In the previous report, the compressional pressure-deformation curves of various carded fibre masses and blankets were measured. And they were analysed by the model which consists of m springs in series and the n serial springs in parallel, where n and m depend on deformation x. In this report, considering the rheological character of bended fibres and the frictions between them, the compressional recovery is discussed. It is defined as The result of analysis of pressure deformation curve drives the following equation, where n1 and n2 are n and k1 and k2 are k in 1st and 2nd compression respectively, and θ_??_2 or 3. k is the coefficient of bending fibre's rigidity. The entanglements of fibres in the 1st compression cause the increase of n, from n1 to n2. Assuming a relation between the mean bending force of the fibres and the forces of entanglement points, the number of entanglements in the 1st compression is related to the rheological properties of bending fibres and the distribution of maximum entanglement forces which correspond to static friction force ceofficient.
A calculating method of shifting probability (S) towards the root of animal fibre than towards the tip was studied. It could be calculated easily from _??_a, _??_w, σa2 and σw2, where _??_a and _??_w are mean values of coefficients of friction of anti- and with-scale, and σa2 and σw2 are unbiased valiances of μa and μw. The following relations are discussed; between _??_a and σa, _??_w and σw, (μa-μw) and (μa-μw)/μw, (μa-μw)/μw and (μa-μw)/(μa+μw), S and (μa-μw) and S and (μa-μw)/μw.
Cotton fabrics were acetylated up to a wide degree of substitution by the liquid phase method as reported in this journal (1957) by Sakurada and Sakaguchi. In the present study tensile properties of the fabrics were examined before and after acetylation and it was found that under proper conditions the cotton fabric could be acetylated up to high degree by the liquid phase method without lowering the tensile strength. The preparation method of acetylation bath and its stability, the comparison of various catalyzers and diluents are discussed.
Cotton fabrics, pretreated with acetic acid, were immersed in the acetylation bath, which consists of acetic anhydride and catalyzer, and squeezed to about 60-70% pick-up and then heated in a closed vessel. During these processes the cotton fabrics are acetylated. In this acetylation method, almost all parts of acetic anhydride contained in fabrics are consumed in the reaction and cotton fabrics are acetylated to about 30mol% without lowering the tensile strength in a very short time. This method would be advantageously applied to an industrial continuous acetylation, because the immersion in liquid and the reaction could be finished in an extremely short time.
The paper for capacitor was dried without washing with water after immersed in the aqueous solution of electrolytes, and dielectric loss and electrical resistance were measured at 100°C and 120°C. (1) It is found that the order of mono-valent cations which influenced badly on the dielectric properties is as follows (2) Although the order of Na+ and Li+ is reversed, this order generally agrees with Lyotrope series and the order of ion radius. (3) It seems that the effects of anions on the dielectric properties are smaller than those of cations. (4) When these cations contained in the paper are changed, there are no difinite relations between the dielectric loss and the water-extract conductivity.
Effects of mono-valent cations on dielectric properties of oil-impregnated paper were studied by the same method as that of un-impregnated paper. (1) In the range of this work, effects of mono-valent cations on the dielectric loss at low temperature (about 20°C) is not observed. (2) It is obvious that the order of cations which influences badly on the dielectric properties of oil-impregnated paper is same as that of un-impregnated paper. The order is as follows; (3) In order to compare the dielectric loss of oil-impregnated paper with that of un-impregnated paper, a value of tan δt/tanδu is obtained. Those values of the paper treated with NH4-salts are by far larger than those of the paper treated with other three electrolytes.