Iranian Journal of Wood and Paper Science Research
Year:2008 | Volume:23 | Issue:2 (29)|Papers Count:9

This study investigated the effects of production variables on physical and strength properties of air-formed OCC fibers / polymer composites. A combination of 12 treatments of OCC fibers and coupling agents for air-forming were investigated. Physical and mechanical properties of the sample were analyzed using factorial experimental design with completely randomized and DMRT test is used to classified the averages. The results of this study showed that addition of 70% OCC fibers to the polymers in air forming resulted in composites with higher strengths and modulus of rupture and 55% OCC fibers increased internal bonding, tensile strength and modulus, and lowered thickness swelling. Thickness swelling after 2 h water-soak and mechanical properties were improved by addition 2 and 4% coupling agent.

In this paper, a novel enzymatic method was evaluated for isolation and purification of wood lignin. The chemical structure of enzymatic lignin (Cellulytic lignin) was compared with conventional Bjorkman method (Milled wood lignin). The chemical structure elucidation was performed with FTIR, quantative 13CNMR, basic elemental analysis and Gel Permeation Chromatography (GPC). The results showed that enzymatic lignin preparation has a better chemical structure than MWL. Comparing to conventional isolation methods, application of an enzyme sequence with reduced milling time could lead to a mild extraction with less structural degradation of lignin. Resulting lignin could be more representative for wood lignin than milled wood lignin.

Total and per capita consumption of fluting paper was calculated using data and information from production, import and export for last decades. Then based on the fact that consumption of paper and paper products is a function of both per capita consumption and population of any country, regression analysis was used to predict per capita consumption for the period of 1994-2003, total consumption for the period of 2006-2011 as well as the year 2021. Finally based on the calculated consumption of different papers and considering the present and future capacities for paper production, the shortage of paper was derived. Results showed that the fluting paper consumption for the year 2021, will reach 290000 tons which causes 200,000 tons of shortage per year. This shortage will require that almost 70% consumption need to be fulfilled by import.

For this study 10 logs of Paullowina urtunie from Shastkalateh forest of Gorgan in Iran were selected randomly. After that, 45 clear flat swan specimens prepared and dried to 5% moisture. Density of each log and thickness of specimens were measured. Three levels of compression percent (16%, 33% and 50%) and temperature (130oC, 145oC and 160oC) were the variables. The physical properties of specimens such as spring back, compression set and thickness swelling were calculated. Also, MOE, MOR and impact resistance of specimens were evaluated. In order to have accurate examination, microscopic images were taken. Results show that, with increasing in compression percent, the amounts of spring back and thickness swelling enhance. Densification with 16% compression, yields deformation in elastic region while 33% and 50% compression, causes more compression set. The more compression percent, the more mechanical strengths and the highest strength attained in 50% compression. The effect of temperature was insignificant mostly. Finally, the proper treatment for Paullownia densification was 130oC and 50% compression. Microscopic images asserted the above results and illustrated that, the enhancing of densification above 50% compression is possible.

Canola straw as a agricultural residues has been investigated for MDF production. The variables were the steaming time of 2, 5 & 8 minutes and the resin content of 9 and 11 present. Other factors being kept constant. Some of the physical and mechanical properties such as thickness swelling (TS), water absorption (WA) modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), were measured. In addition, canola straw fiber properties such as fiber length, diameter and cell wall thickness were determined. The results showed that the optimum condition for MDF production from canola straw is the treatment of 5 minutes steaming time and 11% resin content. All the tested mechanical and thickness swelling properties improved with the increase of steaming time level. Dimensional stability of the MDFs improved as resin content increased. WA and TS values of the produced boards were relatively high because no wax and no depithing were used during the board production. Moreover, the values of canola straw fiber length, diameter and cell wall thickness are 1215, 28, 7.43 micrometer respectively.

We studied the possibility of replacing imported long fiber pulp (ILFP) with kenaf bast fiber soda pulp (KBFSP) to improve the quality of paper made with bagasse soda pulp (BSP). To do so, we produced BSP with kappa number 13.5 similar to that prepared by Pars Paper Mill. We also produced KBFSP with kappa number 21.6 similar to the unbleached imported ILFP. The yield percent for BSP and KBFSP were respectively 48.9 and 55.6 %. The maximum pulping temperature was 165oC; alkaline was 20% based on sodium hydroxide and ratio of liquor to dry weight of the raw material was 8:1. All the three pulps were beaten up to a freeness degree of 400 ml, CSF. Amounts of 0, 10, 20 and 30 percent ILFP and KBFSP were mixed with 100, 90, 80 and 70 percent BSP to produce hand sheets. In all cases of KBFSP mixing with BSP, the thickness of the generated hand sheets were higher than those produced through mixing ILFP with BSP while the density was lower. The difference in burst strength and breaking length of a mixture of 30% KBFSP with 70% BSP in the hand sheets were non-significant as compared with those of ILFP and BSP. Tear strength and opacity of mixing 30% KBFSP with 70% BSP were significantly higher than those of the ILFP and BSP with the same mixing ratio. We suggest that KBFSP provides a suitable replacement for ILFP to improve physical and strength properties of paper made with BSP.

In order to survey of possibility of particle board production with «Acacia salicina » the effectiveness of three factor (treatment) included adhesive percentage (in two surface: %9 and %11) temperature degree (in two surface 165oc and 175oc) pressing time (in three surface: 5.6 and 7 minutes) on mechanical (MOR, MOE, IB) and physical (TS2, TS24) properties were experimented with E.N standard. Therefore 36 boards were prepared for mechanical and physical tests. Data were analyzed with appropriated statistical method. Results indicate %11 adhesive, 165oc temperature degrees and 6 minutes press time is best condition for production. However the results showed more than standard IB (1.24 Mpa) probably due to its wood chemistry. Therefore this species could be a suitable source to produce particle board.

In this research, the possibility of using lignocellulosic fibers with polypropylene was studied. Three weight percentages of bagasse flour namely 40, 55 and 70 percent were chosen. MAPP was used as coupling agent at two weight percentages namely 4 and 6 percent. Bending strength was measured applying Instron 6025. Fracture surface was stadied using SEM to evaluate the interface between plastic and fiber. The results showed that with increasing bagasse, stress and work at yield point of bending was decreased and modulus of bending was increased. Also, increasing coupling agent resulted in improving stress, modulus and work at yield point of bending. SEM results showed that with increasing coupling agent, interface between plastic and bagasse fibers was improved.

In this study beech wood steamed specimens were compressed longitudinally to bulk cell wall at three levels of 0, 10 and 15 percent relative to their original length, and some mechanical properties including MOE, MOR, E-value, tensile strength, and tensile strain were measured. The results have shown that MOE, MOR and E-value as well as strength of specimens decrease with increasing compression but their tensile strain and work at maximum load increase.