Showing papers in "Sen-i Gakkaishi in 1971"

Experimental estimation of intrinsic birefringence of crystalline and non-crystalline phases in polyvinyl alcohol

Abstract: The total birefringence of crystalline polymer for cylindrical symmetric orientation can be represented as follows; on the basis of simple additivity of the crystalline and non-crystalline contribution.The intrinsic birefringence of uniaxially stretched polyvinyl alcohol are evaluated by simultaneous measurements of x-ray diffraction, visible dichroism and birefringence.We transform the above equation to fallowing equation, and then, the slope and intercept on ordinate, we can evaluate the intrinsic birefringences of crystalline and non-crystalline phases, experimentally.On the other hand, by using of Lorentz-Lorenz's equation, we determine the ratio of the intrinsic birefringence of crystalline and non-crstalline phases, and moreover substitute the ratio into the additive equation of birefringence. The symplified equation can be represented as follows; where Δco is KΔao.This equation shows the linear relation of Δt against Δao, therefore we can determine the intrinsic birefringence of non-crystalline phase from the slope of the line.Employing above two methods in our experimental results, following results are reached.1) The average intrinsic birefringence of crystalline and non-crystalline phases are found as follows; Δco=51.8×10-3 Δao=43.8×10-32) The principal refractive indices of crystalline and non-crystalline phases are found as follows;

Relationship between the structure and the surface state of the simultaneously biaxially stretched poly (ethylene terephthalate) films

Abstract: In this report, the orientation mode in the film plane and the relationship between the molecular structure and the surface state are discussed for the uniaxially stretched and simultaneously biaxially stretched poly (ethylene terephthalate) films prepared by wet-process.Sample films used in this study were the T-die extruded film with 140μ thickness. The uniaxial and the biaxial stretching of the films were done using a film-stretcher in a recirculating hot glycerin bath.The following results were obtained:(1) The crystalline orientation of simultaneously biaxially stretched films was random in the plane, however, that of two-way successively biaxially stretched films was selective to some extent.(2) The selective planar orientation parameter of the simultaneously biaxally stretched films was larger as compared with that of the uniaxially under constant width stretched films, in the machine direction and same stretch ratio.(3) The tautness-parameter of molecular chain in the simultaneously biaxially stretched films was smaller than in the two-way successively biaxially stretched films, but this tendency was reversed by the heat treatment under the fixed length.(4) The size of crystallite in the simultaneously biaxially stretched films was nearly equal in both the machine and the transverse directions.(5) On the electromicroscopic observation, the simultaneously biaxially stretched films with lower stretch ratio showed no charactristic surface structure, however, these films with higher stretch ratio represented the fibril-like structure.The molecular chain is locally uniaxially oriented in various directions in the plane, but the orientation is totally cancelled by averaging in the thickness direction which is due to the multilayer structure. That is, the simultaneously biaxially stretched films shows the uniplanar orientation.

The viscoelastic properties and the dyeabilities of polyester fibers

Abstract: Relations between viscoelastic properties and dyeabilities of disperse dyes in fibers and films of polyethyleneterephthalate and copolyester were investigated in order to study the structure of the fibers and the dyeability. It was shown that the dyeability DY could be well expressed both for homopolyester and copolyester as follows, where k is proportional constant, (tan δ)c the calibrated loss factor and T0 the characteristic temperature determined by the dye and the condition of dyeing. In this equation the characteristic temperature T0 is increased with increase of the molecular weight of the dyes. On the other hand the dyeability DY can be expressed also by dynamic storage moduli E′ at 20°C and the characteristic temperature T0 as follows, where k′ is proportional constant, E′20 and E′T0 the storage moduli respectively at 20°C and T0. These results suggest that the temperature dependence curve of loss factor tan δ can be treated roughly as the distribution curve of the highest order in the texture that can adsorb the dyes.

