Structural change of Polyethylene single crystal mats by hot pressing was investigated by means of x-ray diffraction and differential scanning calorimetry. X-ray data showed that the deformation of the mat proceeded through the following stages. For a specimen pressed with lower compression ratios (C. R.) 1-5.3, the intra-lamellar<001> slip or the chain tilting developed resulting in a decrease of the lamellar thickness. With higher C. R. 5.3-11.7, locally concentated slips occurred in the mat and blocks of lamellar fragments rotated so as to decrease the angle between the chain axis and the direction of the deformation. In melting experiments, (1) a remarkable increase of the melting points occurred at higher compression stages (C. R.>5.3), (2) both of minimum half width of melting peak and minimum heat of fusion appeared at intermediate stages (C. R.=3.0_??_5.3), and (3) superheating effects became obvious at higher compression stages (C. R.>5.3). These results suggested that the structural and melting behaviors of compressed mats differed from that of drawn mats. The discussion was made on the assumption that a small number of tiechains in compressed mats mainly existed in the lamellar slip bands.
Relationship between spinning conditions and spinnability of polynosic fibers in the wet spinning was investigated using a single hole spinning apparatus. Maximum Jet Stretch (ν2c/ν1) and Maximum True Jet Stretch (ν2c/ν0c) were used for the criteria of spinnability, where ν2c: maximum take up velocity of the filament without break, ν1: average linear velocity of viscose filament in a spinnerette hole, ν0c: velocity of viscose filament at maximum diameter (d0) near the spinnerette surface at ν2c. In the case of the concentration of H2SO4 in the coagulating bath was sufficiently low, d0 was generally larger than the diameter of the spinnerette hole at any stretch. Therefore, True Jet Stretch was higher than apparent Jet Stretch. The relationship between H2SO4 concentration in the coagulating bath and ν2c/ν1 showed a curve having a maximum at lower H2SO4 concentration and a minimum at higher H2SO4 concentration (Maximum Jet Stretch Curve). The Maximum True Jet Stretch Curve also showed a maximum and a minimum at lower and higher H2SO4 concentrations respectively, and the acid concentration at the maximum substantially coincided with that of the Maximum Jet Stretch Curve, whereas, at the minimum it shifted slightly to a higher acid concentration compared with that of the Maximum Jet Stretch Curve. The H2SO4 concentrations where these two Jet Stretch Curves showed the maximum and minimum, varied depending on salt concentration, temperature of the coagulating bath, viscose feed rate, γ-value of viscose and spinnerette hole diameter. The maximum diameter of the viscose filament just behind the spinnerette surface at Maximum Jet Stretch decreased as H2SO4 concentration in the coagulating bath increased, and became equivalent to the diameter of the spinnerette hole at the H2SO4 concentration where the Maximum True Stretch Curve showed the minimum. Therefore, it was considered that the stress of taking up the filaments just began to be transmitted to the spinnerette surface at this H2SO4 concentration. The mechanism of the appearance of the minimum on Maximum True Jet Stretch Curves at the Maximum Jet Stretch Curves was discussed from a point of transmission of the stress for taking up the filaments.
In order to investigate stretching and deswelling behaviors of viscose filaments in a coagulating bath during the wet spinning of polynosic fibers, a new method of measurement of velocity distribution of filaments in the coagulating bath was studied. A single hole spinning apparatus was used, and the spinnerette was designed so that fine mercury particles were put into viscose at a constant rate at the stage of extrusion. The filament including mercury particles was photographed, and the velocity distribution was determined by measuring the distance of the mercury particles. Volume of the filament was calculated using the filament velocity and diameter. Using this method, influences of sulfuric acid concentration in salt free coagulating baths and Jet Stretch on the diameter, volume and velocity of the filament were studied. For the bath with H2SO4 concentration of 10g/l, the volume of the filament increased markedly compared with that of original viscose during the run of 200mm from the spinnerette surface in the coagulating bath. This phenomenon may indicate the osmosis of the coagulating bath into the filament. For the bath with H2SO4 concentration of 20g/l, the same phenomenon was observed in lesser extent. The velocity of the filament decreased just after passing the spinnerette surface from that in the spinnerette hole, and then recovered to a maximum velocity depending more or less on H2SO4 concentration in the coagulating bath. After reaching the maximum, the velocity of the filament decreased slowly to the take up speed by a longitudinal contraction of the filament. When Jet stretch was raised to 3.0, the velocity of the filament reached to maximum values at the distance of ca. 200mm from the spinnerette surface for the bath with H2SO4 concentration in 10g/l, and 20mm for the H2SO4 concentration in 30g/l. The stretching of the viscose filaments takes place in the paths 200mm or 20mm from the spinnerette surface depending on H2SO4 concentration. These results show that the present method is applied on the spinning under a very slow coagulation rate.
