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Volume 52, Issue 4
Displaying 1-14 of 14 articles from this issue
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Hiroshi Toyoda, Hiroshi Sakabe, Takashi Itoh, Takashi Konishi1996 Volume 52 Issue 4 Pages 163-168
Published: April 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSStructures and mechanical properties of the ultra-quenched polytetrafluoroethylene cast film (UQ-PTFE), which was prepared by being rapidly immersed into the ethanol/methanol mixed gel (-160°C) cooled in liquid nitrogen after the sintering at 400°C for 60min, being compared with those of the slowly cooled PTFE cast film (SC-PTFE). The degree of crystallinity of UQ-PTFE was about 30%, which increased with decreasing the cooling rate to be 80% finally for the slowly cooled sample. The distinct morphological characteristics or the band structure was not observed in the UQ-PTFE, which was highly transparent. The breaking elongation of SC-PTFE decreased as temperature reduced from 50 to 0°C, while high tensile strength and high breaking elongation of UQ-PTFE were retained even at 0°C. The transitional phenomena in the crystalline region was also examined using thermomechanical analysis and dynamical viscoelasticy measurement, being associated with the molecular mobility.View full abstractDownload PDF (992K) -
Siripong Premjet, Yoshito Ohtani, Kazuhiko Sameshima1996 Volume 52 Issue 4 Pages 169-174
Published: April 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSFive different types of lignosulfonate samples and five effectors; i.e. Calcofluor, Congo red, carboxy methyl cellulose (CMC), caffeine, and theophylline were added into a medium for a culture of Acetobacter xylinum ATCC 10245 and their effects on cellulose membrane production were compared. All the five lignosulfonate samples remarkably increased the bacterial cellulose membrane yields more than those of the effectors. The highest yield (389% to the standard medium) was obtained when 0.7% of a sodium lignosulfonate sample were added. The sodium lignosulfonate showed the average molecular weight of 18, 000 and the sulfonyl group content of 0.90 meq/g. CMC, caffeine, and theophylline were also slightly effective on cellulose membrane yields but Calcofluor and Congo red gave the negative effects.
X-ray diffraction diagrams of the bacterial cellulose membranes showed different peak intensities in the diffractograms corresponding to (101) and (002) of crystallographic planes. Addition of any kinds of lignosulfonate samples increased not only the cellulose yields but also the crystallinities of cellulose membranes, especially the addition of sodium lignosulfonate showed the highest crystallinity value. Lignosulfonate is assumed to be the new type of stimulator for bacterial cellulose membrane production because they have potential for the increase in not only the cellulose membrane productivity but also the crystallinity of the cellulose membrane.View full abstractDownload PDF (414K) -
Yoshito Ohtani, Takuro Noguchi, Kazuhiko Sameshima1996 Volume 52 Issue 4 Pages 175-179
Published: April 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSKenaf bast was pulped by several alkaline cookings. Soda-anthraquinone pulping is superior to soda pulping and comparable to kraft pulping with respect to pulp yield and delignification ability. All of three commercial anthraquinone and its precursors were effective for kenaf bast pulping in a same level, but a little difference between kenaf bast and wood pulpings was found. Anthraquinone could enhance the delignification but could not contribute to any yield increase in the kraft pulping of kenaf bast. Kenaf bast fiber resembles the fibers from woody basts, like as kozo, mitsumata and so on. But the detailed characteristics should be further elucidated.View full abstractDownload PDF (742K) -
Masaki Nishiyama, Akira Isogai, Fumihiko Onabe1996 Volume 52 Issue 4 Pages 180-188
Published: April 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSAlkenyl succinic anhydride (ASA) is one of the reactive sizes used as cationic emulsions at wet-end of papermaking process. In order to make clear the mechanism of ASA sizing, structures of ASA components retained in handsheets were studied using model compounds and analytical techniques. The results of model experiments using low-molecular-weight cellulose and cationic starch showed that ASA was predominantly hydrolyzed to alkenyl succinic acid (ASAcid) in the presence of water without forming ester linkages with hydroxyl groups of carbohydrates. Sheet-form and fibrous-form extractions with organic solvents under various conditions indicated that most of ASA components were present as the structure of ASAcid in ASA-sized handsheets. The results of curing treatments of ASA-sized handsheets and impregnation treatments of ASA-related