The orientation evaluation of infrared dichroism in uniaxially stretched polyvinyl alcohol

Abstract: The evaluation of crystalline and non-crystalline orientation factors of PVA film from the data on x-ray diffraction, infrared dichroism, and birefringence is performed, and the following conclusion are obtained:(1) By using experimental result of the infrared dichroism and x-ray diffraction analyses, infrared transition moment angle of a crystalline absorption band can be determined quantitatively The crystalline orientation factor of a uniaxially stretched PVA can be determined quantitatively from infrared dichroism measurements. The transition moment angles Θj, to the crystalline chain axis for the 1141cm-1 band are 81°25′ and 83°25′ for samples annealed at 160°C and 90°C, respectively.(2) The non-crystalline orientation factor com be determined from infrared dichroism of the uniaxially stretched PVA films dyed with Congo Red, by compensating method using non-dyed films The infrared dichroic orientation factor Fam, (I. R) for the 755cm-1 band is in agreement with the non-crystalline orientation factor Fam, (Bir) calculated by assuming that the additivity of birefringence is valid.

The theoretical equation concerned with the radius of helical coil of crimpable fibers and its numerical calculations

Abstract: A radius of crimp is very important properties of self-crimpable fibers. R. H. Brand1) already has reported on the its equation. However the application of this equation to actual fiber is restricted to a special case, because it involves several assumptions. In this report a general equation is derived: under only one assumption that any component of fiber obeys Hooke's law as follows.E: young's modulus, S: shrinkage, ∫c ( ) dA shows area integration.From eq. (1) following equation is get about two component conjugate fiber.Eq. (2) is applicable to bicomponent fibers having any type of cross section, that is circular, rectangular and sheath core.The followings are made clear:(1) Evaluation becomes possible about the radius of self-crimpable fiber which has continuously distributed value of shrinkage and Young's modulus, for example, asymmetrically quenched fiber.(2) Brand's eq. is a special case of our equation when cross section is rectangular, S1, S2_??_1 and p=1.(3) Radius of crimp becomes smaller in the following cases: 1) when the Young's modulus of inside component is lower, 2) when absolute value of shrinkage is larger (the difference of shrinkage makes the radius of crimp smaller) and 3) when the degree of eccentricity is larger in sheath-core fiber.(4) When radius of curvature of boundary line formed by two component, composing circular cross-sectional conjugate fiber, becomes larger, the radius of crimp gets smaller and saturates to the value about three times of radius of fiber.(5) From the application to rubber model coil, a good agreement can be obtained between the calculated values and observed values about radius of crimp.

Graft copolymerization of acrylamide onto microcrystalline cellulose

Abstract: Graft copolymerization of acrylamide onto microcrystalline cellulose “Avicel” was carried out using ceric salt as an initiator. It was found that the total conversion and the grafting ratio increase with increasing concentration of acrylamide, but they decrease with the increase in ceric salt concentration.The rates of both the total conversion and the grafting ratio decreased with the reaction time. The rate of consumption of ceric ion in the reaction with “Avicel” was much faster than with linter pulp and α-methyl-D-glucoside. It is supposed to be attributed to the fact that its molecular weight is low and it contains more end groups. It was also supposed that the graft copolymerization is initiated preferentially at the reducing end groups rather than hydroxyl groups in cellulose. Remarkable difference in reactivity was observed irrespective of the grain size of the sample cellulose. Namely, the reactivity was independent of the apparent surface area of the cellulose grain. Therfore, it was concluded that the reaction occurs in the inside of the cellulose grains, but the results of X-ray diffraction measurement indicated that the graft copolymerization does not occur in the crystalline region of cellulose.

