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Volume 20, Issue 5
Displaying 1-10 of 10 articles from this issue
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1966 Volume 20 Issue 5 Pages 67
Published: 1966
Released on J-STAGE: January 25, 2010
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[in Japanese]1966 Volume 20 Issue 5 Pages 231-235
Published: May 05, 1966
Released on J-STAGE: November 11, 2009
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[in Japanese]1966 Volume 20 Issue 5 Pages 236-244
Published: May 05, 1966
Released on J-STAGE: November 11, 2009
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[in Japanese]1966 Volume 20 Issue 5 Pages 245-251
Published: May 05, 1966
Released on J-STAGE: January 25, 2010
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[in Japanese]1966 Volume 20 Issue 5 Pages 252-256
Published: May 05, 1966
Released on J-STAGE: November 11, 2009
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Makoto Usuda, Shigeo Ikeda, Jaime R. Navarro, Junzo Nakano, Nobuhiko M ...1966 Volume 20 Issue 5 Pages 257-264
Published: May 05, 1966
Released on J-STAGE: May 07, 2010
JOURNAL FREE ACCESSThe individual fiber strength were studied on sulfite pulp and kraft pulp prepared separately from pine early- and late-woods by varing cooking time. Pulp yield varied from 67% to 42% according to cooking time. The permanganate number of pulps, lateral order distribution and DP of cellulose were determined, and their effects on the strength of pulp were discussed.
The fiber strength of sulfite pulp and kraft pulp decrease with decreasing yield (sulfite pulp : 32-14 g/fiber, kraft pulp : 34-21 g/fiber). Comparing the fiber strength of these two pulps at the same level of yield, kraft pulp gives a considerably high strength. Neither DP nor lateral order distribution of cellulose can account for the cause of the higher fiber strength of kraft pulp. Leopold (1961) reported that xylan in wood fiber is located between fibrils, and contributes to the fiber strength by binding the fibrils. The fiber strength of kraft pulp rich in xylan, therefore, is expected to drop by the alkali extraction mo-re remarkably than sulfite pulp. However, on extraction of hemicellulose, the fiber strength of sulfite pulp decreased similarly as kraft pulp. In general, the degree of decrease in fiber strength diminishes as lowering pulp yield.
Forgacs (1961) pointed out that the fiber would be broken at “node”, i.e. local defects in sulfite fiber. Microscopical observation, however, revealed that the node exists in kraft pulp as well as in sulfite pulp (ref. to photo 3), and in many cases fiber was broken at this position on tensile test. Therefore, individual fiber strength shows the strength of locally damaged portion of wood fiber. In order to clarify the difference of fiber strength between sulfite pulp and kraft pulp, it is necessary to know the physical properties of the damaged portion.
The decrease in fiber strength on alkali extraction seems to be attributed to the expansion of this defect by the concentration of stress resulted from strong swelling. This assumption was ascertained by the results obtained from the determination of fiber strength of nitrated pulps.View full abstractDownload PDF (6451K) -
Minoru Sugaizumi, Katsumi Takeya, Yutaka Yoneda1966 Volume 20 Issue 5 Pages 265-273
Published: May 05, 1966
Released on J-STAGE: November 11, 2009
JOURNAL FREE ACCESSOn Stora process, Na2SO3 and NaHSO3 are used for the first stage as cooking chemicals.
The cost of the chemicals is relatively higher than that of ordinary Ca-SP process. Therefore re-used system and recovery system must be adopted in this process.
In the equilibrium state, the ratio of Na2SO3 to NaHSO3 in the solution used is determined by total SO2 and pH. However, the total SO2 value in the waste liquor is affected by the other reducing substances, therefore, usual iodometric titration cannot be employed in this case.
To the analysis of the total SO2 in Stora waste liquor, the method for Na2S, Na2SO3 and Na2S2O3 in KP black liquor was tried to apply. For this purpose, the basis of TAPPI standard T625m-48 have been investigated.
From the above investigation, the following new method was employed for the analysis of Na2SO3 and NaHSO3 in Stora waste liquor.
At the first, the value of total reducing substances (A) was determined by potentiometric titration using iodine without usual removal of organic precipitate formed by addition of ZnCO3.
Meanwhile, for the determination of reducing substances except Na2SO3 and NaHSO3, excess amount of formalin was added to the waste liquor for making the adduct of Na2SO3 and NaHSO3. After the treatment with formalin, the value of reducing substances (B) was determined potentiometrically using iodine.
From the difference between A and B, the true amount of total SO2 was determined easily.
Furthermore, it has been certified that the end point of the usual iodometric titration identified with potentiometrical method.
According to the result of actual routine work, it is concluded that new iodometric method is more useful and accurate on the determination of effective chemicals in waste liquor.View full abstractDownload PDF (1588K) -
[in Japanese]1966 Volume 20 Issue 5 Pages 275-282,290
Published: May 05, 1966
Released on J-STAGE: November 11, 2009
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[in Japanese], [in Japanese]1966 Volume 20 Issue 5 Pages 283-285
Published: May 05, 1966
Released on J-STAGE: November 11, 2009
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A. Harsveldt1966 Volume 20 Issue 5 Pages 286-290
Published: May 05, 1966
Released on J-STAGE: November 11, 2009
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