Iranian Journal of Wood and Paper Science Research
Year:2014 | Volume:29 | Issue:1|Papers Count:19

The influence of fiber lignin content and the dosage of coupling agent on the strength and physical properties of cellulosic fiber-polypropylene composite were investigated. The old corrugated container (OCC) fibers were delignified using sodium hydroxide to reach the lignin content of 2.7, 3.78, 5.26 and 7%. Fibers were compounded with polypropylene by extrusion process using 20% fibers and 77% PP and the extrudate was cooled and grinded to fine granulates before injection molding. MAPP coupling agent was applied at three different levels (1, 2 and 3 percent based on the total weight of the composite). The strength properties of the composites were measured using relevant ASTM test methods and the results were statistically analyzed using factorial experiment under complete randomized design. The impact of fiber lignin content of flexural strength of composite was statistically significant at 98 percent significance level and the lowest and highest values of flexural strength of composite were measured at 3.78 percent and 7 percent lignin content of fiber. The interactive effect of fiber lignin and MAPP on the tensile strength and flexural modulus of elasticity of the composite showed that at lower values of lignin and higher dosage of MAPP, these properties are 38.7 and 3438 MPa respectively. Other strength values of the composites were also improved and at lower content of lignin and increaing dosages of the MAPP, the impact strength of the composites was increased from 52.82 J/m to 60.26 J/m.

In present competitive world, packaging has a significant effect on the rate of sale. Unfortunately, in Iran’s packaging industry, the variation of printing methods is too low which leads to reduction in quality of packing and the amount of sale. Therefore, some manufactures prefer to send out their products to be packed. In this paper, to achieve an acceptable quality in printing the paper packaging, four factors of paper roughness, ink viscosity, grindometer (unresolved droplets of ink particles) ink and paper thickness were studied. Fractional factorial designs are used to evaluate the factors. Each factor is investigated in two levels. Based on obtained results, all the factors have a significant impact on response.

The objective of the present study was the utilization of rose flower residues for the production of medium density fiberboard. MDF was produced applying two moisture gradients of 0 and 4% between surface and core layer, two press temperatures of 175 and 185°C and three pressing times of 3,4 and 5 minutes. The mechanical and physical properties of the boards were measured and statistically analyzed using factorial experiment and complete randomized design. In case statistical difference was observed between the averages, then Duncn multiple range test was used for grouping of the averages. The results revealed that the moisture gradient statistically influenced the flexural strength and internal bonding of the boards. In both moisture gradients, the internal bond of the boards increased and the maximum was reached when 5 minutes pressing time was applied. The pressing time also statistically influenced the thickness swelling and the lowest values were measured on boards pressed for five minutes. Generally, the strength properties of the boards were in accordance with the required specification of EN standard, which indicates that rose flower residue can be considered as a suitable raw material for medium density fiberboard production.

Cereal straws including grain sorghum varieties can be used for pulp production due to the significant amount of residual straw after harvesting. This study showed that there are no significant differences between fiber dimension and papermaking coefficients of two varieties of sorghum (Kimia and Sepideh). The average of fiber length, fiber width, lumen diameter, and cell wall thickness were measured as 1.19 mm, 23.20, 15.34, and 3.93 mm, respectively. Significant difference (P<0.05) was found among all chemical composition of two varieties except lignin content. The average content of holocellulose, alpha-cellulose, lignin, extractive, and ash were determined as 62.13%, 37.71%, 21.05%, 9.58% and 6.97%, respectively. The result revealed that pulp strength produced from Sepideh variety was better. However it requires more intense delignification compared to Kimia variety. The highest screen yield (33.19%) was reached applying the treatment combination of 170°C, 12% NaOH, and 75 minutes from the Sepideh variety. Sorghum pulp could be combined with the virgin pulp to compensate cellulose raw material shortage in paper industry.

Imported lumber of Norway spruce called European spruce (Picea abies L.) from Russia have a variety of applications. However, the presence of fungal agents in this wood, their application is limited. In addition, some the fungi associated with these woods are able to cause disease in human. In order to identify the presence of such fungi in the imported woods from Russia, samples were collected from Asalem region. Isolation and preparation of pure colonies of fungi grown on woods was done using ascosporic or conidial mass suspensions and single spore method. The morphological characteristics of fungi grown on wood pieces and on culture media were studied using light microscope. The results showed that Ophiostoma piceae in sexual phase and Sporothrix sp. and Graphium spp. in asexual phase are present in these woods. In the culture, Ophiostoma sp. with asexual stage of Sporothrix sp. and Ceratocystis sp. With asexual stage of Chalara spp. was identified. The results of microscopic examination of woods in cross and radial sections showed that fungal hypha penetrated the resin canals, the ray parenchyma, tracheids, and cross-field areas.

