Iranian Journal of Wood and Paper Science Research
Year:2021 | Volume:36 | Issue:1 (74)|Papers Count:7

In this study, the effect of adding used tire rubber (UTR) on the physical and mechanical properties of OSB produced from Paulownia wood strands was investigated. Constant factors of this research are: strands of paulownia wood with the dimensions of 0. 20 × 0. 8 × 120 mm, phenol formaldehyde resin (8% based on dry weight of strands and used tire powder was enriched with 10% resin based on dry weight of tire powder). Laboratory boards with a thickness of 17 mm, dimensions of 40 × 40 cm with a nominal density of 0. 5 g cm3, pressing time of 10 minutes and the pressing temperature of 180 ° C. The 3 layers OSB consisting of top and bottom layer (25%), and middle layer (50% by weight was produced). Variable factors are: the amount of tire powder (10, 20 and 30%) and the distribution of tire powder particles in 3 layers was in the surface layers, in the middle layer and in all three layers. The mechanical and physical properties of the boards were measured as defined in relevant European standards test methods EN 300. The results of physical properties showed that increasing the used tire powder improved the thickness swelling of the boards and the minimum value of thickness swelling was observed in the dosage of maximum used tire powder of 30% and scattered in all three layers. The highest values of mechanical strength was observed in panels made of 10% used tire powder, and the highest value of MOR was reached at the dosage of 10% used tire powder and scattered in all three layers and the highest value of MOE and IB at the same level of used tire powder dosage distributed in the surface layers.

In this study, the possibility of making gypsum-based boards using different levels of rice straw chips was investigated. Variable factors in this study were nano-wollastonite at three levels of 0, 3 and 7% and also the ratio of rice straw to gypsum at three levels (5: 95, 10: 90, 15: 85%). Thus, with the consideration of nine treatments, a total of 27 laboratory boards were produced. The target density of 1. 10 gr/cm3 was considered. Mechanical and physical properties of composites including modulus of rupture, modulus of elasticity, internal bonding, water absorption after 2 and 24 hours of immersion, and density of boards were measured according to DIN-EN-634 and fire resistance (weight loss percentage) according to ISO-11925. In order to investigate the bonding potential between rice straw and gypsum as well as the distribution of nano-wollastonite, electron microscopic images (SEM) of the fracture surface of the samples were produced. The results showed that the composites made with nano-wollastonite possessed that higher mechanical and physical strengths. Microscopic imaging (SEM) showed that the boards made with 7% nano exhibited more extensive internal bonds and created a uniform structure. In this study, composites made of 7% nano wollastonite with 5% rice straw were selected as the optimal treatment.

Tamarisk is a drought-resistant tree that is environmentally important and has industrial applications in some countries. The aim of this study was to compare different populations of this species in terms of diameter growth rate (growth ring width), physiological adaptability (vascular characteristics) and wood application characteristics (fiber biometry). The study was conducted on ten-year-old saplings of six tamarisk populations that was previously collected from different regions of Iran (Qom, Kashan, Khash, Zabol, Garmsar and Yazd) and planted in Garmsar. The results showed that Garmsar population has the largest diameter and radial growth among populations. This population was chosen as the best strategy for adapting to cold and dry climates by keeping the vessels small and significantly increase their number, instead. This has been the reason for its better radial growth. Although the biometric properties of fibers and paper ratios showed significant statistical differences between populations, but these differences were not so great as to have a significant impact on the quality of the resulting paper in practice. Therefore, although the population of Yazd was of better quality in terms of paper parameters, the selection of the best population for industry should not be only based on fiber biometry and other features such as production volume, adaptability to habitat and survival rate of seedlings should be given more importance. The positive correlation between the width of the growth rings and the length of the fibers from the perspective of wood cultivation is very favorable because the treatments that increase the growth rate will also improve the fiber properties. In general, it can be concluded that Garmsar population is the best option for planting and cultivating tamarisk in terms of adaptability to environment and wood farming.

