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Volume 40, Issue 12
Displaying 1-9 of 9 articles from this issue
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Toshitaka Kanai, Masami Tomikawa, JAMES L. WHITE, Jiro Shimizu1984 Volume 40 Issue 12 Pages T465-T479
Published: December 10, 1984
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe theoretical analysis of the tubular film extrusion by using a computer simulation presented several interesting results, such as bubble shape, velocity profile, temperature profile, deformation rate and maximum stretching stress.
The effect of bubble shape was found to be unchanged by variations in the viscosity level. The take-up tension and bubble inflation pressure increased in a linear manner with the viscosity magnitude. The magnitude of activation energy E (16.1 kcal/mol for LDPE, 11.1 kcal/mol for L-LDPE and 7.4 kcal/mol for HDPE) governed the bubble shapes and velocity profiles. A gradual increase in bubble diameter was predicted for LDPE and a wine stem shape for HDPE. The L-LDPE was intermediate. These theoretical results agreed with the experimental ones. We also obtained reasonable results of molten behavior for different process conditions when we considered the crystallization effect. From the theoretical analysis, raising the draw down ratio increased the stretching stress and the maximum deformation rate of both MD and TD. These effects were more remarkable on MD than on TD. Raising the blow up ratio increased the stretching effects of both MD and TD, and these effects were stronger on TD than on MD. Deformation rate decreased with increasing the frost line height, which decreased both MD and TD. Changing the frost line height influenced the cooling condition which was predicted by the heat transfer coefficient.
It can be said that the molten behavior predicted theoretically during the tubular film process agreed with that observed experimentally.View full abstractDownload PDF (969K) -
Takuma Jinda, Toshikazu Matsuda, Masanori Sakamoto1984 Volume 40 Issue 12 Pages T480-T487
Published: December 10, 1984
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSPoly (amic-acids) were synthesized from pyromellitic dianhydride (PMDA) and aromatic diamines, of which the resultant C-N bonds are coaxial and oppositely directed (rigid diamines), using Nmethylpyrrolidone as polymerization solvent. Random copolymers composed of rigid diamine, PMDA and 3, 3′, 4, 4′-diphenylethertetracarboxylic dianhydride (DTDA) were also synthesized. These poly (amic-acids) were partially imidized by adding an appropriate amount of acetic anhydride (15_??_30 mole% based on amic-acid unit) into their solutions and then wet-spun, since it was found that partially imidized polymer solutions gave more transparent and void-free coagulated fibers than poly (amic-acid) solutions as polymerized. These fibers were then chemically converted to polyimides by immersing them in an acetic anhydride-pyridine mixture and heat-drawn.
Relatively lower crystalline polyimides such as polypyromellitimides of aromatic diamines bearing chlorine substituent on the nuclei or random copolyimides had better drawability and gave fibers having higher tensile strength than higher crystalline polymers. For example, poly [2, 2′-dichloro-4, 4′-biphenylene/p-phenylene (70/30) pyromellitimide] gave a fiber having tenacity (T) 16.3g/d, elongation (E) 2.0% and initial modulus (Mi) 960g/d. Another random copolymer composed of benzidine/PMDA/DTDA (100/40/60) yielded a fiber with the following tensile properties: T 19.7g/d, E 1.7% and Mi 1310g/d.View full abstractDownload PDF (1040K) -
Hiroshi Yasuda, Hiroshige Sugiyama, Seisyu Hayashi1984 Volume 40 Issue 12 Pages T488-T493
Published: December 10, 1984
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSPreviously established theory on the steady-state multi-filament spinning was applied to the actual melt-spinning process of poly (ethylene terephthalate) using a simulation system. The birefringence of spun filament was corelated with the calculated value, δ95, which was obtained at the point where the ratio of yarn velocity to the take-up speed was 0.95. In order to increase the stability of spinning, the effect of variation of the stress calculated just below the orifice, and diameter of nozzle was examined. The eveness of denier in the fiber direction was found to be evaluated by the (dV/dx)max and Xm, which could be obtained at the maximum point of the summarized curve of (dV/dx), where V was the spinning velocity and x was the distance from the nozzle. The obtained results suggest that the theory was effectively applicable to the real melt spinning of multi-filament.View full abstractDownload PDF (311K) -
Koichiro Toriumi, Kazushi Fujimoto, Noriki Hamano, Atsuo Konda1984 Volume 40 Issue 12 Pages T494-T503
Published: December 10, 1984
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSTransients in melt spinning was analyzed by means of linearized perturbation equations, a valid analysis tool for small thickness variations in melt-spun filaments.
