Blend fibers of polypropylene (hereafter “PP”) and polyamide 6 (hereafter “PA6”) having various molecular weights were prepared by the melt spinning and drawing processes. Effect of the viscosity ratio of the polymers on the structure of the blend fibers were examined. For the undrawn PP fibers, the crystal orientation was very low even at a draft ratio of about 6.0. On the contrary, the undrawn blend fibers having a viscosity ratio (η PP/η PA6) of 1 and lower was found to have the oriented PP crystals even at a draft ratio of 2.0 to 4.0. The drawn blend fibers having a viscosity ratio of 1 and higher exhibited stronger and more distinct X-ray diffraction peaks of the PA6 crystals as compared with the blend fibers having a viscosity ratio of 1 and lower. An unusual phenomenon was observed in the DSC measurement of the drawn blend fibers: two melting endothermic peaks of the PA6 component appeared for the fibers with a viscosity ratio of 1 and lower. It was speculated that the imperfect and small PA6 crystallites were formed because of the inflluence of the PP component. The significant changes observed in the crystal orientation and the melting endothermic behavior in the blend fibers was considered to depend largely on the dispersion state of the PP and PA6 phases: when the viscosity ratio was lower than 1, the two phases are finely dispersed. On the ohter hand, when the viscosity ratio is high than 1, the phases are coarsely dispersed and the interaction between two phases are relatively low.
We intended to clarify the relationship among supermolecular structure and physical properties and birefringence (Δn) due to the diffusion of solvent molecules into cuprammonium regenerated cellulose fibers. The samples employed were two kinds of cellulose hollow fibers whose pore structure had been well-investigated. The structure was evaluated through the wall thickness, the length, and the refractive index of those fibers. The physical properties were represented by a degree of the shrinkage and the dynamic viscoelasticities. The region of diffusion of solvent molecules was investigated by the temperature dependence of dynamic viscoelasticities and the value of Δn in a solvent. The results were as follows: The orientation of the crystal plane (101) (and/or the working direction of the intermolecular hydrogen bond in a noncrystalline region) depended on the coagulation solvent used in their preparation. The change in Δn due to the adsorption/desorption treatment with a solvent was explained by the deformation of the primary particle composing the hollow fibers. Water and methanol molecules could diffuse into the intra-primary particle with an ellipsoidal shape and deformed the particle to spherical shape. For hydrophobic solvents, the similar deformation scarcely occurred. Each solvent diffused into its characteristic region and accelerated the thermal molecular motion in this region. Consequently, the change in supermolecular structure can be evaluated quantitatively through the value of Δn measured in a solvent, and the change was governed by the broadness of the region of diffusion of the solvent molecule.
Lipase-catalyzed transesterification of 2, 3-epoxy-l-propanol (glycidol) with viny acrylate was carried out to synthesize glycidyl acrylate (GA) in organic solvents. Lipase PS was the most appropriate enzyme for the synthesis of GA among three kinds of lipases studied. While the initial rate of reaction was fast in hydrophobic solvents such as toluene and isooctane, the conversion after 4h was almost same in toluene and in hydrophilic tert-amyl alcohol. Initial rate of the reaction in tert-amyl alcohol increased by the addition of small amount of water, neutral polymeric surfactants, poly (ethylene glycol), and poly (N-vinyl pyrrolidone) (PVP). The conversion increased further when lipase-PVP complex was previously formed.
The relation between the change in moisture content during the measurement of B-value and the moisture sorption-desorption isotherm was studied for the moisture sensitive textiles of cotton fabric, woollen fabric and NF-38 non-woven fabric. The change of the moisture content in a closed vessel under periodic change of temperature between T1 and T2 agreed well with the difference between the moisture contents along the moisture sorption isotherm at lower temperature T1 and desorption isotherm at higher temperature T2. The calculated relation curve, based on this finding, between B-value and weight of each textile for the volume of a closed vessel agreed well with the observed one. This means the textiles having the desired B-value can be designed from the moisture sorption-desorption isotherm of the constituent fibers.
Deaerated water is used in many industrial fields because of its high permeable property. We proposed the reason for this, as being the ability to dissolve the gas trapped in tiny narrow voids on textile surfaces. This mechanism was confirmed by density measurement using a density gradient column of aqueous salt solution.
The shapes of meshes and laces were analyzed by means of a fractal geometry technique and simulated by fractal images such as a Sierpinski gasket, a Sierpinski carpet and their modified images. The image analyses of meshes, needlepoint laces, bobbin laces, and their models were discussed in detail. The followings were found: the renge of dimensions of the needlepoint laces and the bobbin laces were inbetween 1.5849 (the dimension of the Sierpinski gasket) and 2-dimensions. The correlation coefficients were lager than 0.999, accordingly the shape of the laces was a random fractal set, which is a kind of statistically self-similar obect. The geometric model of “Point couppe”, the origin of the needle laces which can be prepared by cutting a two dimensional cloth, corresponded to the Sierpinski carpet which has the dimension of about 1.9. In the course of the development of needlepoint laces from the “point couppe” to “reticellas”, which is made by using a grid of plaited threads instead of the residue of woven fabric to give larger and more openings and to give more delicate impression, and aurther to “punto-in-aria” which is called “the lace in the air” becase of its delicate appearance, it was found that the dimension changed from that of the cloth to that of the Sierpinski gasket, that is, from 2 to 1.5489.
This paper explores a technique for estimating a wool yarn counting no contact with a yarn by an image processing and a discriminant analysis. A ring halogen light illuminated a yarn drawn by a initial tension. The yarn image was photographed by a microscope and a Charge-Coupled Device (CCD) monochrome camera and the binary image of yarn was obtained by a smooth processing and a binarization for an input image. Each yarn width of obtained image was measured automatically. The relationship between the yarn counting and the measured yarn width was analyzed by a discriminant analysis. Using the discriminant value, the yarn counting could be estimated in the high discrimination ratio.
A Curie-point pyrolyzer directly coupled to a capillary gas chromatograph was applied to analyze the pyrolytic behavior of phosphate derivatives of β-cyclodextrin, amylose and cellulose. It was found that the amount of levoglucosan detected on each pyrograms depends on the degree of substitution of the constituent glucose unit. These pyrograms were compared with those of Proban® as a typical flame retardant cellulose fiber available in commercial use. It was shown that the efficiency of flame retardant treatment on cellulose fibers could be evaluated by this type of analysis with a little amount of samples as 0.1_??_0.3 mg.
Cotton fabrics were treated with a mixture of water soluble silk fibroin and 1, 2, 3, 4-butanetetracarboxylic acid and a mixture of water soluble silk fibroin and urethane resin. The crease recoverability, water absorption and photoyellowing behavior due to ultraviolet irradiation were investigated for treated fabrics. The crease recovery of the fabrics was enhanced and the water absorption was reduced by the treatment with the mixture of water soluble silk fibroin and 1, 2, 3, 4-butanetetracarboxylic acid suggesting the occurrence of crosslinking between the cotton fibrils. The photoyellowing of silk fibroin was suppressed by the urethane resin.
It has been suggested that positively charged membranes are very effective to eliminate phosphate from blood in dialysis for patients. However, this type of hollow fiber membranes have been pointed out to bring about several problems, such as thrombus formation or hemolysis. In this paper, the ion transport across a membrane was computationally examined in the system of multicomponent dialyzer. In this calculation, partition and diffusion coefficients of phosphate ion were used as parameters. The efficiency of phosphate elimination could be increased even for membranes with negative charges.