Kenaf as an industrial plant can play an important role in providing shortage of virgin fiber for paper and board paper based on the history of cultivation in Iran. Harvesting time of kenaf is one of the most important economic-technical aspect. So the growth rate of kenaf (variety of Cuba) and the weight ratio of bast, core and pith individually were measured at 5, 6 and 7 months after planting and kenaf biomass was determined after 7 month. Soda-AQ pulping variables of kenaf bast fiber was selected at 14% and 16% chemical charges, 175° C, time; 120 min., liquor to bast fiber of 5: 1 and adding 0. 2% AQ. Handsheet was made from bast pulp collected from three harvesting times with base weight of 110 g/m2. The results showed that by increasing the harvesting period from 5 to 6 and 7 months, stalk height and diameter increased by 9% and 5%, respectively. The weight ratio of kenaf bast to core has decreased by increasing of harvesting time. Dry and green biomass of kenaf was determined at 33. 1 and 7. 7 t/ha, respectively. Pulping screen yield, kappa number, and reject were measured for combinations of optimal cooking in range of 48. 8% to 52. 9%, 35. 4 to 72. 6, and 0. 92% to 2. 5%, respectively. The beating energy consumption of pulp prepared from 7 month harvesting time was greater than the others. Optimal conditions were determined as harvesting time of 5 month and cooking variables of 120 min, 175 ° C and 16% NaOH for carton top liner. Handmade paper properties was compared to kraft liner paper confirms the superiority of paper made from virgin kenaf bast fiber according to national standard of Iran (ISIRI 3054).

In the present study, the properties of medium-density fiberboard made with urea formaldehyde resin as a control sample and compared with MDF made using chitosan and carboxylic acids were investigated. Various compounds including chitosan acetate solution, chitosan acetate – butane tetra carboxylic acid solution, chitosan acetate-citric acid solution and citric acid solution were investigated. The chemical structure of specimens was investigated by Fourier transformed infrared spectroscopy (FTIR). The results of spectroscopy clearly showed the difference in the use of different compounds. The formation of cross-links between cellulose chains and carboxylic acids was confirmed, as well as the formation of hydrogen bonds between chitosan and lignin. Specimens made with the combination of acetate chitosan-BTCA showed better dimensional stability and the internal bonding of MDF specimens made with chitosan acetate solution was higher than controls. Chitosan acetate-BTCA compound can be considered as a successful substitute for urea-formaldehyde adhesive due better dimensional stability and good internal bonding of the fiberboards.

In this study, ammonium hydrogen sulfate immobilized on Luffa fruit (AHS@L) as an effective and biodegradable solid acid catalyst was synthesized by acidification of Luffa fruit via a new method. The synthesized catalyst was characterized by TGA, SEM, XRD and FTIR. The FT-IR analyze approved the acidification of the Luffa surface by hydrogen sulfate moieties. Also the XRD analyze clearly show the change in the morphology of Luffa after acidification. The TGA analyze show the heat resistance of the catalyst up to 245 ° C and the FESEM images clearly showed that the catalyst surface was hydrated as a result of acidification. The synthesized catalyst was used to protect the amines in the N-tert butyl carbamate reaction under solvent-free conditions at room temperature. Different types of aliphatic and aromatic amines have been produced as related monocarbamates with excellent yields and short reaction times. This method was mild and selective and has advantages such as heterogeneous catalysis, low cost and catalyst recovery capability.

In this study, the effect of cellulose nanofibers and silicon nanoparticles on the properties of nanocomposites made with polyvinyl alcohol was studied and the physical, mechanical and morphological properties of nanocomposites were measured. Samples were prepared by casting with different ratios of 0, 5 and 10% by weight polyvinyl alcohol. The morphology of nanocomposites was examined by scanning electron microscopy. Observations of water vapor permeability and water uptake by adding cellulose and nano-fiber nanofibers in pure polyvinyl alcohol control film and nanocomposite films with different compositions were significantly different from each other. The tensile strength of nanocomposites showed that by increasing the amount of cellulose nanofibers and silicon nanoparticles, the tensile strength increased and the percentage increase in length decreased by adding cellulose nanofibers and silicon nanoparticles. The results of the present study show that the addition of small amounts of nanocellulose fibers and silicon nanoparticles strengthens the polyvinyl alcohol polymer and improves the physical and mechanical properties and increases the performance of nanocomposites.