The dyeing properties of polyethylene terephalate fibers in relation to their fine structure

Abstract: The dyeing rate in the early stages and the penetration coefficient of dye were studied on the dyeing of heat set (at a constant length), drawn polyethylene terephthalate fibres with a disperse dye, C. I. Disperse Red 1 in relation to the fine structure of the fibres.Two sets of fibres with draw ratios of 3.3 and 4.0 were used after heat treatment under various conditions.The findings are as follows:Monotonic increases with the temperature of heat treatment have been observed for the penetration coefficient on both sets of fibres and for the dyeing rate on the fibres with a draw ratio of 3.3 However, the dyeing rate on the fibres with a draw ratio of 4.0 showed a minimum in the fiber heatset at 200°C. The penetration coefficient increased linearly while the dyeing rate decreased linearly with the logarithm of the time of heat treatment. Both penetration coefficient and dyeing rate were much higher for the fibres with a draw ratio of 3.3 than for those with a draw ratio of 4.0 heat-treated under the same conditions.The density and the peak height of the small angle X-ray scattering increased, while the gauche content of the ethylenedioxy linkages in amorphous region decreased with the increase of the temperature or time of heat treatment. All of the above three quantities were linearly dependent on the logarithm of the time of heat treatment. Under the same annealing conditions, the fibres of draw ratio 3.3 showed higher value of the peak height of X-ray small angle scattering and the gauche content, compared to the fibres with draw ratio of 4.0.The dependence of the dyeing rate on the heat setting conditions was discussed by using the following equation, where Ct is the amount of dye absorbed in the fibres at time t and will come up to C∞ at equilibrium, r is the radius of the fibres, and D the diffusion coefficient of the dye which is proportional to the penetration coefficient.The penetration coefficient is a function of two structural parameters: the intensity of the X-ray small angle scattering, and the gauche content of ethylenedioxy linkages in the amorphous region. The relation between the above parameters and the morphology of the fibre were discussed with particular stress on the mobility of the polymer chain segments.

Diffusion of naphthalene fast orange 2gs in drawn nylon 6 fibre by msp method

Abstract: The effect of draw ratio on the diffusion of Naphthalene Fast Orange 2GS in nylon 6 has been studied by means of microspectrophotometric (MSP) method.The diffusion coefficient D (c) of the dye in nylon 6 was found to be strongly dependent on dye concentration in the substrate. This concentration dependence of D (c) decreases with a minimum at the draw ratio of 2, and then increases with the increase of draw ratio.The diffusion coefficient at zero concentration of dye Do, the apparent diffusion coefficient by Kramer's method _??_ and the amount of dye adsorbed at equilibrium pass through a maximum at the same draw ratio.The amount of the amino end groups does not change appreciably with drawing.These results are explained by changes, accompanied by drawing of, the fine structure of nylon 6 and the contribution of non-ionic adsorption in dyeing mechanism.

Mechanical properties of polyether-polyester block copolymers composed of poly (oxy-1, 4-buthylene) glycol as polyether comp onent

Abstract: The present investigation was carried out to study the effect of type of polyethers as soft segments upon the physical and fiber properties of polyether-polyester block copolymers obtained by polycondensation.For this purpose, B-PBG block copolymers composed of poly (oxy-1, 4-butylene) glycol (PBG) as a soft segment and-1, 2-polyethylene-1, 2-diphenoxyethane-p, p′-dicarboxylate (B) as a hard segment were prepared and their physical and fiber properties were compared mostly with those of B-PEG block copolymers.The results are summarized as follows:(1) Though the rates of ester-interchange reaction of polyethers with dimethylester (BM) as a polyester component were in the decreasing order of PBG>PEG>PPG, no marked difference was observed in their intrinsic viscosity nubers between resulting B-PBG and B-PEG copolymers. The degrees of polymerization of B-PBG and B-PEG were relatively high, whereas that of B-PPG was low.(2) As for the degree of crystallinity and melting point B-PBG surpassed B-PEG, and this difference increased with the longer polyether chain. This fact might be attributed to the change of compatibilities of polyether chain with polyester chain in the block copolymers.(3) The difference of compatibility affected the state of amorphous region in the block copolymers. Accordingly B-PBG with low compatibility showed lower softening temperature than B-PEG.(4) The mechanical properties of the fibers were influenced by their crystallinity. The fiber from B-PBG 1000 had higher tensile strength and Young's modulus, but lower elasticity and elongation than B-PEG 1540 fiber.(5) T-PBG 1000 using polyethylene-terephthalate (T) as a polyester component had lower melting point, tensile strength and Young's modulus than B-PBG 1000.From the above experimental results, it was found that the physical and fiber properties of polyether-polyester block copolymers were influenced remarkably by the compatibilities between their hard and soft segments.

