مجله تحقیقات علوم چوب و کاغذ ایران
سال سی و سوم شماره 1 (پیاپی 62، بهار 1397)

The aim of this study was accomplished on identification and comparison of chemical compounds in wood of Alnus subcordata and Alnus subglotinosa. For this purpose, the samples were chosen randomly from Alnus subcordata and Alnus subglotinosa in Nowshahr's forest region. So that, first, flour and extractives by acetone were provided by TAPPI standards methods. Then, extractives residue transferred to glass vial and was added BSTFA reactive agent to it. After prepared, samples were injected to the GC/MS device for it analysis. Identification of compounds was done by retention time of each compound, calculation of Quats index and Adams table. The result of GC-MS showed that there are 99 compounds in alnus subcordata, so that, 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 glutinosa, from 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 mention samples showed that there are 12 common components in Alnus subcordata and Alnus subglotinosa, that 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 subglotinosa.

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 fibers suspended in water with 0.1 % consistency homogenized by ultrasonic was added to the pulp having 15 % PCC filler and was compared with the same sample without nanocellulose and base pulp (without any additives). Cationic polyacrylamide retention agent was added to the pulp suspension at the constant level of 0.14 % based on oven dry 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 enlarged filler particle retention due to the formation of adhesive flocs. Prepared SEM images from paper samples confirm filler particles flocculation, larger filler retention and their better distribution in paper network. Moreover, in papers filled by PCC and nanocellulose with roughly equal similar opacity and brightness, loss of strength characteristics due to adding of filler has been compensated. Although relatively higher drainage time of this pulp suspension is a substantial limitation, but pretreatment of filler with nanocellulose prior to its addition to the pulp can be investigated as a promising alternative.

Improvement the strength properties of papers made from recycled fibers is of important aims in papermaking industries. Current researches revealed that higher retention of strength induced additives through alternative absorption of polymers having opposite charge is one of 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 salty suspension. Then, fibers water retention value and zeta potential was measured. Standard handsheets with 60±3 g/m2 basis weight were made from untreated and treated pulps. The results have shown that fibers WRV significantly increased by absorbing of these two water-loving 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 variations in amount of fibers bend 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 Ind. & country to be faced serious crises. And some researchers and industry experts have led to fundamental and long-term solution for supplying raw materials to these industries. This present study aimed to determine the optimum conditions of pulping and bleaching for several hardwood forest species (as a separate cooking & Combining with 40% popular, 15% beech and hornbeam 45%) and paper evaluation. After preparing CMP in accordance with the terms of an 85% efficiency , Different cooking times (25-60 minutes, temperature of 170 °C, the ratio of L TO W & 7 TO 1 and Making hand sheet with standard 60 gram per square meter, Optical and mechanical properties of paper was evaluated. The results showed that, A species that was used in cooking, Poplar were better in terms of total properties with mechanical and optical properties. Also in Bleaching stage, the tensile strength index is decreased & Burst and tear strength index is improved. The maximum brightness is related to poplar species with mixing and without species and after bleaching the beech is the lowest ones. In both methods the rate of opacity and yellowness is decreased.

International trade has a significant share of the global economy; the 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, have a tremendous impact on the trade of countries. Forests around the world produce large amounts of wood and trade in products throughout the world. Since Iran has been trading in wood with Russia and other European countries 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 show 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 show the impact of wood trade on political events as well as domestic laws and bills approved by the two countries.

The purpose of this study was to use of Hemp stalks in 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 particle) and 2 press times of 3 and 4 minutes were employed for the production of laboratory particleboard. Physical and mechanical properties including thickness swelling after 2 and 24 hours soaking in water, modulus of rapture, modulus of elasticity and internal bonding were measured 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 increase in 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 100% and 50% Hemp stalk, 8% resin content and 3 minutes press time showed that optimal properties. Although the physical properties of the boards did not meet the standard values, the reason for this could not be due to the lack of use of paraffin.