Transfer function between each disturbance input and resultant filament unevenness was derived through invariant analysis on linearized perturbation equation. Theoretical transfer functions thus obtained were compared with experimental results for two different input disturbances: cooling air temperature and cooling air velocity.
Results obtained are as follows;
(1) Transfer functions computed and expressed in Bode diagram form show that variations in cooling air velocity and cooling air temperature are comparable to variations in extrusion rate and take up speed with respect to their effects on short term filament unevenness.
(2) From result of melt spinning experiment it was found that, immediately below the spinneret, both cooling-air temperature and velocity were found to fluctuate considerably. Cooling air near the leeward filament was found to be considerably affected by the windward filament: air tempera-ture variation around the leeward filament was several times greater than the velocity variation and the leeward filament was more uneven than the windward filament.
(3) Sensitivity of filament thickness variation to disturbances in cooling air velocity and cooling air temperature depends on the position where the disturbances are exerted. Under the present spinning conditions the spinline was most sensitive to cooling air disturbance approximately 7cm below the spinneret. In conclusion, variation in cooling air temperature was found to be an important cause of filament irregularity.View full abstractDownload PDF (732K) -
Akira Isogai, Atsushi Ishizu, Junzo Nakano1984 Volume 40 Issue 12 Pages T504-T511
Published: December 10, 1984
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe distribution of substituents in partially substituted cellulose ethers (methyl-, carboxymethyl-, benzyl- and methallylcelluloses) prepared in aqueous and non-aqueous systems was studied. The reactivity order of three hydroxyl groups in cellulose in aqueous systems was HO-2>HO-6>HO-3 with the exception for benzylation. On the other hand, the reactivity order was HO-6>HO-2_??_HO-3 for etherifications with powdered sodium hydroxide and etherifying reagents except iodides in a non-aqueous cellulose solvent, SO2-diethylamine-dimethylsulfoxide system. The difference in reactivities of the hydroxyl groups in the non-aqueous system were much smaller than those in aqueous systems.View full abstractDownload PDF (502K) -
Hiroaki Sasaki, Hanpei Kido, Noriko Choji, Mikio Karasawa1984 Volume 40 Issue 12 Pages T512-T518
Published: December 10, 1984
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSIn order to study the dyeing behavior of textile assemblies, the diffusion coefficients of dyes in cotton cloth roll, namely a piece of cotton cloth wrapping around a glass tube and in aqueous solution were determined.
Two acid dyes were used and the dye bath was not stirred.
The results obtained are as follows:
(a) The concentration distribution in cotton cloth roll was in good agreement with Fick's law curve.
(b) The activation energies of diffusion were about 5 kcal/mol both in cotton cloth roll and in water.
(c) Each diffusion coefficient in cotton cloth roll and in aqueous solution decreased with an increase in NaCl concentration in the dye bath.
Then, the observed diffusion coefficients could be explained reasonably by assuming the pore model which has been accepted for diffusion of ionic dyes into cellulosic substrate: the calculated values agreed well with the experimental values.View full abstractDownload PDF (500K) -
MASARU KURIHARA1984 Volume 40 Issue 12 Pages P671-P678
Published: December 10, 1984
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSDownload PDF (2092K) -
KENZO NISHIDA1984 Volume 40 Issue 12 Pages P679-P683
Published: December 10, 1984
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSDownload PDF (1401K) -
MAKOTO USUDA1984 Volume 40 Issue 12 Pages P684-P688
Published: December 10, 1984
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSDownload PDF (471K)
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