compounds into filter papers also were negative to the formation of ester linkages between ASA and cellulose-OH. Cellulase-treatments of ASA-sized handsheets followed by IR analysis of the obtained residues showed that ASA components were mostly present as the structure of ASAcid in papersheet. ASAcid aluminum salts may be present to some extent in papersheet prepared by ASA-alum systems. All these results imply that appearance of sizing features for ASA-sized papersheet is brought about by ASAcid molecules in papersheet. However, since non-reactive ASAcid has no sizing effect when added to pulp suspension, the reactive structure of ASA must be necessary for paper sizing because of some mechanisms other than the formation of ester linkages with hydroxyl groups of pulp fibers.View full abstractDownload PDF (651K) -
Masaki Nishiyama, Akira Isogai, Fumihiko Onabe1996 Volume 52 Issue 4 Pages 189-194
Published: April 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSAlkenyl succinic anhydride (ASA) gives sizing features efficiently to papersheet by being added to pulp suspensions as cationic ASA emulsions. Although the reactive structure of ASA is necessary for paper sizing, the previous paper revealed that alkenyl succinic acid (ASAcid), the hydrolyzed form of ASA, is the predominant component present in ASA-sized papersheet _??_1_??_. Then the roles of reactive ASA in paper sizing were studied in terms of hydrophobicity and coalescent and crystallizing behavior of ASA and ASAcid. The results obtained by sizing features of handsheets prepared with ASA-ASAcid-mixed emulsions, microscopic observations of the ASA-ASAcid-mixed emulsions, X-ray diffraction patterns of cellulase-treated residue of handsheets and apparent contact angles of water drops on ASA and ASAcid showed that ASAcid is hydrophobic and has coalescent, coagulating and crystallizing behavior in aqueous media, compared with ASA. These differences in properties between ASA and ASAcid may lead to the following hypothesis of mechanisms of efficient paper sizing with reactive ASA emulsions; (a) the reactive structure of ASA is necessary for achieving sufficiently distributed states of size components with smaller coagulating structures on hydrophilic pulp fibers in the papermaking process, (b) then more hydrophobic ASAcid molecules are formed without forming large coagulating structures probably during drying process of papermaking, maintaining the sufficiently distributed states, and (c) thus sizing features appear efficiently on ASA-sized papersheet by sufficiently distributed ASAcid molecules on pulp fibers.View full abstractDownload PDF (1524K) -
Akira Isogai, Masaki Nishiyama, Fumihiko Onabe1996 Volume 52 Issue 4 Pages 195-201
Published: April 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSThe mechanism of retention of alkenyl succinic anhydride (ASA), which is one of the neutral sizes for papersheet, on pulp fibers at wet-end of papermaking process was studied in terms of roles of carboxyl groups in pulp fibers and those of cationic polymers and aluminum sulfate (alum) added to pulp suspension. ASA content in handsheets were determined using pyrolysis-gas chromatography (PY-GC). The results obtained using carboxylgroup-blocked pulp showed that carboxyl groups present in pulp fibers had a role to form ionic linkages with cationic ASA emulsion particles, and thus the ASA retention was mostly governed by the carboxyl groups of pulp fibers. The additions of cationic polymer and alum to pulp suspension resulted in increases in ASA retention on handsheets, and consequently their sizing features were improved. Some ASA emulsion particles originally having cationic surface charges are turned to those having amphoteric surface charges by alkenyl succinic acid (ASAcid), which are formed from ASA by hydrolysis on the surfaces of the ASA emulsion particles. Therefore, further retention of ASA may have been brought about on papersheet by additional ionic linkages formed between anionic pulp fibers, amphoteric ASA emulsion particles, cationic polymers and cationic aluminum compounds.View full abstractDownload PDF (1010K) -
Yoshihiko Onogi, Kanako Uenishi, Chikako Matsuda, Mitsunobu Kitamura1996 Volume 52 Issue 4 Pages 202-205
Published: April 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSSolid density has been measured using various methods, among which the volume expansion method is rather simple in principle. It has been extensively used for solid powder samples, but only for few polymer samples. We tried to use this method to measure the density of various dried polymer samples using helium and nitrogen as measuring gases. The densities obtained were comparable with those found by other methods. Considering the effect of the measuring gas size, the polymer microstructure is discussed based on the observed density of textile fibers.