Tobacco (Nicotianan tabacum) is the main plant to supply tobacco leaf as the raw material for a major industrial establishment in north of Iran. Therefore a substantial volume of tobacco stem is produced in this region. In this research, stems of tobacco variety Coker 347 was randomly collected from the, city of Astara, Gilan province and the samples were prepared according to the TAPPI standard test. The stem flour was prepared and extractives were determined. The results showed that the mean extractive content of tobacco variety, Coker 347 is 10.41 percent. Then extractive soluble in toluene - ethanol (v/v 2:1) were separated. Extractive were collected in a glass vial and the BSTFA reagent was added. Samples were stored for one hour at room temperature and 70°C in a water bath and then were analyzed by GC / MS. A total of 11 chemical compounds in tobacco stem wood extractives variety Coker 347 were identified with different percentages. These compounds include, P- Prydyn, 1– tri methyl Saylyl, 1, 2- benzene di- carboxyl acid, alpha -D- Golokopyranoz, 11, 8– di methyl - 13- (4- aksu -1 - methyl), tri Floyver methyl isopropyl sulfide which show the highest values.

Member joints and furniture designs are very important in the production of these elements and the strength of the structure is affected by both the joints and designs. The performance of the chairs made from poplar wood against the front to back load test and also, mechanical strength of mortise and tenon and dowel joints were evaluated and compared. Two types common wooden chairs having side stretcher or without side stretcher, and also the chairs structured by common joints and poly vinyl acetate (PVA) adhesive are evaluated and their maximum strength were measured. The results showed that treatments and intercept treatments were statistically significant with the 95% confidence. Duncan analysis for comparison of the averages showed that maximum load of different treatments can be classified into four category; A; Pattern of side stretcher with mortise and tenon joint (984.5 N), B; Pattern of side stretcher with dowel joint (892.4 N), C; Pattern without side stretcher with mortise and tenon joint (303.3 N), D; Pattern without side stretcher with dowel joint (260.2 N). Since, all treatments showed statistically significant differences, it can be conclude that the maximum strength of the chairs is significantly influenced by the pattern of side stretcher and the other factor is the mortise and tenon joint.

In this study lignin from unbleached hardwoods chemimechanical pulp was extracted and the chromophor functional groups of the lignin were studied. Acetylation and reduction treatments were perfomed and samples were analyzed by FT-IR spectroscopy. A mild acidic dioxin extraction method was employed to isolate lignin. For the acetylation and reduction treatments of lignin acetic acid and sodium borohydride were used respectively. The results of untreated and treated (acetylated and reduced) lignin spectra showed that, the major of lignin chromophor groups such as hydroxyl and carbonyl groups have been reduced or eliminated by these treatments. In the acetylated lignin, the absorption band of hydroxyl groups has been weakened and in the 1743.16 Cm-1 region, acetoxy compounds band has appeared and also a cluster absorption band was observed in the 1228.76 Cm-1 region. In the reduced lignin, most of the absorption bands of the carbonyl groups have been weakened or eliminated, especially in the 1705.56 and 1629.54 Cm-1 region.

The objectives of research were to create tree ring chronology of juniper trees and investigation on the relationship between the growth rate of the tree and the climate. Juniper trees are naturally distributed in High Mountain with semi-arid and arctic climate condition of Iran. Samples were collected from 20 trees in Shah-Kouh Mountain with 54° 42´ 58˝ longitude and 36° 61´ 01˝ latitude coordinate. Increment core were prepared and analyzed. The time span for tree ring chronology was 271 year (1741-2012 AD). Tree ring chronology statistic for MS, EPS, SNR, were 5.6, 0.85, 0.29 respectively. Correlation between tree ring index and climate data showed that mean temperature in the previous growing season is an important factor for growth of juniper trees. The result of this research can help the development of climate data and is useful for the creation of weather atlas.

The suitability of using Iranian grown giant milkweed fibers (GFs) as a new raw material for thermoplastic composites was investigated. The polypropylene (PP) was used as the matrix polymer and the maleated polypropylene, Epolene G- 3003TM, was used as coupling agent. In the sample preparation, four levels of fiber loading (10, 20, 30, and 40 wt%) and three levels of coupling agent content (0, 1.5, and 3 wt%) were applied and the mechanical properties of composites are analyzed. GF/PP composites were prepared by a melt compounding process in a twin-screw extruder followed by injection molding. The results showed that with the addition of coupling agent, both tensile and flexural properties improved considerably compared with control specimens (without coupling agent). As expected, notched Izod impact strength was significantly decreased as the mixing ratio of fiber increased. The results of the present study revealed that composites with good strength properties could be successfully developed using GF as the reinforcing agent. The Heat Deflection Temperature (HDT) is determined following the test procedure outlined in ASTM. High HDT in this study showed that coupling agent at3 wt% and fiber loadiny either 30 or 40 wt% were superior compared with other treatments.