Flexographic printing is the most usable 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) ethyltriethoxysilane were used to improve the adhesion of water-based ink on paper boarded-coated with polyethylene. Results showed that highest amount of adhesion were 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 grow in AfraTakhte forest cache of Aliabad-e Katul) located in Golestan province was extracted with acetone solvent and by Soxhlet apparatus method and then the chemical components within it were identified. The bark of prepared disks was separated and converted to the flour. Afterwards, extract insoluble acetone solvent was prepared according to TAPPI standard method. In order to silylation of compounds, amount of dry powder of extract was poured into a glass vial and the derivative materials (pyridine, BSTFA TMCS 1%) were added to it and to identification the sample was injected to the gas chromatography- mass spectrometry device. The results from this 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 including: 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%).

Reaching to the technology of acoustical Tomography and imaging, this project was ordered for facilitating the work for green space researchers and managers in urban standing trees. Comparing the sensors and micro-second timers with those of a certified European device in radial to tangential and longitudinal directions showed a good agreement for the Iranian made device. So, a new horizon was opened for the researchers of this approach supported by the local scientific knowledge and technology. Holding this technology, the selected trees concerning the collar defect symptoms were firstly inspected visually, then the visual accuracy was monitored by sonic tomography. Some trees were extremely defected internally, while the visual inspection showed their intactness (9 from 23). Meanwhile some trees holding visually defect signs were proved to be intact after carrying the tomography images (up to 10 from 53). It is concluded that the visual tree defect inspection is not satisfactory for saving or omitting the individual and these kinds of decision makings must be supported by the methods showing the hidden discontinuities.

Radiography is a method of non-destructive for evaluating the quality of wood construction machinery 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 decaying by using x-ray non-destructive method. In this study, for each of species, uncolored (no coating) and colored samples by acid catalyzed lacquers and nitrocellulose lacquers were used. Decay resistance test based on modified ASTM D1413 standard was performed. The decay process was done in the periods of 1, 2 and 3 months with use of Coriolus versicolor fungus at laboratory condition. After each of these periods, for the decay of the samples, x-ray imaging by using an imaging at the lateral, tangential and radial direction was done. Results of weight loss confirmed the presence of decay in the radiographic images. The results showed that after 1, 2 and 3 months of exposure to fungus, fungal degradation leads to weight loss in the painted and unpainted samples. So that, the weight loss caused by decay in beech was less than poplar samples. As well, the weight loss of unpainted was less than painted samples, which was also statistically significant. The x-ray results of unpainted and painted samples at the cross, tangential and radial directions indicate that decay has a more impact on beech in comparison to poplar wood structure. The study as well showed that the protective layer has partly a 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 calculation the 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 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.

The goal of this study was to determine the modulus of elasticity and modulus of rapture of two kinds of date palm (Khasi and Hajmohammadi) 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 to, for better understanding of the mechanical properties of date palm, values were compared with those measured for poplar samples. The results showed that, in Khasi the mean values of the modulus of elasticity obtained by flexural vibration, the static modulus of elasticity, the modified static modulus of elasticity and as well as the modulus of rapture were 47, 67,68 and 38% less than those measured for Hajmohammadi respectively. In comparing 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 63, 40 and 19% respectively. After modification of the static values, the difference was reduced in to 3% for Khasi, 6% for Hajmohammadi and 7 % for poplar experimental samples. Finally the significant correlation coefficients were found between the static and the dynamic modulus of elasticity for both two kinds of date palm.

The present study was done with the aim of investigation of the effect of heat treatment on chemical and physical properties of Iranian beech and Velvet maple. Results of spectroscopy showed that heat treatment led to decrease of hydroxyl groups which became more sensible with increasing temperature up to 175oC. Treatment at 190oC 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 increase the condensation reaction of lignin was also obtained from spectroscopy. Results of water absorption tests also showed that heat treatment caused decreasing of water absorption. The water repellent and anti-swelling efficiency for both species showed that heat treatment at 160oC didn’t improve the water repellency and dimensional stability however treatment at 190oC led to decrease of water absorbance specially in beech. In total, the effect of heat treatment on anti-swelling efficiency in beech was more considerable comparing to acer, which can be explained by higher weight loss after heat treatment.