at 190° C led to an increase of hydroxyl group comparing to the control ones. Increasing cellulose crystallinity, decreasing the hemicellulose content, increasing the lignin ratio, degradation of syringyl lignin and increasing the condensation reaction of lignin was also obtained from spectroscopy. Results of water absorption tests also showed that heat treatment decreased water absorption. The water repellency and anti-swelling efficiency for both species showed that heat treatment at 160° C didn’ t improve the water repellency and dimensional stability. However treatment at 190° C led to decrease of water absorbance especially in beech. In general, the effect of heat treatment on anti-swelling efficiency in beech wood was more pronounced comparing to acer, which can be explained by higher weight loss after heat treatment.