In recent years, one of the most important reason for increasing consumption and consequently demand for the imports of all types of paper products can be the increase in gross domestic product. Therefore in this research, the relationship between consumption, demand for imports of fine paper and economic growth have been investigated using annual time series data in the period of 1984 to 2010.Since the time series are non-stationary (Unit root) and can lead to spurious regression, the stationary of the variables are investigated in its logarithmic form using Augmented Dickey Fuller test (ADF) in two type of intercept; without trend and intercept with trend. After applying the unit root test, in order to understand the interaction between economic growth and consumption and imports of fine papers and direction of the causal relation, the vector auto regressive (VAR) approach including two models and the causality test of granger were used. The results indicate that GDP growth will increase the consumption of writing and printing papers but this relation is one-sided. On the other hand, there is no causality between changes in GDP and imports of printing and writing paper, and vice versa. Also, there is the one-side causality between GDP and consumption of newsprint. In the case of the Granger causality between economic growth and imports of newsprint, due to reject the null hypothesis, there was no relationship found, and vice versa.

In this study, some anatomical, chemical and physical properties of Meswak (toothbrush) wood (Salvadora persica) grown in Zabol region, Sistan and Baluchestan province were investigated. Anatomical studies showed that this species has short vessels (180.4 μm in length) with intermediate diameter, simple perforation plate and alternative intervessel pits. Ray parenchyma is homogeneous and of the procumbent cell type. Axial parenchyma is storied as seen in the tangential section and resembles paratracheal confluent arrangement in the cross section. Included phloem was present in xylem. The average fiber length, diameter, lumen diameter and fiber wall thickness were measured as 1898.5, 19.4, 8.2 and 5.6 μm respectively. Chemical characteristics showed that toothbrush wood average cellulose, lignin, extractives and ash content amounts to about 33.5, 21.5, 6.8 and 7.5%, respectively. The results showed that the density of the wood is 0.49 gram/cm3 and the mean tangential, radial and longitudinal shrinkages of this wood are 7.4, 7.8 and 0.98 %, respectively.

In this study, the effect of Pistachio shell flour and nanoclay loading on the physical and mechanical properties of wood plastic composite were investigated. The pistachio Shell flour was used in levels of 30, 40 and 50% and Nano clay (cloisite 15A) in three levels (0, 3 and 5%) was mixed with corn starch. Samples were made in a laboratory twin-screw extruder and then injection molding. The heating temperature profile and rotational speed of the screws were set at 180–170–160–160 oC and 60 rpm, respectively. Mechanical properties including tensile and flexural properties as well as notched impact strength and physical properties including water absorption and thickness swelling were measured. The results showed that flexural and tensile strength, water absorption of the samples increased as the flour content increased from 30 to 50% (w/w), but tensile modulus, notched impact resistance and thickness swelling decreased. Furthermore, tensile modulus increased as the Nannoclay content increased from 0 to 5% (w/w). Flexural and tensile strength, flexural modulus, notched impact resistance increased as Nannoclay content increased from 0 to 3% (w/w)and at higher dosage (to 5% (w/w), these properties were decreased. Water absorption and thickness swelling of the samples decreased as the Nannoclay content increased from 0 to 5% (w/w).

Due to the nature of wood and paper industries and the risks and incidents in such locations, the importance of safety and safety culture is essential for working in these industries. The aim of present study was to investigate the knowledge and attitudes of employees regarding safety culture. In this descriptive study, 236 workers were examined and the data confirmed the reliability and validity of the questionnaire. The data was statistically analyzed using appropriate statistical tests and SPSS software. In a total of 236 persons, 64% were high school graduated and less than, 8% were technicians and 18% were BA and MA. Mean and variance of age and experience, were 19.55 (7.02), 43.65 (7.40) years respectively. The results showed that eight factors have the most important role in contributing of the safety culture. After the factors rotation on each other, the variance accounted for over 45% of the variance that the first three factors; management commitment, the level of information exchange, observing to the rules and instructions are 11.41, 9.6 and 5.05 respectively. Eight factors are influential on improving the safety function and proper development of safety function in the studied companies. Managers with appropriate training programs, work safety and safety of staff will play an important role in the culture and knowledge of safety.

In this study, rice straw as an abundant and inexpensive raw material was selected to produce soda - anthraquinone pulp. Nano cellulose fiber from rice straw, cationic starch and cationic ployacrylamide were added to improve the pulp strength. Cationized nano cellulose fibers suspension was mixed with rice straw pulp at three levels (2, 5 and 10 percent) and mixed for five minutes. Starch and polyacrylamide as cationic chemicals were used to stabilize nano fiber cellulose at 1.5% and 0.2% (based on oven dried pulp) respectively. The result showed that there is a linear change between stock drainage time and paper strengths containing nano cellulose fiber. Tensile and burst strength indices were improved at 18.66% and 18.12% respectively by adding 10% of nano cellulose fiber to suspension treated with cationic polyacrylamide. Furthermore, the two indices increased by 19.35% and 19.24% by adding the maximum amount of nano cellulose fiber (10%) to pulp suspension cationized with cationic starch, respectively. The overall results indicated that nano cellulose fiber had a positive significant effect on the refined and unrefined pulp strengths of rice straw.