Iranian Journal of Wood and Paper Science Research
Year:2000 | Volume:- | Issue:10|Papers Count:3

In order to investigate the possibility of utilizing bagasse in high yield pulping, CMP and CTMP pulp from bagasse was compared.APMP pulping process was also investigated. Bagasse fiber length, diameter, lumen diameter and cell wallthickness was measured at 1166mm, 19.63 mLm,7.47 mLm, and 6.09 mLm respectively. Chemical composition was as follow: cellulose 553 %, lignin 20.5 %, ash 1.98% and extractive 2.9 %.The results and comparison of CMP and CTMP pulp are as follow: CTMP pulp yield was 3-4% higher than CMP pulp and the highest CTMP pulp at 80.7% was obtained at 15% NaOH application and 15 minutes chemical treatment time.Breaking length of both pulp was almost equal, but the burst index of CMP pulp was higher and the tear index was lower than CTMP. The highest breaking length of 3.85Kmwas obtained at 15% NaOH and 10 minutes, highest burst index of 4.81 KPa.m2/grat 20% NaOH and 20 minutes and highest tear index at 6.87 mN.m2/grat 15% NaOH and 15 minutes treatment time. Various treatments in APMP pulping reveald the following results: - Two stage pulping yield was almost 6% higher than one stage pulping and addition of H2O2 did not significant improve the yield.- The highest breaking length was related and two stage pulping. But addition of H2O2 in last stage and the lowest breaking length was related and two stage pulping with split application both NaOH and H202.- Even though two stage pulping with the addition of H2O2 in one stage produced highest burst index, but lowest burst index was with the CMP pulps.- Addition of DTPA produced highest brightness and opacity.

Eight-nineteen-year-old trees from Eucalyptus camaldulensis from De- hnow experimental Plantation located 160 Km. South west of Shiraz were selected randomly and fell two from each of the four blocks. Form each tree, 10 cm. thick cross-sectional discs at several different heights (3 meters intervals) were cut and together with remaining boles then transferred to the Alborz Research Center-Karaj for laboratory studies. The laboratory studies included determination of physical, anatomical and mechanical properties as well as chemical compositions of wood.The mechanical properties were evaluated on the ASTM methods for air-dry and green conditions. The following conclusions were drawn from this study:E. camaldulensis from one site in southern region of Iran has an average specific gravity of 0.806, Fiber length of 1.043 mm, fiber diameter of 15.38 mm, lumen diameter of 4.84 mm, cell wall thickness 5.29 mm, cellulose content of 42.5 percent. It was found that the mean values of modulus of rupture, modulus of elasticity and compression strength-parallel to grain tested at green condition were 81.19 MPa, 10887 MPa and 67.39 MPa respectively.Data are also presented on other mechanical properties such as impact strength, nail withdrawal cleavage and etc.