Drawing mechanism of polyethylene

Abstract: Uniaxial elongation of a commercial polyethylene film having the so-called a-axis orientation along the machine direction was studied in terms of the changes occuring in the crystalline orientation as revealed by the X ray method at small and wide angles and those in the orientation in the disordered region by the shrinkage of the drawn film. The results obtained are as follows: 1) The original “a-axis orientation” tends to the c-axis orientation as the draw ratio (D. R.) is increased beyond the yield point(D. R.=ca. 1.2 at room temperature) but in the intermediate stage up to ca 1.5 of D. R. the two types of orientations coexist. 2) The small angle scattering patterns are always on the meridian throughout the drawing process, implying that lamellae are piled up along the machine (or drawn) direction. 3) In the case of the elongation at room temperature, the X ray long spacing increases first with the increasing D. R., showing a maximum increase of ca. 14%, which corresponds to the macroscopic elongation at the yield point, and then drops gradually. 4) When the film was drawn at higher temperatures (80_??_130°C), a similar maximum in the long spacing appears at higher D. R. and further elongation gives rise to a rapid drop in the long spacing and then to a levelling off in the D. R. range beyond ca. 100_??_120%. This constant long spacing is dependent only on the drawing temperature; the higher the temperature, the higher the long spacing, irrespective of the original spacing, suggesting strongly the melt-recrystallization mechnism occuring in the drawing process. 5) When the film drawn at room temperature, was heated at the fixed length to a given temperature, the long spacing increases up to that of the film drawn at the corresponding high temperature. 6) The contraction of the drawn film on relaxing proceeds rather repidly (ca. within 100 min) even at the room temperature. The equilibrium contraction shows a maximum (ca. 37%) at 110% elongation for the film drawn at room temperature at the rate of 25%/min. A similar maximum, though a smaller contraction, occures at lower elongation for the film drawn at higher temperatures as measured at room temperature, suggesting the relaxation (or the coiling of the disordered tie chains) took place already at the drawing temperature. All the above results suggest that up to the yield point the elongation occurs only in the disordered region (the tie chains) and after the transitional stage where partial melting and reorganization also likely take place, the final steady state (at least locally in the microscopic neck) of the melt-recrystallization is attained, The intermediate transitional stage may cover a wider range of elongation at lower drawing temperature.

Biaxial deformation of spherulite and multi-layer structure in the biaxially stretched polypropylene films

Abstract: In this report effects of spherulite size and of various stretching processes on the characteristics of the deformation and fracture of polypropylene spherulites were investigated at both the room and higher temperature in connection with the stretchability of films. The exfoliatical property of biaxially stretched film is discussed in terms of spherulite deformation.Film containing spherulite of various sizes were prepared by hot-press technique under the various cooling conditions. These films were stretched with the film-stretcher, in the open bath or the hot-air bath. The following stretching methods were adopted: uniaxial stretchings under the free or constant width, and two-way successive or simultaneous biaxial stretchings.The biaxial stretchability is higher in the films with small size spherulites than in the films with large size.The deformation and the fracture mechanisms of spherulite could be phenomelogically classified as follows: (1) brittle break-down, (2) fracture with the cleavage of interfacial boundary, (3) uniaxial plastic deformation, (4) deformation with necking, (5) deformation with pleating, (6) deformation into fibril structure, and (7) biaxial plastic deformation.The characteristis of the deformation and the fracture of spherulites are summarized in Table 1.We have deduced that the appearance of exfoliatical property as mica was owing to the multilayer structure of the spherulite and the planar orientation of molecular chains and crystalls in the film.