Sorption behavior of Hg2+ by the kerateine gel of thiol-type, which was prepared from wool keratin, was investigated. The behavior was discussed in relation to (i) the amphoteric nature, (ii) the chemical modification of side-chain polar groups, and (iii) the heat denaturation of kerateine gels. It was found that the apparent isoelectric point of the kerateine gel was closely related to the pH at which the Hg2+ uptake showed the minimum. The Hg2+ uptakes by modified kerateine gels in acid media depended on their modification history. The results indicated that in acid media, the dominant binding modes of Hg2+ consist in chemosorption by the thiol as well as amino groups in the kerateine gel and in chelation of Hg2+ through these groups. On the other hand, in neutral and alkaline media, very high Hg2+ uptakes were observed for all types of kerateine gels independent of their modification history. Such high Hg2+ uptakes could be explained in terms of the cooperative interactions between electron negative atoms incorporated in the kerateine gel, namely, sulphur, nitrogen, and oxygen rather than the ionization effect of the acidic groups present. The swelling volume of the heat-denatured kerateine gels decreased considerably with increasing the treatment temperature, and a good relation was found between the rate of Hg2+ uptake and swelling volume of the gel: the rate of Hg2+ uptake decreased with decrease in the swelling volume.
The amorphous contents in poly (ethylene terephthalate) (PET) films pre-treated with 18 kinds of solvents at 106-135°C for 3hours were determined by means of an infrared spectrophotometer. Approximately linear relationships were found between the amorphous contents in PET films and the shrinkage of PET filament yarns, or birefringences of PET films, respectively. Partition coefficients, diffusion coefficients and saturation values of Disperse Red 15 for the above pre-treated PET films were measured in iso-octane dye baths at 85-105°C, and correlated with the amorphous contents in the above PET films. These values increased approximately linearly with the amorphous contents. In particular, pre-treatment with solvents of which solubility parameter were around 10 or 12 gave higher values of partition coefficients, diffusion coefficients and saturation values. Heats of dyeing increased approximately linearly with the amorphous contents. However, activation energies for diffusion of dyes and energies required to make a path which dyes molecules moved through, decreased linearly with the amorphous contents. Dyeing properties of Disperse Red 15 on the PET films were dependent on the pre-treatment temperature even for the same amorphous contents of the films. The present results show that amorphous regions of PET having the same amorphous contents may be structurally different in certain cases.
A study was made to develop a size controller of raw silk by means of the analogue information processing technique coupled with a controlling mechanism. The size controller consists of the following four functional units; a filter, a comparator, a logic and an output units. Basic process technique for the size control is following. Namely, the size signal detected during the reeling is arranged by the filter. and the arranged signal is defined as the symbol V(t). V(t) is comparated with the set comparative voltage (V2) for level of limit size for cocoon feeding, the voltage (V1) for upper control limit size and the voltage (V3) for lower control limit size. In case of V1_??_V(t) or V3_??_V(t), the stop instruction is given from the controller to the reel stopper. In case of V2≥V(t), the instruction of cocoon feeding is given until V(t) rises higher than V2. In case of V1>V(t)>V2, no instruction is given. Mechanisms of cocoon feeding and reel stopper belonging to the reeling machine are operated on the instruction from the controller. In real operation, the size of raw silk reeled by means of the proposed technique is so close to the target size that the variance and the standard deviation of size are very small. It is confirmed that this control system based on the analogue information processing technique functions for the size control of raw silk during the reeling process.
The chaffs and straws, which are by-products of rice, and their acetylated products were filled into polyethylene. The thermal distortion and the mechanical properties of the composite were determined, and the effects of chaff and straw geometries and its applicability were discussed. 1) The heat distortion temperature and Young's modulus increased, and the tensile and impact strength and the elongation at break decreased with increasing the content of chaffs or straws. 2) The heat distortion temperature of the composite with the straws was higher than that with the flake-like chaffs. The tensile and impact properties were improved by increasing aspect ratio and the acetylated products were more effective than the non-acetylated ones. 3) The characteristics of the chaffs or straws suggest the good applicability as the filler in thermoplastics.