Iranian Journal of Wood and Paper Science Research
Year:2002 | Volume:- | Issue:16|Papers Count:4

Three 4,6 and 12 years old populus deltoides trees were randomly selected and felled from the Safrabasteh Research Station located in Gilan province. Samples were transferred to the Wood chemistry and Paper Making of Research Institute of Forest and Rangelands. By using of kraft processing, percentage of sulfidity rate of %25, and the temperature of 165°C a addition to modification of effective alkali, up to 14%, 17%, 20% and cooking time at maximum temperature of 60 min., 120 min., 180 min., with a rate of liquide to lignocellulosics malerial equivalent at 5/1 (L/W).Average of yield and kappa number of pulps was measured between 43.83-2.20 and 14.85-30.48 respectively.Pulps were refined up to the freness degree of 350, 400 and 450 c.s.f for 14% effective alkali and 350 c.s.f. for 20% effective alkali. The mechanical properties of 60 grams hand-made papers include breaking length, burst Index, tear Index and folding were also measured.

In this study, MDF was produced from wet depicting Bagasse in three steaming time of 5, 10 and 15 minutes and in two steaming temperatures of 170°C and 180°C. There were 6 treatment conditions by combination of the above factors and three replications for each combination which resulted in producing 18 boards.The anatomical and chemical properties of Bagasse and also the physical and mechanical properties of MDF such as MOR, MOE, IB and swelling thickness after 2 and 24 hours were studied.Fiber length, fiber diameter, lumen cell diameter, and cell wall thickness were respectively measured 1.24 mm 22.90m., 12.48 m and 5.28m cellulose, lignin, extractives, and ash contents were 53.68%, 20.44%, 0.96% and 1.14% respectively.The measurement of MOR, MOE, IB and SW (after 2 and 24 hours) of the MDF revealed that the proper condition is obtained at the steaming temperature of 170°C and the steaming time of 5 minutes. The properties in the above-mentioned conditions were measured 12.22Mpa, 1370 Mpa, 0.13 Mpa, 47.11% and 52.22% respectively.

Wooden structure, specially vessels and launch boats were studied along all shores and ports of Persian Gulf, Oman Sea and Caspian Sea during two years in different seasons .Factors causing damage in the vessels and coastal wooden constructions were evaluated. Based on the results, north coasts, as compared to south cost of the country, were affected more intensively by fungi damages were lower at Caspian sea shores than those at shores of Persian Gulf and Oman sea. A major reason of this is lower level of salt in Caspian sea than in Persian Gulf. At the south coast, in addition to wood decay, marine borers are the main cause of damages. At coastal zones of Khozestan province, fewer damages were found, as compared to other points of several rivers flowing to the sea at these shores and sailing of vessels through low salt waters.

In this study, annual growth, bark content, fiher dimensions of pine wood (P. eldarica) were measured. Annual ring thickness and bark content 4.95 mm, 12.15% are determined respectively. Fiber length, fiber diameter, lumen cell diameter, cell wall thickness were determined 2.26 mm, 39.63m 29.06 m and 5.28 m respectively. Also felting coefficient 58.59, tear coefficient 36.24% and flexibility coefficient 18.12%were measured. Trend of variations of fibers dimensions indicated that fibers longth increased with increasing tree height from butt to crown. Also this property increased from pith to tenth annuad ring then decreased toward of bark. Cell wall thickness decreased from butt to 2 m. height and then increased. Also cell wall thickness decreased from pith toward bark.