The present paper is concerned with deducing the heat setting conditions (temperature and stress) of an elongated P. P. filament, its thermal stress which works on the filament preventing its thermal shrinkage. The thermal stress shows maximum values (f_max•) at a temperature (T_max•) which varies with its thermal shrinkage (%), and satisfies the experimental formula;- f_max•=K(T₀-T_max•), K, T₀: constant. Using this formula, the heat setting conditions of an elongated P. P. filament may be estimated.
1) When only the shrinkage (%) of the P. P. fiber elongated at T°C, which arises due to the relaxation at room temperature, is known the conditions of heat setting may be estimated from the cross point between the straight line connecting the maximum points above expressed and the thermal stress curve of the sample elongated to the known shrinkage (%).
2) When temperature of the heat setting condition of an elongated sample is only known, the conditions may be estimated from the cross point between the straight line and the striaght line which is perpendicular to the setting temperature.
3) When conditions of heat setting on an elongated sample are unknown, first, the thermal relaxation curves which are dependent upon the sum of the thermal relaxation curves of the elongated P. P. fiber (normal stress relaxation curves obtained by heating) and thermal stress curves caused by the secondary bonds unbroken by elongation (especially in low elongation), must be measured.
Increasing its elongation, a curve which is made only by the normal thermal stress relaxation curve, may easily be found and its heat setting conditions may be obtained.

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A theoretical study has been made of the impact fracture of the homogeneous, stringy and Maxwellian material, introducing a concept of limiting elongation.
The theoretical results show that there are three types of fracture of the impacted material, i.e. (1) Instantaneous brittle fracture. (2) Retarded brittle fracture. (3) Ductile fracture. Moreover, it is proved that “instantaneous brittle fracture” is intrinsic by nature, and this will appeares under the follwing condition, where, σ_M, υ, E are impact strength, impact speed and Young's modulus of the material, respectively, while V is the propagation speed of the shock wave in it.

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The tensile strength and the ultimate elongation of an acrylonitrile-methylacrylate copolymeric fiber in wet state were measured at various temperatures under a condition of constant load and compared with the values for dry condition reported previously. Results obtained are summarized as follows:
(1) The time-temperature superposition method applied to the ultimate properties in dry state was also applicable to the results in wet state.
(2) The relation between the shift factor along the logarithmic axis of the time to break in wet state versus temperature followed an equation of the Arrhenius form of which the apparent activation energy showed different values in accordance with the temperature regions below and above 65°C. The apparent activation energy was calculated as 44.0kcal/mol below 65°C, and the value above 65°C was obtained as 73.0kcal/mol which was the same as that obtained in dry state above 80°C.
(3) The curves in wet state and in dry state, plotting the values of the logarithmic shift factor along the logarithmic axis of the ultimate elongation against temperature, showed identical shape and could be reduced to a single curve by using a reduced temperature T-T_c, where T is temperature and T_c is a characteristic temperature. It was obtained from the reduction noted above that the difference between the values of the characteristic temperature in wet state and in dry state was 20°C.
(4) As the characteristic temperature in wet state was determined at 65°C, the value in dry state was obtained as 85°C. The characteristic temperature seems to correspond to the glass transition temperature obtained in each state.
(5) Comparing the composite curves of the tensile strength at the characteristic temperature in wet state with that in dry state, the value of strength in wet state was related as 0.66 times to that in dry state over 8 decades of the time to break. The above result seems to show that a critical condition of rupture in wet state is the same as that in dry state.

