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Volume 26, Issue 4
Displaying 1-7 of 7 articles from this issue
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Andrzej Ziabicki1970 Volume 26 Issue 4 Pages 147-155
Published: April 10, 1970
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSTheoretical study on the problem of molecular orientation in polymer systems is carried out. The mathematical treatments are made on general case, including earlier theories. Every stage of molecular orientation in practical cases can be regarded as a special case from this point of view. Macroscopic characteristics of orientation are calculated in terms of parameters of every special case according to the theory. Discussions are developed to the problems of molecular orientation during fiber spinning, drawing and heat-setting processes.View full abstractDownload PDF (541K) -
Andrzej Ziabicki1970 Volume 26 Issue 4 Pages 156-162
Published: April 10, 1970
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe effects of phase and structural transitions during fiber formation are theoretically considered. From this point of view, practical fiber forming processes are classified into three cases, that is, one-, binary- and ternary- or multi- component systems, which correspond to melt-, dry- and wet-spinning respectively. Principal transitions during every system are pointed out and roles of them in each process are discussed. Especially, ternary system and gelation are somewhat minutely considered.View full abstractDownload PDF (406K) -
Yoshitaka Ogiwara, Kenichira Arai1970 Volume 26 Issue 4 Pages 163-167
Published: April 10, 1970
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe graft copolymerization of vinyl acetate onto cellulosic materials and the saponification of the copolymers were studied.
The maximum graft per cent of 300% was obtained under the following conditions; ceric salt concentration, 1.48m mole/l; vinyl acetate concentration, 2.0 mole/l; and reaction time, 3 hours.
From the kinetic studies, it was found that the polymerization rate is proportional to the onehalf power of vinyl acetate concentration and the polymerization degree of the branches is almost proportional to the three-fourth power of the monomer concentration. From these results, it is concluded that the efficiency of ceric salt-initiated graft copolymerization is very low under these conditions.
It was also found that the logarithmic plots of per cent grafting or polymerization degree of br anches vs. reaction time are expressed with two straight lines, respectively. The time corresponding to these inflection points approximately coincides with that after which the number of branches is unchanged. As for the slope of these lines, that of the shorter-time side was larger than that of longer time-side for per cent grafting, and that for polymerization degree shows an opposite tendency. Consequently, it is concluded that the first inclination of these lines represents the increase of the number of branches, but in the second stage “regrafting” to the branches occurs as a result of the chain transfer of homopolymer radicals whereas the number of branches is almost leveled.
The optimum consistency of the saponification liquor for this copolymer was found as fllows; sodium hydroxide, 0.1g; copolymer, 1.0g; methanol, 30ml; and water, 20ml.
In the saponification of these copolymers, the weight loss is much larger than that calculated theoretically, even when about 2% of acetyl aroup remains in the copolymer after saponification. This excess weight loss may be caused with the particilar polymer structure formed by the chain transfer of homopolymer radicals to the methyl group of grafed poly (vinyl acetate).View full abstractDownload PDF (349K) -
Harumichi Shimizu, Shinko Nishide, Yoshiharu Shinozaki, Gisuke Meshits ...1970 Volume 26 Issue 4 Pages 168-173
Published: April 10, 1970
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSSilicone-grafted cotton fabrics were prepared by using the simultaneous irradiation technique in air. The water repellency, the durability for dry-cleanings and abrasions of the grafted samples were tested and compared with the silicone-coated cotton fabrics prepared by heating in the presence of catalysts.
A spray test rating of 100 was obtained for the grafted samples with over 1% grafting and for the coated samples with over 3% add-on. The grafted samples with 1.5_??_5.5% grafting showed a contact angle of about 130° against water drops, while the coated samples with 5.0% add-on showed an angle of about 120°. The durability of water repellency was improved by increasing the irradiation dose. The spray test rating of the grafted samples prepared by the irradiation of about 4 Mrads was over 80 even after 10 times of dry-cleanings or 10 times of abrasion tests, but that of the coated samples containing the same amount of silicone was reduced to 50 after 3 times of these treatments. The durability of water repellency of the grafted samples was improved by the heat treatment at higher temperature and / or by ageing.
