The structure of poly (β-alanine) polymerized in the solid state was investigated by means of X-ray diffraction and scanning electron microscopy. The reaction was carried out on a single crystal of β-alanine at 170°C for 40h in an evacuated, sealed test tube. The crystal structure of the poly (β-alanine) was assigned to I-type crystal of Nylon 3. The polymer chains were oriented towards the c-axis of the β-alanine monomer crystal. The scanning electron microscopic observations showed that the end view of the etched surface of poly (β-alanine) had mainly fibril-like morphology.
A remarkable decrease in breaking force of nylon 6 yarn after removing a constrain load during heat treatment has been found to depend on its temperature. This phenomenon is analyzed mainly with microscopic observation and discussed based on the relation between formation of kink band and thermal shrinkage. It is concluded that the breakage along kink band formed by rapid thermal shrinkage causes the above phenomenon. As a model for the above, a deformation mechanism for the kink band formed by uniaxial compression of nylon 6 bristle is discussed in comparison with that in fatigue process of nylon 6 fiber.
Breaking phenomenon in the successive biaxially drawing of Nylon 6 film with a higher deformation rate than 10, 000%/min is discussed based on the relation between the orientation state of hydrogen bonded sheets in the predrawn film and the formation of kink band by the secondary drawing. Consequently, it has been found that a uniaxially oriented structure of hydrogen bonded sheets of Nylon 6 can be formed in the predrawn film by blending 5-20wt% of poly (m-xylylene adipamide) and is most effective to decrease the number of breaking times during secondary drawing. Based on the above information, the industrial production of Nylon 6 film by the successive biaxially drawing method has been realized.
Drawing mechanisms are described for poly (ether-ether-ketone) (PEEK). Unoriented amorphous PEEK filaments were drawn at -115 to 300°C, and the effects of drawing temperature and draw ratio to the crystallinity and the molecular orientation of resulting filaments were analyzed. The elongation at break increased at about -100°C and -20_??_40°C. It also showed sharp peak at Tg. Then so-called super-draw was not observed. These temperatures corresponded to the mechanical relaxation peaks. The drastic drop of elongation above Tg was caused by crystallization in drawing process. The density of drawn filaments also decreased and showed minimum at 160 to 180°C. These results indicate microvoid formation in drawing. Above 280°C. drawn filaments became unhomogenous, while homogenous filaments were obtained at 300°C by drawing previously at 145°C. Above 0°C, density of filaments increased in drawing, nevertheless the crystallization was not observed below 140°C. It was caused by enthalpy relaxation with rearrangement of chain conformation. The birefringence of drawn filaments was almost independent of drawing temperature at -74_??_150°C. When the draw ratio was up to 1.5 times, molecular orientation could be approximated by rubber elasticity and no density change was observed. On the other hand, drawing behavior could be described by pseudoaffine model and the density increased in drawing at ratios more than 2 times.
A mixture of aramid and poly (ethyl oxazoline) was found to exhibit LCST (lower critical solution temperature) type phase behavior. A regularly phase-decomposed morphology developed by a temperature-jump from single-phase region to two-phase region above LCST and the morphology could be fixed by a rapid quench down to room temperature. We prepared a series of phase-decomposed specimens by changing the temperature and time of annealing and estimated the surface tension of the decomposed specimens by measuring the liquid contact angle at room temperature. Surface tension increased with time of annealing. Taking into account the result on the kinetics of phase decomposition by light scattering, the change in surface tension was ascribed to the progress of phase decomposition. Furthermore, FT/IR analysis revealed that this phenomenon is due to the dissociation of the hydrogen bonding type interaction between the component polymers.
The deposition of polymer latex onto nylon 6 fibers grafted with acrylic and methacrylic acids was studied as the function of pH and the degree of grafting. The polymer latices were hydrophobic polystyrene (PS) and hydrophilic polystyrene/2-hydroxyethyl methacrylate copolymer [P (St/HEMA10)] latices. In an aqueous solution of pH from 3 to 10 the ζ-potentials of both kinds of latices were negative, and the negative ζ-potentials of P (St/HEMA10) latex were smaller than those of PS latex because the slipping plane in electrical double layer was thrusted toward diffused layer by the water-soluble layer formed by poly-HEMA. On the acidic side, the amount of the deposits of both kinds of latices onto the ungrafted and the grafted fibers increased remarkably with a decrease in pH, but on the alkaline side, both kinds of latices were scarcely deposited onto these fibers. With an increase in the degree of grafting, the amount of the deposits of the latices onto the fibers reduced. The amount of the deposits of P (St/HEMA10) latex onto the grafting fibers were smaller than that of PS latex. These results suggest that the water-soluble polymer layers on the grafted fiber surface introduced by grafting and on P (St/HEMA10) latex surface play an important role on the deposition. The VT max, which was the energy barrier to deposite, was calculated from the theory of heterocoagulation. With an increase in the degree of grafting, the VT max increased, and the deposition rate constant Kc, calculated from the relation between the amount of the deposits and time, decreased. The relation between the values of kc and VT max indicates good correspondence.
The geometrical moiré patterns formed by superposing two figures of dots arranged at points of intersections of hexagonal fretworks have been investigated by using a personal computer. It was proved that numerous beautiful geometrical patterns were obtained by changing a rotation angle between the two figures, and some patterns were influenced by the selection of an original point for a rotation. When the original point was taken on a dot (o), the appearance period of patterns was 120° in the regular hexagonal arrangement system of dots (RH-system), and was 360° in the hexagonal arrangement system of dots (H-system). On the other hand, when the original point was taken at the center of arrangement dots (s), the appearance period of patterns was 60° in the RH-system, and was 180° in the H-system. The patterns at the original point s contain, besides the patterns at the original point s, many patterns different from those at the original point s, the number of which was the same as those at the original point s in the RH-system, and was one quarters of the total number in the H-system. In conclusion, it is very good technique for getting more patterns to select the original point with the longest appearance period of patterns.
A sewing needle is penetrated and withdrawn through fabrics during the sewing process. This penetration-withdrawal process causes an increase in the needle temperature by friction between the needle and the fabrics. A simultaneous measurement of force and temperature revealed that, in the process of machine sewing, the penetration resistance against the needle change with the rise in the temperature due to frictional heating. The penetration force with the change of the needle temperature, in case of using the polyester/cotton mixed fabrics, decreased until the needle temperature rised to 140°C. In case of polyester filament yarn fabrics, it showed a minimum value at about 80°C. On the other hand, the friction coefficient of the yarn constructing the sewn fabrics decreased with the increase in temperature. In case of polyester/cotton mixed fabrics, it decreased monotonously until 140_??_150°C, and remained constant after that. In case of polyester, it showed a minimum value at 80°C. From these facts, it is considered that the penetration force depends on the change of the friction coefficient with the rise in temperature.