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Polyethylene terephthalate monofilaments crystallized by heat-treatment at 150°C were drawn in the silicone oil bath at 180°C. The changes in the fine structure and properties of drawn samples were investigated and the mechanism of the drawing is discussed.
The results obtained are as follows:
1. The heat-crystallized monofilaments are uniformly drawn at different draw ratio until the maximum draw of 5.5. The tenacity and young modulus of the resultant filaments gradually increase with the increase of the draw ratio. The ultimate elongation has the maximum value at the draw ratio of 1.5, and then, gradually decreases.
2. The orientation of (100) plane determined by the X-ray method rapidly increases above the draw ratio of 2.0, and saturates near the draw ratio of 4.0. On the other hand, the birefringence gradually increases with the increase of the draw ratio.
Using these data and the crystallinity, the molecular orientations in crystalline and amorphous regions have been estimated. It is concluded that the crystalline orientation rapidly increases near the draw ratio of 1.5, and saturated near the draw ratio of 4.0, but the molecular orientation in the amorphous region begins to increase at the draw ratio of 2.5 and nearly saturates near the draw ratio of 5.0.
3. Crystallinity determined by the X-ray method shows a minimum at the draw ratio of 2.5 and a maximum near the draw ratio of 3.5 and then decreases.
4. The crystal width determined from the (100) reflection peak shows the maximum at the ratio of 4.0 and that from the (010) reflection peak shows the maximum at the draw ratio of 4.5, respectively. They are extremely larger than those of normally drawn fibers.
5. The long period which is determined from the meridional small angle scattering does not change in the process of the drawing, but the strongest intensity of the peak is at the draw ratio of 3.5.
6. The α-absorption maximum of the mechanical loss tan δ for the drawn fibers of the draw ratio from ca. 1.5 to ca. 2.0 appears at the temperature about 10_??_20°C lower than those of the undrawn fibers. Above the draw ratio of 2.5, the α-absorption maximum gradually shifts to the higher temperature. The drawn filaments of the draw ratio from ca. 2.0 to ca. 2.5 show a maximum contraction by heat-treatment at 160°C and 190°C.
From the above results, the mechanism of the drawing process of the heat-crystallized PET is discussed. When spherulitic structure produced by heat-heatment of the undrawn fibers is slightly drawn, the molecular chain in the amorphous region is elongated at first. Near the draw ratiofrom 1.5 to 2.0, folded molecular chains in a lamella is unfolded and elongated in direction of the applied force and therfore the crystallinity decreases. But when they are elongated to a certain degree, these molecular chains may recrystallize by their intermolecular forces into a bundle type and c axes of the crystallites will align parallel to the fiber axis. When the fiber is further elongated, the fiber structure will be partially destroyed.

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A concentrated aqueous solution of acrylamide was dispersed in carbon tetrachloride using emulsifier, and polymerization was carried out in the emulsion at 30°C by using redox initiator under nitrogen atmospher.
The polymerization proceeded smoothly at the comparatively low temperature without any side reactions, because heat of reaction was readily eliminated by stirring.
Molecular weight of polyacrylamide was able to be easily controlled by adding some chain transfer agent. The chain transfer coefficients of isopropyl alcohol, tert-butyl alcohol and n-dodecyl mercaptane were found to be 2×10^-4, 0.44×10^-4 and 0.90×10^-4 respectively.
Microscopic obserbation showed that fine particles of random forms of polyacrylamide flocculate rapidly to almost globular and porous particles of about 1.5_??_2μ in diameter uniformly at a time the polymerization is near completion.
From the reaction mixture, the polyacrylamide may be precipitated by smaller amount of precipitant such as methanol than that needed in usual solution polymerization, and powder of watersoluble polymer of required molecular weight was obtained conveniently.

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For graft polymerisation of styrene onto wool fibre imbibing solutions of various catalysts, among various methods known for emulsion polymerisation, the redox method is found to be most effective (NaHSO₃-H₂O₂).
It has been supposed that the chemical groups of wool fiber which lead to graft copolymerisation are a consequence of the covalent sulfur bonds present in the wool molecule, but according to the IR spectroscopic research, it was supposed the graft copolymerisation of styrene onto the wool molecule originate from the results of the formation of radicals of structure R-NH, derived from initiator attack at the free amino groups in the presence of the NaHSO₃-H₂O₂ redox system.
The reaction rate of grafting was given by following eouation: dθ/dt=K(100-θ) where θ is the efficiency of grafting, K the reaction rate of grafting, t the time. The activation energy of grafting calculated from the relation between In K and 1/T from Arrhenius equation was 25.2Kcal/mol.
The molecular weight of the grafted polystyren is in the order of 10⁵_??_10⁶ and the mechanical properties (Tensile strength, Elongation, Young's modulus) of styrene grafted wool decreases beyond 100% degree of grafting. The effect of heat setting on the styrene grafted wool fabrics were examined. The degree of grafting of about 30_??_50% were the most effective and above this point these effects decrease.

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In the case of styrene graft copolymerisation onto the wool fibers, the most effective methods were the emulsion polymerisation.
Results obtained are as follows:
1) The reaction rate of graft polymerisation differs from the case of styrene grafting as shown by the following equation. where, θ is the efficiency of grafting of MMA., K the reaction rate constant of grafting, t the time. The apparent activation energy of grafting calculated from the relation between lnK and l/T by Arrhenius equation was 17.5Kcal/mol.
2) The reaction rate constand K depends on the concentration of reducing agent and is proportional to the square root of this concentration.
3) According to the IR spectroscopic study, the characteristic absorption band could be found on the wave number 2950cm^-1 and 2990cm^-1, but not in the position of the graft polymerisation of MMA.
4) The molecular weight of the grafted PMMA is above the order of 10⁵, and the tensile strength increases with the rising degree of grafting, the elongation decreases and the Young's modulus does not change.
5) The effect of heatsetting on the MMA grafted wool fabrics were examined, and the degree of grafting less than 50% were most effective.

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