مجله تحقیقات علوم چوب و کاغذ ایران
سال سی و هفتم شماره 3 (پیاپی 80، پاییز 1401)

The strength properties of medium corrugated board which is made using recycled pulp are always important. The aim of this study was to investigate the effect of bulking agent’s addition and acetylated starch on the strength properties of corrugated board from neutral sulfite semi-chemical and old corrugated container pulp. For this purpose, the pulp was treated with two materials separately including tri (propylene glycol) butyl ether and di (propylene glycol) butyl ether bulking agents in the 0.9% dry weight of the pulp level. In addition, each of these bulking agents was added with acetylated starch (at the level of 4% of dry weight of the pulp) to the pulp suspension. The strengths properties of corrugated board were measured. The results showed that the corrugated board treated by tri (propylene glycol) butyl ether and di (propylene glycol) butyl ether bulking agents had the highest bulk and thickness in comparison to other samples. Also, the strength properties of samples decreased by adding bulking agents. Acetylated starch was used to improve the strengths of samples. Addition of acetylated starch with bulking agents improved the strengths of samples. Corrugated board with tri (propylene glycol) butyl ether and acetylated starch showed highest tensile, burst, tear strengths, stiffness, CMT and RCT. Results showed that the effect of different treatments is statistically significant in all trials.

This study was carried out to compare the individual and combined effects of nanolignocelluloses (NLC), cationic polyacrylamide (CPAM), cationic starch (CS) and imported chemical long fiber (LF) in the manufacture of recycle liner and fluting paper for packaging. Individual treatments of OCC were included 15% LF, 6% NLC, 1.5% CS and 0.15% CPAM as addetives. Combined treatments were included 6% NLC and 1.5% CS, 6% NLC and 0.15% CPAM. Handsheets were made with grammage of 127 g/m2 by application the mentioned treatments. Finally, the physical, mechanical properties and microscopic structure of handsheet were investigated. The results showed that addition of LF and NLC caused the density of handsheets decreased compared to the control. The individual and combined treatments led to increasing the tensile and burst strength of handsheet. Also, the tear strength of handsheet increased compared to the control except for the combined treatment of NLC and CS. FE-SEM images showed pores relative reduction in handsheet that prepared from combination treatments. It showed negative effect on water drainage. The addition of 6% NLC and 0.15% CPAM to OCC pulp resulted in the highest crush strengths as RCT and CMT compared to the control. SEM micrographs showed relatively reduced pores in handsheets prepared from combined treatments, which could have negative effect on the dewatering of OCC pulp.

In this study, ground penetration radar (GPR) was used to assess the internal defects and decay of structural old timber in buildings and compare it with the sound wood. For this purpose, twelve samples of three wood species of beech, oak and yew with dimensions of 120 × 60 × 400 mm, and as flat sawn were selected. Two samples from beech species with severe decay and two samples from oak species with mild decay were selected from old buildings. Sound and completely dry samples of these species (two samples from each species) were also obtained from forest trees as an indicator. Four yew samples without decay were selected only from the old buildings. Holes with a diameter of 2 and 8 mm were drilled in decayed and also two yew samples. The samples were scanned perpendicular to the fibers direction using a HF antenna of 2.3 GHz. The condition of data collection and processing were the same for all samples. After the initial data collection, in order to increase the resolution and better interpretation of the image, different filtration process was applied using image processing software Reflexw. The results showed that the relative dielectric coefficient was higher in decayed wood, and due to the difference in reflection coefficient between sound and decayed wood, they can be distinguished from each other. It was also possible to detect holes of 8 mm in oak and yew species.

Sycamore tree (Platanus orientalis) is one of the species that planted in parks and urban green spaces and forests region of Tehran and other cities in Iran. The aim of this study was to identify and compare the phenolic chemical components ‎in wood and bark of planted sycamore tree. In this study, three trees were randomly selected and felled in planted forest region of Tehran. Three disks were prepared from each tree and according to TAPPI standard tests, first wood flour and then the extractive ‎(%) were separated from wood flour using acetone solvent. To‏ ‏identify of extractives, about 1mg extractives was ‎mixed with 30 microliters BSTFA and the samples were analyzed using a gas chromatograph connected to mass spectrometry (MS) with a detector. Samples were then injected into the injection section of GC/MS using a Hamilton syringe. The compounds identification was performed using GC diagrams, ‎abundance and retention time of each compound, calculation of quartz index and Adams table. The results showed that the average of extractives in wood and bark of the planted oriental plane tree were 3.6 and 16.6 percent, respectively. GC-MS results showed that 17 specification compounds were found in ‎the plane wood. Furthermore, Hexadecanoic acid (22.18%), Heptadecan-8-carbonic acid (15.24%), and 1, 2-Benzenedicarboxylic acid (12.08%) were the most important ‎ compounds. The 41 compounds were identified in the plane bark that 9-Octadecanoic acid (19.88%), n-Hexandecanoic acid (16.41%), 9, 12-Octadecanoic acid (9.66%) and Gamma-Sitosterol (2.09%) were the most important compounds. In addition, the results showed that 9-Octadecanoic acid, Hexadecane, Dodecan, Tetradecan, Eicosan, Octadecane, and Decane were the 6 common compounds in the wood and bark of sycamore tree, as well