The mechanism of absorption of phenol in poly-ethylene terephthalate fibres and the estimation of lateral order distribution by the phenol absorption method

Abstract: 1. The mechanism of absorptionThe absorption isotherms of phenol and the resulting contraction of polyethylene terephthalate (PET) fibres were investigated in relation to their thermal history.The phenol absorption in the drawn yarn heat-treated at 220°C without tension is of the Langmiur type. In the case of as-drawn or low temperature treated samples, the isotherms are not of the Langmiur type and is accompanied by the contractions of samples on absorption. In the IR spectra of absorbed phenol v OH of phenol appears at 3, 468 cm-1, indicating that phenol is absorbed in PET through hydrogen bonding. The results make us to conclude that the true isotherm of phenol on PET fibre should be of Langmiure type. Thus is due to the change of the fine structure with absorption of phenol, that isotherms other than the Langmiur type are observed for samples with certain thermal history. The structural properties of the absorption region are also discussed in relation to i) the total sites available for the absorption, ii) the fraction of gauche form of ethylenedioxy linkage and iii) the peak intensity of X-ray small angle scattering.2. The estimation of the lateral order distributionThe weight fraction of the amorphous region, _??_, which is available for the absorption of phenol from the aqueous solution of a certain concentration x is determined by the equation (2), assuming that the carbonyl groups in the amorphous region are only available for the absorption site and the Langmiur relation between the amount of phenol absorbed in the sample and the concentration in the solution is held at absorption equiribrium. Where M is the number of total site in the unit weight of sample [in equation (2), mg phenol/g sample was used as the unit of M.], m the number of site occupied in the unit weight of sample and K the equiribrium constant of the absorption-which was determined from a Langmiur isotherm of the sample heat-treated at 220°C without tension.In the case of drawn or low temperature treated samples, _??_ has been observed to increase with increasing x due to the fusion of low order region in the samples. The summative mass order curves can be drawn by plotting _??_ against x, if x is assumed to be a measure of order. The lateral order distribution curves are obtained by plotting the slope of the summative curves against the order function x.

Effects of crystallinity on orientation behavior in unially stretched polyvinyl alcohol

Abstract: The orientation behaviors of crystalline and non-crystalline phases of uniaxially stretched PVA dyed with Congo Red, were observed by means of simultaneous measurements of X-ray diffraction, visible dichroic ratio and birefringence.The following results were obtained:1) The orientation behavior of crystallites in the dfferent degree of crystallinity of the polymers, such as higher crystallinity polymers, the preferential orientation of crystallites with stretching, especially at low degrees of stretching, were observed.2) For the stretched specimens at a released state, we could not recognize clearly the effect of crystallinity, through the measurementsof visible dichroic ratio.3) The decrease in crystallinity during the uniaxially stretching, were considerable in the higher degree specimens.4) As a result of the orientation evaluation of crystalline and non-crystalline phases, it was found that the rod floating model is available for the consideration of crystalline orientation behavior.

