Radiation coefficients of polyethylene, polystylene, polycarbonate, polyvinylchloride, nylon 6, polyvinylidene chloride, di-acetate and cellulose films were obtained at temperature range of 10° to 50°C using the previously reported equipment. Apparent radiation coefficients of these films are shown in Fig. 9, where those of polypropylene and polyethylene terephthalate films are also shown for comparison. Polyethylene and polypropylene have the smallest value of the radiation coefficient, polystylene has an intermediate value and polycarbonate, polyvinylidene chloride, nylon 6, polyvinyl chloride and PET the highest values. Comparison of the coefficient with the chracter of the film surface, which was observed by electron microscope, showed that unevenness of the surface has no effect on the coefficient.
The effects of the tension in heat setting on the fine structure were studied for nylon 6 fiber. The fine structure is much affected by tension, especially the degree of molecular orientation of amorphous region. The following facts were observed. The tension in heat setting of nylon 6 fibers has no considerable effect on the degree of crystallinity, whereas it exerts influence on the amorphous region. Wide angle X-ray diffraction shows a little change in crystallite orientation after heat setting even though much shrinkage occurs. In the phenol solution of equal concentration, the fibers which the shrink during heat seting swell along fiber axis, though the extended fibers shrink. By this swelling properties, it suggested that some of the molecules in the amorphous region change from the elongated to the folded conformation when the heat is set under zero tension. The diffusion velocity of dye in fiber becomes very low by tension in heat setting, though the saturated amount of dye at equilibrium does not change greatly. The orientation of molecule in amorphous region is increased remarkably by the tension in the heat set. And the diffusion coefficient of dye in fiber has linear relation to the orientation factor of molecule in the amorphous region. The tension given in heat setting has very important bearing upon the dye-ability. These results indicate that it is very important to keep tensile condition exact for heat setting process of nylon 6 fiber.
The wide angle diffraction diagrams of X-ray of nylon 6 were observed at high temperature. The X-ray diffraction apparatus was constructed, in which the samples could be kept at any temperature between room temperature and 300°C. A pre-heat-set sample was prepared by heatsetting at fixed length in the electric oven. In the case of the non-heat-set sample, two diffraction peaks on the equator approached gradually by heating and overlapped each other at 120°C, and its spacing was essentially identical with the spacing of the cylindrical hexagonal structure, 4.3A. The sample heated up above 140°C gives hexagonal pattern, but when the sample was cooled down, the two peaks of diagram separated at 120°C and gave the typical pattern of nylon 6 after cooling down to room temperature. In the case of the pre-heat set samples, two peaks overlapped with each other at higher temperature than in the non-heat-set sample. But when the samples were heated up above 180°C, regadless of the pre and non-heat-set temperature, two peaks of diagram separated from one peak. The effect of heat-setting on the fine structure of nylon 6 fibers is discussed in the relation to the physical behaviors.
It is difficult to spread the repellent agent uniformly on the surface of the substrate using the dilute solution which contains the least amount of repellent agent required theoretically, and the defects in the layer will result in insufficient repellency. Therefore, the excess amount of repellent agent is used for practical treatments. The effects of dilution of the repellent solution and the application of surfactants on waterproofing were investigated, and the following results were obtained; (1) The contact angle between a water drop and cellophane, and its resistance against washing and wearing does not deteriorate untill the concentration of repellent agent decreases to about a tenth of usually applied concentration. Below this range, the fluorochemical agent exhibits more rapid decrease of the contact angle than the silicone. (2) The repellent effects are improved by repeated treatments with the solution of unsufficient concentration. (3) The pretreatment with the solution of surfactant followed by drying over 100°C, recovers the deterioration due to the dilution of repellent agent and this recovery showed maximum between 0.001% and 0.01% of surfactant concentration. At the higher concentration, the levelling effect of surfactant fixed on the surface of substrate might be outweighed by the hydrophilic effect of the surplus surfactant.
The apparent diffusion coefficients D of three acid dyes (Acid Orange 7, Acid Blue 45, Acid Red 99) and one direct dye (Direct Blue 71) in Nylon 6 fiber were determined by the microscopic measurement of the distance of advancing front of dye from fiber surface (x). The following results were obtained: 1. The method applied here was simple in process, but it needs a preliminary experiment before determining D because the method has narrow applicable range. 2. D from this method agreed with that of Hill' s equation, though K is variable with the kind of dyes. 3. It is supposed that the greater the molecular weight andthe nnmber of sulphonic acid group in dyes the larger K becomes.
This paper intends to evaluate the heat of fusion of isotactic polypropylene crystals in monoclinic form by thermal analysis and the method of x-ray diffraction. A whole polymer having viscosityaverage molecular weight _??_v=1.93×105 and three fractions (_??_v=1.47×105, 1.75×105 and 6.31×105, respectively), insoluble in boiling n-heptane, were moulded into 0.1mm thick film, and then, annealed at the temperature ranging from 120°C to 165°C by using the descending temperature method in similar manner as that described in the previous paper (K. Kamide, M. Sanada; Chem. High Polymers, Japan, 24, 662 (1967)). Heat of fusion ΔH, x-ray crystallinity Cx and density were measured on the slowly-cooled film after annealing. From the relationships among ΔH, Cx and density, ΔH=ca 33cal/g for crystals with Cx=100% was obtained irrespective of molecular weight and molecular weight distribution, respectively.
Cellulose acetates with various acetyl values (D. S. 0_??_3.0) were oxidized with NO2 gas, and the amounts of their functional groups were determined by infrared spectrometry. The results are as follows: 1) The determination on the film samples gave more sensitive and accurate results than on the KBr disc samples. 2) The treatment of cellulose acetate with purified NO2 which did not deacetylate the samples, produced carboxyl and nitrate groups in place of hydroxyl groups. The nitration took place rapidly up to 2.7 N % with no futher increase even though hydroxyl groups remained in the samples. 3) Even when a very small amount of H2O was mixed with NO2, the extent of oxidation decreased very much, and the nitration took place considerably. 4) The behavior of the cellulose acetate, which had been saponified below D. S. 1.5 in the reaction with NO2 was almost similar to that of amorphous regenerated cellulose with NO2.