A novel method has been developed for making the on-line measurement of the diameter profile of neck-like deformation in high-speed melt spinning process. This method utilizes the fluctuation of the position of neck-like deformation in spinline, and can measure the diameter change at a minimum interval of 2mm in the axial direction. Melt spinning of poly (butylene terephthalate) was carried out at take-up velocities of 3.5-5.0km/min, by using a spinning temperature of 255°C and a mass out flow rate of 5.5g/min. The moving velocity of the position of neck-like deformation was estimated as 1-2% of spinning velocity. In contrast to the fact that a diameter profile of conventional melt spinnig is asymptotic to final diameter, the diameter profiles obtained in this study showed an upward curvature at a position more than 50mm distant from the end point of neck-like deformation. Velocity gradient just before the solidification point increased with increasing the take-up velocity. The value of velocity gradient averaged over 2mm in axial direction reached ca. 20ms^-1 at a take-up velocity of 5.0km/min.

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Small-angle neutron scattering (SANS) from a particular specimen of high-speed spun poly (ethylene terephthalate) (PET) filaments at a spinning rate of 9000m/min was investigated under three different conditions; i.e., dried in vacuum, or moistened with D₂O or H₂O at saturated vapor pressure at 30°C. The results of the SANS experiments strongly suggested that there must be specific regions where the sorbed moisture is condensed to form clusters. The average one-dimensional component of radius of gyration of the clusters in the direction parallel to the fiber axis, R_g.m, was found to be 150-160 Å. The size of the clusters in the direction perpendicular to the fiber axis, R_g.e, seems to be considerably larger than R_g.m, and is beyond the resolution of the SANS instrument used in this study for any possible measurement. The results did not necessarily deny the existence of the moisture sorbed in the amorphous region of PET with less interaction than in the liquid state, as suggested from a good linear relationship between the degree of non-crystallinity and the moisture up-take obeying the Henry's solution law for a series of high-speed spun filaments. The SANS from such a phase of moisture dissolved uniformly in the amorphous region is, however, too weak in its contrast to be in consistence with the detected scattering intensities. Thus, the picture of moisture sorption in the particular specimen may be drawn as follows: with increase in the vapor pressure, at first the moisture is uniformly dissolved in the amorphous region of PET to a certain extent (solution component), and then the moisture is condensed in localized regions such as voids to form the water clusters (condensation component).

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Morphology and crystal orientation of poly (tetraoxane) (PT_EOX) prepared by γ-ray induced polymeriza tion of tetraoxane (T_EOX) single crystal were studied. The two-step postpolymerization process was applied and the polymer yield was high. The polymer yield is rather low at the first step postpolymerization, but it significantly increased at the second step because of the presence of PT_EOX formed at the first step. The role of the resulting polymer can be considered to act as spatial guide or a substrate for epitaxial growth when the polymer chain grows. The extended chain crystal is always formed by this polymerization method and the lamellar crystal is formed at postpolymerization temperature above 80°C, while the subcrystal is formed below 90°C. Though all samples show net-like texture, most of the molecular chains orients along the fiber axis, impling that these polymers are composed of the so-called “shish kebab” structure.

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The elastic behaviors of the drawn/annealed thin films for syndiotactic-rich poly (vinyl alcohol), derived from vinyl trifluoroacetate, were studied by the repeated elongation/contraction cycles in water. For the drawn films annealed at temperatures below 125°C, the characteristic of deformation was divided into two regions in all cases, that is, low-elongated and high-elongated regions. The elastic deformation was dominant over the plastic deformation in the low-elongated region and vice versa in the high-elongated region. For the drawn films annealed at temperatures above 150°C, the characteristic of deformation was given roughly the high plastic deformation accompanying with elastic deformation.

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Preparation of photoreactive LB films was carried out using polymers/oligomers, which were prepared by “four-center type photopolymerization” and have cyclobutane rings in the main chain. The polymers/oligomers having long-chain alkyl ester residues, formed stable monolayers on the water surface when mixed with arachidic acid. These monolayers could be deposited onto a substrate successfully forming Y-type films. The oligomer LB films were polymerized on irradiation. The polymer LB films showed photo-reversible process between polymers and oligomers, depending on wavelength of irradiating light. This photochemical behaviour was found to be caused by the cleavage and formation of cyclobutane rings.

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The effect of the predrying conditions on the physical properties and the crosslinking structure of cotton fabrics treated with dimethylolethyleneurea was studied. The physical properties and crosslinking structure of treated fabrics are obviously affected by the predrying conditions. At the same predrying temperature, a higher moisture content in the predried fabrics results in an obvious agent migration, promoting the hydrogen-bond protective effect, which improves the dry crease recovery angle (DCRA) of treated fabrics; therefore, the linear relation between the DCRA and the product of the root of the crosslinking length, the number of crosslinks and the degree of completion of the crosslinkage (r√nα) is affected. For the same 4-5% moisture content in the predried fabrics, a lower predrying temperature results in an obvious penetration of the crosslinking agent in lamella, promoting the swelling property of fiber, which improves the wet crease recovery angle (WCRA) of treated fabrics; therefore, the relation between the WCRA and the product of the crosslinking length, the number of crosslinks, and the degree of completion of the crosslinkage (rnα) is affected, and this phenomenon is more obviously observed in the presence of methanol in the padding solution.

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The wind force resistance of the clothed human body exposed to high-speed wind was studied according to the fluid mechanical test by using cylinders wrapped with a cloth. Relations between wind force resistance, C_D, and Reynolds number, Re, were expressed as C_D-Re curves, which were analyzed for various surface roughnesses, H. The H-dependences of C_D^*, the minimum value of C_D, and Re^*, the Reynolds number corresponding to C_D^*, for cylinders wrapped with a low air permeability cloth were nearly same as those for the naked cylinder, showing negative dependences of C_D^* on Re^*. It was found that wrapped cylinders show smaller resistance than unwrapped cylinders in certain conditions. It was concluded that a cloth can be selected that reduces wind force resistance.

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Blood compatibility of regenerated silk fibroin was ecamined by in vivo blood tests. In vivo tests were made by a method of peripheral vein indelling suture. The coating of sample fibroin on the polyester suture was made by casting either from aqueous or from formic acid solution. The fibroin-coated sutures from aqueous solution were treated with methanolic aqueous solution in order to denature the silk fibroin, and implanted into a jugular and femoral vein of a dog. The results of the test method employed in this work indicate that the regenerated silk fibroin is nonthrombogenic.

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