Abrasion resistance of formalized poly (vinyl alcohol) fibers

Abstract: Abrasion resistance of un-formalized and formalized poly (vinyl alcohol) (PVA) fibers was investigated in a standard state (20°C, 65% R. H.) and in a wet state (20°C) using an abrasion tester in which the stainless steel abradant is slid perpendicularly to the length of a single filament. Mechanical properties such as tensile strength, knot strength and initial modulus were also examined. The measurements were also made on PVA fibers acetalized with glyoxal. The results obtained were as follows:(1) The abrasion resistance in the wet state was lower than that in the dry state for both un-formalized and formalized PVA fibers.(2) The wet abrasion resistance of the formalized products was improved with increased concentration of formaldehyde in a formalization mixture if the samples with the same degree of formalization were compared, whereas the effects of the concentrations of sulfuric acid and sodium sulfate, and of the reaction temperature on the resistance were less significant under the experimental conditions employed. The wet abrasion resistance of the formalized products, from which the cross-linkages, namely intermolecular formal bonds, were removed by treating with dilute sulfuric acid, was almost similar to that of PVA fibers which were reacted with a relatively low concentration of formaldehyde. The wet abrasion resistance of the formalized fibers which were not cross-linked was nearly the same as that of raw PVA fibers (un-formalized) in a relatively low degree of formalization, but increased with increasing formal content in a relatively high degree of formalization. It is supposed from these findings that the wet abrasion resistance of the formalized PVA fibers depends on the content of the intermolecular formal bonds and the overall degree of formalization.(3) The dry abrasion resistance was only slightly affected by the formalization conditions, whereas it tended to decrease with increasing degree of acetalization in the case of PVA fibers acetalized with glyoxal. This indicates that the formation of a large amount of cross-linkages results in a decrease of the dry abrasion resistance.(4) The dependence of the knot strength of the formalized PVA fibers on the reaction conditions may be acounted for by the intermolecular formal bond formation during the formalization.

Nonlinear stress relaxation behavior of polyethylene

Abstract: Stress relaxation measurements under various strain from 1 to 5%, have been carried out for polyethylene films having different degree of crystallinity at various temperatures from -20°C to near melting point.Stress relaxation modulus can be described approximately by a power series polynomial in strain. Validity of time-temperature superposition for the coefficients Fn(t) of polynomial have been examined (n=1, 2 for low density and n=1, 2, 3 for high density polyethylene). The stress relaxation master curves of Fn (t) were obtained by a digital computer by means of the mini-max method in a temperature range of -20°C to 60°C for low density and to 110°C for high density sample. Temperature dependence of shift factor aT gave two straight lines, when plotted in log aT vs 1/T, intersecting at about 40°C for low density and 70°C for high density sample. The master curves of the first coefficient F1 (t) were compared with the results of the linear viscoelastic region obtained by Fujino and others. It was found that there were good agreement between both curves. These facts suggest that the relaxation mechanism observed for the nonlinear region seemes to be same as that of the linear region.

On the thermal properties of sericin

Abstract: Thermal properties of sericin prepared by various methods were investigated by means of X-ray diffraction, Infrared spectroscopy, DTA and ultramicro-electrophoresis.The following results were obtained.1) On X-ray and IR-spectrum studies no significant difference was observed among sericin fractions prepared by modified Mosher methods with various times and temperatures. But the isoelectric points differed a little among these sample, and the isoelectric point of A-fraction prepared with shorter time was in an alkaline side compared to those of others.2) The thermal decomposition of sericins began to occur at 200_??_220°C. In an earlier stage of decomposition, the increase of absorption intensity of 1720cm-1 and the decrease of solubility were observed. The absorption intensities at 1230cm-1 and 1060cm-1 and the absorption intensity ratio of Amide (II/I) remarkably decreased when the crystallites were broken.3) The sericins prepared by modified Mosher method decomposed thermally at about 260_??_270°C. The decomposition temperature of B-fractions were about 10°C higher than those of A-fractions and that of sericin prepared with the shortest time was about 10°C lower than those of others.4) The cocoon layer of nd silkworm decomposed thermally at 258°C, but its powder had double endothermic peaks at 232°C and 266°C as well as the sericins prepared by modified Mosher methods.5) The sericin extracted from the silkgland of nd×Taizo silkworm had double endothermic peaks at 286°C and 308°C. These correspond to the patial degradation and the weak crystal transition.6) The sericin separated by stirring aqueous silk protein solution showed β-structure, and the thermal decomposition occured at 314°C.From the above results, it is concluded that the decomposition temperatures depends on the crystallinity, and the sericins prepared from the silkgland and aqueous silk protein solution shows higher decomposition temperature due to contamination of fibroin.