These results indicate that the irradiation grafting technique is much more superior to the usual coating technique for the water repellency and its durability. From the experimental results, it is suggested that the water repellency is influenced by the shape of silicone deposition on the fibers and that the durability of water repellency depends on the degree of bonding of silicone to the fibers.View full abstractDownload PDF (445K) -
Shin'nosuke Miyauchi, Munenori Sakamoto, Hiroaki Tonami1970 Volume 26 Issue 4 Pages 174-180
Published: April 10, 1970
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSTwo kinds of disulfide-crosslinked polycaprolactam (DSPC) fibers with different disulfide (SS) contents (M2 and M4) were prepared from N-mercaptomethylated polycaprolactams and the set of them in various aqueous media was investigated.
When M2 (sulfur content, 1.2%) was treated at 100% extension in cold water for 5 min, temporary set (measured after relaxation in the air) of 60% was obtained. The set did not increase significantly with prolonged setting treatment. When M2 was kept at 100% extension in cold water, the initial rapid decay of the stress followed by levelling-off was observed. It is considered that the mechanism of set of M2 in cold water is rearrangement of hydrogen-bonded network stabilizing the set structure. The temporarily set M2 supercontracted when relaxed in boiling water, since the hydrogen-bonded network formed during setting was broken in boiling water. M4 (sulfur content, 3.3%) was rubbery in water and could not be set by treatment with cold water.
When M4 was treated in boiling water for 60 min, temporary set of 50% was obtained. Permanent set of 22% was retained when the set fiber was relaxed in boiling water for 60 min. A smaller permanent set of 9% was obtained by the treatment of M2 in boiling water for 60 min. Both M2 and M4 contained a small amount of mercapto (SH) groups. M2 modified with 2, 4-dinitrofluoro-benzene, which blocks SH, could not be set with boiling water. The controlling mechanism of set and its release in boiling water appears to be rearrangement of crosslinked structure via SH/SS interchange reaction.
When M2 and M4 were treated in aqueous ammonium thioglycolate at 25°C, large amounts of temporary sets were obtained. The stress relaxation and X-ray diffraction studies revealed that SS crosslinks were ruptured in a short time and DSPC fibers underwent orientation and crystallization. The set was lost when the fibers were relaxed in boiling water.
When M4 was treated in 0.5% KCN at 50°C for 1hr, the highest amound of permanent set (67%) was obtained. It is considered that the set with KCN is due to the breakdown of SS crosslinks and subsequent formation of monosulfide crosslinks which are stable in boiling water.
M4 pretreated with KCN solution could not be set with boiling water. This is another supporting evidence for SH/SS interchange mechanism to the setting in boiling water.
The mechanism of set of wool keratin fibers was discussed in relation to the above results.View full abstractDownload PDF (1748K) -
Masamitsu Nagano, Mineo Uosumi1970 Volume 26 Issue 4 Pages 181-184
Published: April 10, 1970
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSIn order to make the conjugated fiber of PVA and nylon by interfacial polycondensation, a typical reaction employs a mixture solution of hexamethylene diamine and PVA, and a sebacyl chloride. The strength and Young's modulus of these fibers increase with the contents of PVA.
According to the IR spectroscopic research and X-ray diffraction pattern, it is supposed that the chemical bonds between the nylon and the PVA would be formed, and the nylon and the PVA may also be crystallized separately.View full abstractDownload PDF (634K) -
Masamitsu Nagano, Mineo Uosumi1970 Volume 26 Issue 4 Pages 185-188
Published: April 10, 1970
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSIn order to spin the aromatic nylon by the interfacial polycodensation, the experiments are carried out by the reaction between the hexamethylene diamine and isophthaloyl diacid chloride. The optimum spinning conditions for this case are as follows:
a) Molar ratio of the diamine to acid chloride=0.6
b) The interfacial area=48.7mm2
c) Temp. of reaction=55°C
d) The winding up speed=3.47m/min.
e) The concentration of NaOH=0.14mol/100 cc H2O
f) The concentration of surfactunt (SLS)=1.17×10-3mol/100 cc H2O.
The Young's modulus of this fiber is five times greater than the 6.10 nylon after the drawing of five hundred percents.View full abstractDownload PDF (215K)
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