The density of humid samples was calculated to be much larger than that of dried samples. Though the effect of water molecules on the density value could not be clearly explained, it is surmised to be the reason for the volume expansion method not being used for density measurement of polymeric materials.View full abstractDownload PDF (274K) -
Machiko Shimada Takigami, Osamu Tamura, Shoji Takigami, Yoshio Nakamur ...1996 Volume 52 Issue 4 Pages 206-212
Published: April 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSCoupling reactions of lipase with polyacrylic acid or acrylic acid/acrylamide copolymers were carried out using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as a coupling reagent. The reaction temperature, pH, the molecular weight and concentration of polyacrylic acid had considerable effects on the coupling reactions. When the coupling reaction was carried out at 10°C and pH 7, the lipase content in the polymer-coupled lipase was slightly less and the relative activity of the coupled lipase was higher than those coupled at 20°C and pH 4. The lipase content in the polymer-coupled lipase decreased and the relative activity of the sample increased with the increase of molecular weight and decrease of polymer concentration. Acrylic acid/acrylamide copolymers with different composition were also used for the coupling reaction. The less acrylic acid component the copolymer had, the higher activity the coupled lipase showed. All results were explained in terms of the number of reaction sites defined as the number of polymer molecules per lipase molecule.View full abstractDownload PDF (416K) -
Hiroo Iino, Seiji Tokino, Jangmi Ryu, Meilan Chen, Masakazu Suzuka, To ...1996 Volume 52 Issue 4 Pages 213-219
Published: April 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSWool and nylon 6 fabrics were dyed with direct and acid dyes in yellow, red and blue, and then treated by sputter etching and silicone resin coating. The apparent color depth (K/S) value of both treated fabrics was increased, especially by sputter etching. Change in color was investigated by metric lightness (L*), metric chroma (C*), metric hue angle (h) and color difference (ΔE*) parameters on the basis of CIELAB color system. ΔE* was especially increased by sputter etching. In this case, the decrease of L* was small, whereas C* increased remarkably. Especially the increase of C* by sputter etching was brought about at high dye concentration. On the other hand, the increase of C* by silicone resin coating was not observed. As is evident from SEM observation, innumerable fine microcraters were produced on the fiber surface by sputter etching. These microcraters play an important role for the repression of light reflectance. For example, it is clear that the microcraters contributes to the increase of C* of the dyed wool and nylon 6 fabrics.View full abstractDownload PDF (983K) -
DAI HARA1996 Volume 52 Issue 4 Pages P161-P165
Published: April 10, 1996
Released on J-STAGE: June 30, 2008
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TATSUFUMI TOHARA1996 Volume 52 Issue 4 Pages P166-P170
Published: April 10, 1996
Released on J-STAGE: June 30, 2008
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MASAKI FUJITA1996 Volume 52 Issue 4 Pages P171-P176
Published: April 10, 1996
Released on J-STAGE: June 30, 2008
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MASAO HORIO1996 Volume 52 Issue 4 Pages P177-P180
Published: April 10, 1996
Released on J-STAGE: June 30, 2008
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MASATOSHI TAKEUCHI1996 Volume 52 Issue 4 Pages P181-P183
Published: April 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSDownload PDF (752K)
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