The reaction of silk fibroin single fibers with some transition bivalent metal ammine complexes in aqueous solution

Abstract: The single fibers of silk fibroin were treated with various transition bivalent metal ammine complexes in solution under various conditions, i. e. pH and ion concentration in the bath, treating temperature, species of anion and metal ion, such as copper (II), nickel (II), zinc(II) and silver (I). Adsorbed amounts of metal ion for fibroin fiber were determined by atomic absorption analysis. For the structural analysis, the following methods were used: X-ray diffraction infrared spectra, optical microscopy, load-extention, thermal gravimetric analysis (TGA) and difierential thermal analysis (DTA). The results are as follows;(1) Adsorbed amounts of metal ion for silk fibroin single fiber treated with metal ammine complexes in aqueous solution were larger in comparison with those treated with metal nitrate at lower pH. (2) X-ray diffraction studies showed that the decrystallization of silkfibroin occurs during the treatment. (3) Tensile strength and elongation of the fibroin decreases after the treatment. (4) Silk fibers treated with metal amine complexes were more stable thermally than those untreated. The heat stabilities of silk fibroin treated with various transition bivalent metal amine complexes aqueous solution change depending on the kinds of metal ion, and the effect is ordered as follows: Ag (I)>Cu (II)>Ni (II)>Zn (II).

Equilibrium adsorption of disperse dyes from alcohols

Abstract: In order to obtain some fundamental data on disperse dyeing from alcohols, the equilibrium adsorption is discussed from the view points of isotherm, partition coefficient and solubility.Cellulose acetate fibere was dyed in the n-alcohol solutions of three disperse dyes at the temperature from 30°C to 60°C.The solubilities of the dyes in the alcohols were measured at the same temperature range.The results are as follows;1) The adsorption isotherms are well represented by straight lines passing through the origin and the distribution law is confirmed, as shown previously4), 13).2) Various n-alcohols behave similarly to each other as a medium. In this case, there is no relationship between the solubility and the partition coefficient, whereas the following relation is found between the heat of solution (ΔHsoln.) and the heat of dyeing (ΔHdyeing), ΔHdyeing+a•ΔHsoln.=const where a is the constant for a given dye.

An apparatus for measurements of bending friction of yarn and experimental results on spun yarns

Abstract: It was difficult to measure the bending friction of fiber and yarn at arbitrary angle and also to measure it continuously. So, an apparatus to measure friction of spun yarn in contact with a cylinder is devised and experiments are carried out on several kinds of spun yarn. Moreover, on the basis of those experimental data, a study is made on the frictional mechanism of spun yarn.The results obtained are as follow:1) The apparatus measures the frictional force or friction coefficient of spun yarn in contact with a cylinder, changing the angle from 0° to 180° and also the velocity.2) The frictional force or friction coefficient of spun yarn is dependent upon the change of contact length and contact width of spun yarn on a cylinder.It is pointed out in other report that the contact width changes with yarn diameter, the number of twists, fineness, fiber length, friction coefficient of fiber and dead weight in measuring.

The influence of colour on the luster of fabric

Abstract: In the case of high lustrous fabric such as satain weave, it is indicated by Nakazato and Sugiyama that the relation between the luster and the colour (Y value) of fabric is inversed compared with that for non-metaric material, and the visual luster has a negative cprrelation to the contrast gloss. The present paper deals mainly with the reason why such a phenomenon takes place in the fabric.The results obtained are as follows:(I) It is confirmed that the observations by Nakazato and Sugiyama are agreeable.(II) The influence of colour on fabric luster are characterized by. directional properties of internal reflection of fabric.(III) Since the luster of coloured fabrics is not adequately expressed by the equation given previously, new method is proposed on the basis of result (2) M; Regular reflection of fabric Iγ; Internal reflection of fabric D; Diffusion of fabric DM; Diffusion of mat supface α; Constant

