Various kinds of high tenacity rayons were fatigued to various extents with Ferry Vibration Tester.
In the swelliug mediums that is, R. H. 65%, water and NaOH solutions of various concentrations, the stress-strain curves of fatigued and original samples were determined to observe the differences between two samples, and the fatigue mechanisms of high tenacity rayons are discussed from the viewpoint of fine structure.
When the fibers are fatigued the following appeares in the stress-strain curves:
1. Increase of molecular chain orientation.
2. Relaxation of cohesive bonds by chain scission or slippage.
3. Macro-inhomogeneities by the occurrence of weak points or cracks.
The change of the fine structures of fibers by fatigue is generally discussed, as well as on the experimental results of static fatigue. From the results, when high tenacity rayons are fatigued by dynamic or static methods, it is concluded that fatigue proceeds in the order of the following;
1. Destruction in amorphous regions
2. Destruction in crystalline regions
3. Breakage of molecular chains.

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In various stages of spinning process of high tenacity rayons, stretch was varied, and cohesive bonds formed in the process were investigated by determining the stress-strain curves in various mediums.
The results obtained are as follows:
1. The stretch effects were not good in the first bath or between the first and the second baths. Perhaps the cohesive bonds formed were so weak that the stretched cohesive bonds would be relaxed.
2. The effect of stretch in the second bath was nearly perfect.
3. Stretch after the second bath or in the drying stage did not have the effects on higher cohesive regions.
It was estimated that the stretch between the second bath and the drying stage had only a little effect on the degree of chain penetration through crystallites or on the uniformity of chain length between crystallites. Therefore, it is considered necessary to control the stretch in or before the second bath in spinning process.

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It is expected that recrystallization during acid hydrolysis of cellulose fibers can be inhibited to some extent by previously increasing accessibility of the fibers to acid hydrolysis, that is by splitting of the chain molecule and degradating of the morphological structure without rearrangement during the pretreatment. The effect of prealcoholysis as the pretreatment was investigated.
A commercial viscose grade pine sulfite pulp was prealcoholyzed with 1.0 N-HCl in absolute methanol, ethanol, and n-propanol at the boiling point respectively, washed, and then without drying, subjected to acid hydrolysis with 3.5N-aq. HCI at 100°C. Amount of highly ordered regions (crystallinity estimated by acid hydrolysis method) and leveling off degree of polymerization were determined to compare the inhibiting effects of alcohols.
Prealcoholysis is effective for inhibiting recrystallization during acid hydrolysis. Among the three, ethanolysis is most preferable for the purpose, at least practically, because methanolysis seems to allow considerable recrystalliztion by itself. Propanolysis may proceed in excess topochemically, and besides propanolyzed residues retains brown color even after the successive hydrolysis is applied. It was sufficient to preethanolyze for 30 min. under the experimental conditions. Prealcoholysis is effective also to prevent humification during hydrolysis.
Hydrocellulose obtained by preethanolysis for 1/2 hr and successive hydrolysis for 1/2 hr contained no molecule of degree of polymerization over 300, while hydrocellulose obtained by hydrolysis for 2 1/2 hr without the pretreatment contained molecules of degree of polymerization over 500.

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The solubility of sericin of different kinds of cocoon layers caused by the action of boiling water is estimated by the quantitative analysis of nitrogen, and refering to the quantity of dissolved sericin x (%), an experimental formula x=ct^b is obtained, from which the velocity of dissolution is: derived as follows: dx/dt=bx/t, where t represents the boiling time and b and c are constant numbers.
But the velocity is also expressed, as a function of the remaining quantity of sericin (a-x) (%), by another formula dx/dt=k (a-x)ⁿ, where k is a velocity constant and n an integer taking 2_??_4, and not 1.
Throughout these formulae, the authors conclude that the two kinds of sericin fractions are contained in the cocoon layers showing the discontinuous solubility, and discuss about the fact that the velocity of dissolution may be expressed as a high power function in the remaining quantity of sericin.

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With chemical change of CN group to amide and carboxyl group by heating the spinning solution, maximum stretching ratio of spun fibers increase, thereby tensile strength increases and elongation increases, too.
But, in case of the extreme chemical change of polymer, the fiber produced from it causes to the agglutinate in boiling water and loses the resistance for hot water.
With the chemical change to CONH₂ and COOH groups from CN group, the affinity for cationic or disperse dye and the shrinkage of fiber increase in boiling water or in air of high temperature. The elastic recovery of elongation and Young's modulus indicate the maximum value at the state of suitable chemical change of polymer.
The polymer having SO₃H group indicates the affinity for cationic dyes as at lower PH as at higher PH of dyeing solution, but on the other hand the polymer having COOH group can not indicate the affinity for cationic dyes at lower PH of dyeing solution.

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The classificatory mechanism by pneumatical action at the taker-in cylinder part of the flat carding engine (D-type) consists of centrifugal, curved and climbing air current, so the lints and trashes can be classified by centrifugal force, gravity, inertia force and buoyancy.
As a result of the qualitative investigations using the smoke-stream line, the following were observed:
1. Air current within the limits less than 100mm from the inside of the both frames is to be excluded from the ordinary pneumatical action.
2. As a result of this investigation concerning each variable time, it is possible to regard these streams as the quadric co-ordinatins streams.
An example of the measuring values of the speed of currents concerning the centrifugal currents around the taker-in cylinder and the currents along the back surface of the mote knife, are showed by Fig. 6. As a results of those measuring under the experimental conditions, the following were observed:
1. The tangential velocity of the centrifugal currents V_t is calculated from the following experimental formula;
where, U₀, L_c and h_c are circular velocity of taker-in cylinder, circular length from gauge point between dish plates nose and taker-in cylinder, and distance from surface of taker-in cylinder respectively.
4. V_r, the radial velocity of the centrifugal currents, is calculated from the following experimental formula;
3. V_s, the component of velocity in the direction of the back surface of the mote knife concerning the currents along its back surface, is calculated from the following experimental formula;
where, h, α₂, β₃ and V_??_ are distance from back surface of mote knife, coefficient and exponent concerning circular velocity of taker-in cylinder and length from gauge point of mote knife, and component of velocity in direction of back surface of mote knife on line between centrifugal currents and currents along back surface of the knife.
4. θ_s, the angle to the back surface of the mote knife, of the currents along the back surface of the knife, is calculated from the following experimental formula;
where, k₂ and m₂ are coefficient and exponent concerning circular velocity of taker-in cylinder and length from gauge point of the mote knife.

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