The effect of a small amount of Polymethylmethacrylate (PMMA) additive on the fiber structure formation of poly(ethylene terephthalate) (PET) has been studied by means of birefringence, tensile properties, wide-angle-X-ray scattering, and DSC profiles. The investigations have been carried out under various spinning speeds (1000-5000m/min) and temperatures (275-295°C). A small amount of PMMA, which is immiscible with PET, suppressed the structure formation of PET at spinning speeds higher than 3000m/min, in that the birefringence and the melting point became lower and the wide angle X-ray scattering pattern was not clear compared with those of pure PET. Higher spinning temperature led to higher tenacity, the smaller elongation at break, and higher birefringence in PET/PMMA blend fiber. These tendencies were quite opposite to those in pure PET. To understand the cause of the suppression of structure formation of PET and the opposite tendencies with respect to the increase in spinning temperature by the presence of a small amount of PMMA, the melt viscosity of PET/PMMA blend, the deformation of PMMA particles after spinning were examined. Also the effect of solidification temperature of blend polymer on the orientation was investigated by using some PMMAs having different Tgs. These results suggested that PMMA does not work as plasticizer, and that the dispersed PMMA particles at higher spinning temperature had larger aspect ratio (L/D) compared with those of spun at low temperature. The molecular orientation decreased with increasing Tg(80-116°C) of PMMA. Taking these facts into consideration, the major cause for the less oriented PET(Tg=65°C) structure was considered that the formation of PET fiber structure should be finished before the solidification of PMMA due to its higher solidification temperature compared with those of PET itself, and the elongation flow of PET on the spinning line was restricted by the PMMA which deformed in parallel with PET.
Mechanical properties measured by tensile test of Nylon6 fibers with various diameters have been examined in standard, wet, and water-immersed conditions. Tensile test in wet condition was performed under JIS L 1030. Tensile test in water-immersed condition was applied to the fibers dipped in water. Diameters of the fibers used for the tests were 2.5(super micro fiber), 9.1(micro fiber), 24 and 82μm. An influence of water evaporation to the mechanical properties measured in wet condition has been discussed, compared with those obtained in water-immersed condition.
Cotton and regenerated cellulose fiber lyocell were treated with liquid ammonia (NH3), and subsequently processed with dry heat, high temperature (HT) steam at atmospheric pressure and high pressure (HP) steam at 0.22 MPa and hot water at various temperatures. The effects of the processing on crystal modification, crystallinity, moisture regain, water absorption, and dyeing property was investigated. The diffraction intensity of cellulose IIII crystallite of the cotton fiber decreased with increasing a temperature of the hot water, while cellulose I crystallite increased by the treatment. On the other hand, dry heat treatment was not effective for the modification of cellulose IIII crystallite generated at the NH3 treatment. Change of the crystallite phase by the HT and HP steamings occurred less than that of the hot water and more than dry heat. Furthermore, an intensity of the cellulose IIIII crystallite of the NH3 treated lyocell took place no change not only with subsequent hot water but also with dry heat processing. Moisture regain, water absorption, and equilibrium dye uptake of the cotton were decreased by subsequent hot water processing, whereas thoseof the lyocell were almost unchanged.
Mercerization is one of the most common wet processing of cotton materials to improve the dyeing property. On the other hand, it is known that the treatment brings about a stiff hand. So, hot mercerization is expected to improve the soft hand. Scoured and bleached cotton fiber and fabric were mercerized for 5 min at a temperature of 20°C to 100°C with 20% sodium hydroxide aqueous solution. The X-ray diffraction, apparent dyeing rate and equilibrium dye uptake were measured. Although crystallite of the cotton fiber was transformed from cellulose I to cellulose III with a decreasing of the mercerizing temperature, especially by the treatment under 60°C, the diffraction pattern of the cotton fabric as fiber assembly was not changed to cellulose III.Apparent dyeing rate of the fiber increased with a decrease of the mercerizing temperature, whereas an increase of the rate of the fabric was considerably small compared with that of the fiber. Also, there was no difference among the mercerizing temperature. Therefore, it seems that mercerization of the fiber proceeds easily and transformed from cellulose I to cellulose III, while mercerization of the fabric as fiber assembly is difficult to penetrate sodium hydroxide like a fiber, because of the tight structure of the fiber assembly. Therefore, is clear that mercerization of the fabric is quitely different with that of the fiber. Hot mercerization is not always effective to decrease the KES parameters in shearing and bending behaviors.
Atom transfer radical polymerization (ATRP) of styrene and methyl methacrylate (MMA) was carried out using chloroacetyl cellulose and cellulose acetate (CA) as an initiator in glyme. ATRP was also done using 2-chloropropionyl cellulose and CA. The cellulosic graft copolymers were prepared through the activation of initiators by the metal complex consisted of CuBr and pentamethyldiethylenetriamine (PMDATA). Increase in the degree of substitution (DS) of chloroacyl groups led to increase in grafting ratio. Grafting efficiency was over 80 % with both monomers. 2-chloropropionyl cellulose and CA revealed higher reactivity than chloroacetyl derivatives nevertheless their much lower DS of 2-chloropropionyl groups. Though styrene was not polymerized below 100°C by any initiators used, it became feasible to be polymerized at 80°C by mixing with MMA which was easily polymerized at this temperature. Copolymers of styrene and MMA was grafted in this case. CA-graft-PMMA copolymers having grafting ratio over 80 % were dissolved in acetone and dimethyl sulfoxide.
The influence of ferrous contaminations or keratin treatments on the degradation of bast fibers induced by the irradiation with ultraviolet rays was investigated. The ferrous contaminations accelerated the degradation. The treatments with keratin were effective for suppression of the degradation, and enhanced the tensile strengths of bast fibers.