On the thermal stress of drwn fibers

Abstract: A parallel spring model is proposed in order to discuss the thermal stress of drawn fibers. It is composed of N springs, each of which is fixed by a hook and bears a force in proportion to the strain. Since some springs are stretched and others are contracted, the total force of these springs is zero in a equilibrium state. With increased temperature some of springs detach from the hook and lose the force.We assume here that the strain of springs is distributed and the spring detaches from the hook in the order of the rate of contraction, ie. the higher the contraction, the lower is the temperature at which the detaching occurs. Detaching from the hook of the contractive springs causes decrease in the extensile force and causes the contractive force in this model. This contractive force is a function of temperature. We calculated the function from this model.The behaviors expected from this model are as follows:1) The thermal stress-temperature relation is parabolic.2) The relation between maximum thermal stress and temerature is parabolic when the cramp length varies.3) The thermal stress-temperature relation varies with a strain distribution of the spring.

Preferential absorption of dye to the higher order amorphous region

Abstract: Synopsis Dye dichroism can be used to determine the mean amorphous orientation. For this purpose, absorbed dyes must be dispersed uniformly in a whole amorphous region. This uniform dispersion may not always occurs in all cases. When the oriented cellulose and polyvinyl alcohol films are dyed with direct dichroic dyes, small amounts of dye molecules are absorbed preferentially into the higher order region of the polymer chain. With an increase of amount, dye molecules disperse uniformly in the whole amorphous region and the obserbed dichroism approaches to the mean amorphous orientation. But, the dye molecule of longer length has a lower preferential absorption. The preferential absorption phenomena relates to the affinity of dye to polymer and to the steric hindrance of dye diffusion into the narrow gaps of the higher order polymer chains. The study of dichroism of polymer at low content values of the dichroic dye may be useful for obtaining information on the lateral order of amorphous polymer chains. Conversely, to determin the mean amorphous orientation, the lower concentration dyeing must be avoided.

Influences of texture on the fabric luster (quality)

Abstract: In the previous paper, the quality of luster of fabrics was discussed from the standpoint of a heap filmIn this paper, it is discussed mainly the influences of texture on the fabric luster (quality)The results obtained are as follows:1 The luster (quality) of textured surface is equal to that of the plane excluding the texture of fabric, when the size of textures is larger than the analytical ability of human eyes, while, when the size is beyond the abitity, it is determined by ∑ (reflecting distribution of texture)2 In fabrics, the parallel property of fiber affects the fabric luster This is caused by the change of directional properties of reflecting elements at the boundary of fiber and air relating with parallel property of fiber3 The relation between the luster of satain weave and of heap films which is asumed to have a plane excluding the texture of fabric becomes clear in this studyThe quality of luster is expressed on the same coodinate system as that of plane materials

Diffusion of naphthalene fast orange 2 gs in heat-treated nylon 6 fibre by msp method

Abstract: The effect of heat-treatment on diffusion of Naphthalene Fast Orange 2 GS in nylon 6 has been studied by means of microspectrophotometric (MSP) method, While the apparent diffusion coefficient by Kramer's method _??_ exhibits a minimum at 170°C, the concentration dependence of diffusion coefficient D (c) decreases with rising temperature of dryheat-treatment.Dry-heat-treated nylon 6 adsorbs less dyes at equilibrium in the middle region of pH than untreated one does, corresponding with the change of the amount of amino end groups, but the amount of adsorption in the higher pH increases by treatment.In the steam-heat treatment, both the _??_ and the D (c) increase, but the concentration dependence decreases. The higher the treating temperature becomes, the more remarkable these tendencies become.The amount of the amino end groups does not change regardless of steam-heating, A possible explanation on these results is discussed.