Showing papers by "Shiro Saka published in 1993"
01 Jan 1993
TL;DR: In this article, the molecular arrangement and ultrastructure of wood cell walls are described in relation to the physical and mechanical properties of wood as a natural composite material, and the chemical composition of wood is also summarized to illustrate the heterogeneity in distribution of the cell wall constituents.
Abstract: The architecture of the molecular arrangement and ultrastructure of wood cell walls is described in relation to the physical and mechanical properties of wood as a natural composite material. The chemical composition of wood is also summarized to illustrate the heterogeneity in distribution of the cell wall constituents.
50 citations
Patent•
13 Sep 1993
TL;DR: In this article, a fatty acid ester of cellulose has been proposed, which has excellent transparency, filterability and spinnability in spite of its high content of mannose and xylose.
Abstract: A fatty acid ester of cellulose having excellent transparency, filterability and spinnability in spite of its high content of mannose and xylose, wherein the total molar content of mannose and xylose accounts for at least 7% of that of glucose, mannose and xylose, and the amount of filtration satisfies a specified requirement. Such a fatty acid ester of cellulose is prepared by using a pulp having a low α-cellulose content as a raw material and a fatty acid corresponding to the ester as a diluent and adding an organic solvent in an amount of at least 10% by weight based on the diluent in any step during the preparation. In the preparation of cellulose diacetate, which excellent filterability and transparency, by the acetic acid process, the cellulose diacetate obtained by aging is dissolved in a solvent which can dissolve it and the resulting cellulose diacetate is recovered.
16 citations
TL;DR: In this article, the second peak, prehump II, was fractionated by using the large-scale GPC column and its molecular properties were investigated, and it was shown that the molecules of pre-Hump II are not aggregated but molecularly dispersed with some anionic residues.
Abstract: Cellulose acetate in acetone solution is known to show some peaks in its chromatogram as measured by gel-permeation chromatography. These peaks are named from the shorter elution time as prehump I, prehump II, and main hump. In our previous paper, we characterized prehump I. In this study, the second peak, prehump II, was fractionated by using the large-scale GPC column and its molecular properties were investigated. The results have shown that the molecules of prehump II are not aggregated but molecularly dispersed with some anionic residues. These anionic groups may be sulfuric acid groups introduced during the acetylation process as a catalyst that interact repulsively with the anionic groups of the GPC column gel. This resulted in the phenomenon that the prehump II elutes earlier than the main hump in the GPC chromatogram. © 1993 John Wiley & Sons, Inc.
14 citations
Patent•
13 Sep 1993
TL;DR: In this paper, a fatty acid ester of cellulose is used to obtain a low alpha-cellulose content as a raw material and a diluent and an organic solvent in an amount of at least 10% by weight.
Abstract: of EP0590401A fatty acid ester of cellulose excellent in transparency, filterability and spinnability in spite of its high content of mannose and xylose, wherein the total molar content of mannose and xylose accounts for at least 7% of that of glucose, mannose and xylose, and the amount of filtration satisfies a specified requirement. Such a fatty acid ester of cellulose is prepared by using a pulp having a low alpha -cellulose content as a raw material and a fatty acid corresponding to the ester as a diluent and adding an organic solvent in an amount of at least 10% by weight based on the diluent in any step during the preparation. In the preparation of cellulose diacetate, which is excellent in filterability and transparency, by the acetic acid process, the cellulose diacetate obtained by aging is dissolved in a solvent which can dissolve it and the resulting cellulose diacetate is recovered.
5 citations