The osmosis through dense membrane of cellulose diacetate (CDA), cellulose triacetate (CTA) and of poly(γ-methyl L-glutamate) (PMLG) has been characterized concerning several membrane parameters, such as filtration coefficient, Lp, permeability coefficient of KCl, ω, and reflection coefficient, σ. Lp and ω of PMLG were higher than those of CTA whose equilibrium partition coefficient and degree of hydration were almost identical with those of PMLG. The differences in Lp and ω could be ascribed to the difference of diffusion mechanism of these membranes. On the other hand, reflection coefficient of these membranes, which is directly related to the membrane osmosis, was given by the following order: The values of Lp, ω, and σ in turn were related to the frictions, fwm (water-membrane), f2m (co•ion-membrane) and f2w (co•ion-water). The order of σ was determined by the fact that f2m of PMG-KCl system was considerably lower than those of cellulosic systems. This difference of f2m is attributable to the fact that α-helical PMLG has loosely packed side chain region through which the solute permeate the membrane easily, on the other hand, cellulosic membranes consisting of linear main chain have no such region.
A unique relationship was found between the melting peak temperature and the degree of methoxymethylation (substitution) for nylon-6 films, the substitution being made to different extents after annealing at 220°C (near the melting point of nylon-6). In the 1st-run of the DSC measurement, the melting peak temperature was almost constant against the degree of substitution. In the 2nd-run after cooling the same sample, however, the melting peak temperature was depressed with the increase of the degree of substitution, in accordance with the modified Flory's equation employing a=2 and the lower side peak temperature, as T°m, of double melting peaks. This result means that the methoxy-methylation of the nylon-6 chain randomly took place and subsequently the recrystallization by cooling after melting gave rise to formation of an appreciable amount of fringed-type crystals.
Fine structures of high speed spun PET filaments obtained at take-up velocity, 1000-9000m/min, were investigated by X-ray analysis. Crystalline density calculated from the measured unit cell parameters increased with increasing take-up velocity from 5000 to 700 m/min and then decreased slightly by further increase of take-up velocity. The crystalline density of 7000m/min filaments was calculated as 1.494g/cm3. Crystallite sizes and crystalline imperfection parameters were estimated from wide-angle X-ray diffraction. The crystallite sizes in the lateral directions as well as chain direction increased with spinning speed. In contrast, the imperfaction parameter along the chain axis decreased with take-up velocity. The crystallite sizes of as-spun filaments obtained at 8000m/min were 2 times larger in the chain direction and 1.5 times larger in the lateral directions than those of low speed spun, drawn and annealed fibers. Using the crystallite sizes obtained from wide-angle analysis, small-angle X-ray scattering diagrams were simulated according to the Tsvankin method. The super-structure of high speed spun filaments were estimated as follows. In the range of take-up velocity from 5000 to 6000m/min, the interface between crystalline and amorphous phase in the microfibril is highly inclined with respect to the plane perpendicular to the fiber axis, and in the range from 8000 to 9000m/min, this inclination is rather small, and many voids exists between the microfibrils.
Polyamides and polyester were prepared from tetrafluoroterephthalic acid (TF4) and diamines (hexamethylenediamine, piperazine, p-phenylenediamine and 4, 4′-diaminodiphenyl ether) or bisphenol A by the interfacial or low temperature solution polycondensation. The effect of fluorine substitution on synthesis and properties of these polymers were investigated by comparing with those of the homologous polymers prepared from terephthalic acid (T) or tetrachloroterephthalic acid (TCl4). ηsp/C decreased generally in the order for the polymers from T_??_TF4>TCl4. IR of the polymer from TF4 showed an absorption of C-F bond at 1230cm-1. Tm, measured by DTA decreased in the order T>TCl4>TF4, while the crystallinity estimated by DTA peak area decreased in the order T>TF4>TCl4. Thermal stability of the polymers estimated by TG was found to decrease in the order T>TCl4>TF4. Flame-retardancy estimated by flash-point measurement increased by the fluorine substitution as well as the chlorine one. Solubility of the polymers increased in the following order T<TCl4<TF4. The difference in behaviour between the polymers from TF4 and that from TCl4 can be explained mainly by the smaller van der Waals radius and lower intermolecular cohesion energy of the fluorine atom.
In a series of our studies on improvement of dyeing properties of rayon by the introduction of hydrophobic urethane groups, this study concerns how the fastness to washing is influenced by the modification. The affinities and the diffusion coefficients of four cationic dyes were measured using modified rayon fibers. The fastness was evaluated for the fibers dyed with the cationic dyes and with a disperse dye. The surface property of the modified rayon fibers was assayed by referring to the contact angles of water on cellophane films reacted with the urethanes. The conclusions obtained are summarized as follows: 1. The enhancement of the affinities of the dyes to the modified fibers improves the fastness considerably. 2. The modification results a sizable reduction in the rates of diffusion of the dyes. 3. The enhanced hydrophobicity of the surface of modified rayon scarcely improves the fastness.
Activation volume (ΔV_??_) for the diffusion of p-nitroaniline (pNA) in poly (ethylene terephthalate) (PET) was studied at 100°C from the pressure dependence of the diffusion coefficient (D). The diffusion was carried out under pressures up to 1000bar and in n-butanol (BuOH)/water mixed solvent in which pNA was dissolved. The BuOH concentration in the mixed solvent could be varied in limited ranges because of the immiscibility of the two solvents, from 0 to 6.9% (1st range) and 80 to 100% (2nd range), which could result in a linear increase of the degree of swelling of the polymer in the 1st range, while it almost levelled off in the 2nd range. It was found that ΔV_??_ decreased in a sensitive manner with increase of the BuOH content in the 1st range, giving 92.8 and 26.6 cm3/mol at the BuOH concentration of 0 (pure water) and 6.9%, respectively. In the 2nd range, however, ΔV_??_ was approximately constant, 50cm3/mol. On the other hand, a significant increase of D with increase of BuOH content was obtained in the lst range. Under the atmospheric pressure, for example, D at the BuOH concentration of 6.9% was about 16 times larger than that obtained in pure water. The above relation among ΔV_??_, D and the BuOH concentration was qualitatively explainable from the degree of swelling of the polymer, in relation with the free volume and the occupied volume of pNA molecule (99cm3/mol). A quantitative explanation attempted by using Fujita's theory was not much successful, giving unexplainably large values of f(0, T), β (T) and γ (T).