Thermal degradation behaviors of nylon 4 homopolymer, a polymer which the chain end of nylon 4 was modified with diamine, and a copolymer containing nylon 4 were investigated by thermal gravimetric analysis at various heating rates. The copolymer (content of nylon 4, 23.5 mole-%) was prepared by anionic copolymerization of α-pyrrolidone and ε-caprolactam. Nylon 4 became more decomposable with a process of degradation reaction. The activation energy of thermal degradation of the polymer was 28-31 kcal/mole, which was smaller than that of nylon 6. The activation energy in the initial stage of degradation depends on the temperature at which degradation of the polymers starts. Thermal stability of the nylon 4 which chain end was modified with bis (p-aminocyclohexyl)-methane increased with rising the temperature of treatment, but its molecular weight remarkably decreased. Thermal stability of the copolymer was considerably superior to that of nylon 4, and in contrast with nylon 4 the copolymer became more non-decomposable with a process of degradation reaction. The degradation reaction proceeded even over the range of nylon 4 contained in the copolymer, indicating occurrence of the degradation reaction of nylon 6 in the main chain of the copolymer.
Light fastness of poly (ethylene terephthalate) (PET) fibers to which vinyl monomers were grafted by a chemical method was estimated by discoloration due to UV-irradiation. The estimation of discoloration was carried out for undyed or dyed samples. When monochlorobenzene (MCB) was used as a co-reagent for the grafting, the light fastness of the grafted PET decreased. After extraction of homopolymer or dyeing, however, the amount of MCB remained in the grafted PET became so small as to give a negligible influence of MCB on the light fastness. It was found that the light fastness of the dyed grafted PET does not depend on the grafting itself and specific light absorbance of the grafted vinyl polymer, but on moisture regain caused by the grafting. Namely, the light fastness of the dyed grafted PET decreased with increasing moisture regain. The hygroscopic functional groups in the grafted polymer gave a peculiar effect on the decrease of light fastness. The carboxyl group and its metal salt had a tendency to decrease the light fastness more than the amide group. The carboxylic acid salts of transition metals brought particularly low light fastness.
The diffusion profiles of Orange II (C. I. Acid Orange 7), Roccelline (C. I. Acid Red 88), and sodium 1-amino-4-n-butylaminoanthraquinone-2-sulfonate (B-IV) in nylon film-rolls were obtained at pH 3 and 90°C under the conditions that the rolls were contact with solutions containing a dye and a sodium n-alkylsulfate (SAS). Five kinds of SAS, such as octyl, decyl, dodecyl (SLS), tetradecyl (STS) and hexadecyl (SHS), were examined in this study. Diffusion profiles of binary mixtures were found to be categorized to four types; sigmoid, box, overdyeing and desorption. The desorption type was solely observed in the mixture diffusion of Orange II with STS or SHS. This suggests that the STS and SHS have high affinity on nylon. Diffusion profiles were markedly affected by the affinity and the concentration of both dyes and SAS's in the dye-bath. It was found that the amount of the dye diffused into film-rolls decreased with increasing the affinity and the concentration of SAS's in the bath. The diffusion coefficients of SLS and STS were estimated to be comparable to that of Orange II, and that of SHS was to that of B-IV. At the same time, diffusion profiles of Orange II in the presence of both SLS and SHS were obtained over 30 to 180 minutes.
A motion diagram showing the relative motion of various machine parts is necessary in order to fully understand, whether the machine properly fulfills its functions. However, in the case of a sewing machine, conventional motion diagrams for both the machine and sewing thread are usually used. This suggests that only a part of the sewing thread motions is given in connection with the machine motion. In this paper, new sewing thread motion diagrams involving various sewing factors such as fabric thickness, stitch length, and thread elongation are proposed for a lockstitch sewing machine. By using the new motion diagrams, it is shown that the relation between needle thread movement and tension changes during one cycle of sewing. It is also shown how the various sewing factors affect the tightening of stitches in the process of stitch formation.
Complex formation of the fibroin (Bombyx mori) containing random coil or antiparallel β structure with Cu (II) ions was carried out under Tcu2+/THL (molar ratio of reacting species) =0.1 at 25°C in an aqueous solution. The aqueous solution of β-form fibroin was prepared by adding 30% (v/v) EtOH and then removing by dialysis. In the absorbance at 540nm, which based on the Cu (II) (N4) planar chelated structure of complex formed in the pH range above 8.5, β-form fibroin was less than random coil fibroin in the pH range 8.5_??_9.5. In the pH titration too, the same phenomenon was given in the pH range 5.5_??_8.0, as a result, the rate of gelation was higher. The observation of these indicates that β structure is inhibitory to complex formation in the pH range above 8.5, on the contrary, favorable for it below 8.5.