Researches on antimicrobial coatings to protect surfaces from remnants of microorganisms on the surfaces in the environment that can lead to the spread of diseases in human societies, has attracted a remarkable interest. In this regard, the effects of chitosan nanofibers and clay nanoparticles (sodium montmorillonite) on antibacterial properties of melamine coatings were investigated. Urea formaldehyde and melamine formaldehyde resins were prepared by adding nanomaterials to each of them 1% by weight using a mechanical-ultrasound mixing method. The distribution and presence of nanomaterials in the resin and the antibacterial properties of melamine coatings were studied. To investigate the antibacterial properties of melamine coatings prepared, two type Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) were used. The results of X-ray diffraction and field-emission electron microscopy images, confirmed the proper distribution of chitosan nanofibers and clay nanoparticles in the polymer. The results also showed that by adding nanomaterials to the resins used in the melamine coating, the antibacterial properties of the coatings can be remarkably improved. On the other hand, the study of antibacterial properties of coatings showed that chitosan nanofibers had stronger antibacterial properties than clay montmorillonite Na+ nanoparticles.

Presently, because of the human health issues related to the formaldehyde gas emission initiated from traditional wood adhesives like urea formaldehyde, the bio-sbased adhesives has shown a good solution for preventing health hazards for human and the environment. To achieve an acceptable approach in wood based composites production, these adhesive need to qualify different standard limitations. This research was conducted to improve the bio-based soy-tannin adhesive for producing plywood with acceptable properties. For this goal, different adhesive formulations were prepared in the laboratory and they were treated at different temperature (40, 60, 80 ºC). Poplar wood plies with 2 mm nominal thickness were used to produce plywood specimens. The results showed the effectiveness of adhesives with heat pre-treatments at different temperature on shear strength (dry and wet) of plywood specimens. The highest shear strength of plywood specimens was achieved for 40 ºC treated adhesive in both dry and wet condition. Based on the results of shear strength test, all manufactured plywood specimens successfully met EN-314-2 standards requirement. Also, the results of delamination test revealed that plywood specimens which prepared by 40 ºC treated adhesive can successfully use for indoor condition, based on ANSI-HPV-1 requirements.

This study aimed to identify and compare the chemical components of organic matter in the leaves of ‎the planted elder pine (Pinus eldarica) and sycamore (Platanus orientalis) tree using gas chromatography and mass spectrometry techniques. In this study, 20 samples from leaves of eldar pine and sycamore trees were randomly selected from ‎the planted forest area of Tehran city. To prepare a homogenous sample (leaf flour), the leaves were thoroughly mixed and then ‎the extractive was measured according to TAPPI standards. The results showed that the average of extractives in the leaves of the planted Elder pine and sycamore tree ‎were 16.2 and 14.4%, respectively. In addition, the leaf flour was extracted with acetone. ‎The remaining extractives were then added to the BSTFA reactor. Then, the samples were placed in heated Bath (70oC, 1h.), and were finally analyzed by GC/MS. The GC diagram (indicates the abundance and retention ‎time of each compound) and calculation of quartz index, and Adams table were used to identify the compounds. The result showed that there were 20 compounds in the leaves of the plane tree that n-Hexadecanoic ‎acid (24.28%), Heptadecan-8-carbonic acid(18.05%), Octadecanoic acid (14.1%), and E Vitamin (2.81%)  ‎were the most important compounds. 45 compounds were identified in the leaves of the planted elder pine tree in which 9,12,15-Octadecatrien-1-ol (11.49%), ‎‎4-Methylmannose (10.68%), Mome Inositol(9.65%), and Phytol (0.64) were the most important compounds. Additionally, 5 combinations of Decan, Dodecan, Neophytadiene, and Octadecanoic acid were common between ‎the leaves of planted elder pine and plane tree.