Fixation of chitosan on cotton and poly (ethylene telephthalate) (PET) fabrics irradiated with ultraviolet (UV) light was studied. The amount of chitosan fixed on UV-irradiated fabrics was found to be appreciably higher than that on fabrics that did not undergo irradiation. In comparing the fixation of chitosan on chemically oxidized cotton fabrics that contain large amounts of aldehydes and carboxyl groups, it can be deduced that electrostatic interactions between chitosan and carboxyl groups formed on the UV-irradiated fabrics may be involved in the fixation reaction. We were able to obtain chitosan fixation durable enough to withstand washing. A similar fixation effect was also observed on fabrics that were treated with low temperature air plasma.
An attempt was made to clarify the influence of drawing on solid structure and the fibrillation tendency for cuprammonium rayon, as a model of regenerated cellulose fibers. The drawing was carried out for the gel-like fiber obtained after coagulation (drawing at coagulation) and at the regeneration process of the coagulated fiber (drawing at regeneration). In the case of drawing at coagulation, the fibrillation tendency, degree of crystallite orientation (fc), and birefringence (Δn) increased, and the peak temperature of α2 dispersion (Tmaxα2) and tanαvalue (tanαmaxα2), which are the parameters representing the density and the amount of the amorphous region, respectively, decreased with drawing ratio. On the other hand, for drawing at regeneration, only fc showed very low drawing ratio dependence, while the influence of drawing on other factors was same as the case of the drawing of coagulation. The coagulated fiber with constant length showed remarkable stress relaxation at regeneration process. From these results we considered that in the case of drawing at coagulation, both crystal and amorphous phases increased in their orientation degree by drawing, because of the presence of network structure formed by cellulose-copper (II) complex. During the regeneration, such network structure is cleaved by the sulfric acid, as a regeneration reagent. Therefore the crystallization occurs under less tension than that at coagulation process and the drawing at this process may mainly lead to the orientation of cellulose molecules in amorphous region. The drawing at coagulation and regeneration processes was inferred to make remarkable break-down of bondings between fibrils, which may results in an increase of fibrillation tendency.
Nylon 6 filament (φ5=900μm) was dyed with aqueous dispersion of two different dispere dyes, one of which is azobenzene based and the other is anthraquinone based, at 40°C, 60°C and 80°C and the concentration gradient of the dye molecules penetrated along and perpendicular to the fiber axis were determined by an optical microscopy and a microspectrophotometry. The rates of penetration of both dyes penetrated starting at the sliced cross section then diffusing along the fiber axis (=D_??_) at three different temperatures were compared with those penetrated laterally through the surface of the filament (=D_??_), respectively on each profiles of relative dye concentration (=Absorbance)-penetrated distance. It was found that D_??_ is about three times faster than D_??_ for the nylon filament examined in this study. Taking into account of the glass transition temperature of solid nylon 6 is of the order of 70°C, it was confirmed that, at 40°C, both dyes are effective to give colored texture only at the periphery of the filament. At 60°C, it is seen distinct differences between the profiles of dye concentration-penetrated distance for both dyes. The dye bath temperature about 80°C is adequate to give distinct differences between those profiles as Disperse Blue 3 tends to an equilibrium showing homogeneous coloration throughout the texture while Disperse Red 1 attains another type of equilibrium having rather wide spreaded concentration gradient with an absorption maximum. It was also confirmed on these profiles that the highest dye concentration (=absorption maximum) is not found at zero distance. i.e., at the periphery of the sample filament but appears at the interior part of about 100_??_200μm from the surface.
The twist for circuit boards containing aramid fibers was investigated from the viewpoint of the thermal shrinkage caused by their fiber orientation. Fiber orientation was measured by microwave method, which is based on the dielectric anisotropy. It was confirmed that the fiber orientation could be estimated from the dielectric anisotropy of samples. The dielectric anisotropy measured by microwave method for uniaxially oriented glass fibers was in good agreement with the law of mixture, which shows the appearance of dielectric anisotropy caused by the shape of island (fiber) in the islands-sea structure. On the other hand, the ratio of coefficient of thermal expansion against the orientation degree by microwave method was studied by thermomechanical analysis. Calculated results by our proposed model for the twist of circuit boards were in good agreement with values measured on Japanese Industrial Standard. In order to minimize the twist of two-ply circuit board, the orientation degrees should be minimum or orientation angles of two ply should be the same.
Industrially available bisphenol A polyarylate is conventionally produced by interfacial condensation polymerization of bisphenol A and a mixture of terephthloyl/isophthaloyl chlorides. We now report a new synthetic method without using the acid chloride derivatives. By removal of acetic acid with a high boiling point mixed solvent from the condensation polymerization of bisphenol A diacetate and the mixture of terephthalic/isophthalic acids, and while feeding the biphenyl/diphenyl ether mixed solvent under the boiling condition of the mixed solvent, a high molecular weight bisphenol A polyarylate was obtained. The polyarylate with a high molecular weight and narrow molecular weight distribution (Mw/Mn=1.6), and excellent appearance with a negligible discoloration was obtained. This new method should be called the reactive distillation condensation polymerization.