A press dried paper manufacturing method has been investigated in terms of its quantifiable internal structure factors (sheet geometry). This method provides greater utilization of high-yield, low conformability fiber which is used for paperboard, and flexural rigidity is a very important property of paperboard made by the method. Despite the many studies on press drying, however, the reason for the higher mechanical properties provided is not yet clear. The present study resulted in one conceivable answer to this unsolved problem in terms of uneven mass distribution along the thickness direction of the press dried sheets.
Researching sheet geometry is very helpful to detect something hidden behind the mechanical properties. This study is a good example of the linking of mechanical properties with sheet geometry and has been investigated by this group for several years.

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The solvatochromism of the dyes, 4-nitroanilines (A and B), the azonia betain dye (C) was observed in nonpolar, polar aprotic and protic solvents. The solvents used were hexane, benzene, acetone, acetonitrile, ethanol and methanol. The shifts of the maximum wave numbers of these dyes by composition of binary mixture of solvents were analysed by assuming the selective solvation model. The results obtained indicate that the solvation of dyes is almost explained by the selective solvation model. The selectivities of solvents in solvation were analysed and discussed.

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Polyimide fibers were prepared from chlorinated rigid aromatic diamines and pyromellitic dianhydride (PMDA) by wet-spinning the N-methylpyrrolidone solutions of their precursor poly (amicacids) and then imidizing the fibers thermally or chemically. Random copolyimides had better drawability and gave stronger fibers than homopolyimides. For example, the chemically imidized copolypyromellitimide fiber of 2, 2'-dichlorobenzidine (Di-Cl-Bz)/benzidine (80/20) showed tenacity (T) 22.0 g/d, elongation (E) 1.7% and initial modulus (Mi) 1490 g/d. In general, the tensile properties of thermally imidized fibers were inferior to those of chemically imidized fibers, but random copolymers containing Di-Cl-Bz•PMDA as a main component yielded thermally imidized fibers having good tensile properties comparable to those of chemically imidized fibers. For example, T (g/d)/E (%)/Mi (g/d) of thermally imidized Di-Cl-Bz/2-chloro-p-phenylenediamine/PMDA (85/15/100) fiber were 19.1/1.4/1510.

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Rayon fabrics treated with ammonium sulfate were heated in the temperature range of 120 to 340°C in air and in nitrogen atmosphere, and the changes in the physical properties were investigated.
The results show that the temperature dependencies of the physical properties have inflections near 180°C. In the range of 120 to 180°C, dehydration and depolymerization seem to mainly proceed, being accompanied with weight loss as well as decrease in tensile strength. However, above around 180°C, the different but noteworthy changes were observed, namely, 1) marked increase in tensile strength, 2) release of carbon and introduction of nitrogen, 3) loss of solubility and changes in density. These may suggest that the introduced nitrogen plays an important role in recombining the splitted denatured molecules and hence in tightening the structure of the char.
Furthermore, an excellent flame-resistant fabric has been prepared by application of the procedure above mentioned. This fabric has a high L. O. I. value of 47, unmeltability, high hygro-scopicity and also excellent thermal and electrical insulatabilities, so that it seems to be useful in the fields where hazardous thermal environments exist.

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Rayon fibers treated respectively with ammonium sulfate, diammonium hydrogen phosphate and ammonium chloride were heated and carbonized in a nitrogen atmosphere at the rates of 1 to 5°C/min to various temperatures up to 1000°C. Changes in the physical properties in this process were investigated. In this range of heating rate, the carbonized rayon fibers obtained from the untreated one were so brittle that their strength properties could not be measured.
The tensile strength of the carbonized fiber varied depending on the kind of ammonium salts used for the treatment, the texture of starting material and also the heating rate. The results obtained suggest that; 1) ammonium sulfate serves for strengthening the carbon fibers, while neither diammonium hydrogen phosphate nor ammonium chloride bring about such an effect; 2) the higher degree of molecular orientation of the rayon precursor gives the greater strength to the resulting carbonized fiber; 3) the lower the heating rate, the stronger the resultant carbonized fiber.
Further, density, X-ray diffraction and elementary composition were measured of the samples heated at various temperatures. Based on these results, the effect of ammonium sulfate on the yield and the strength properties of the carbonized fiber has been discussed.

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The weave types of commercial woven fabrics were determined by analysing the two-dimensional arrangements of peak spots in the diffraction patterns. We confirmed experimentally the possibility of the discrimination of the three types of cloth weaves; plain, twill and satin. The relation between the design paper of the cloth weave and the diffraction pattern of the fabric is summarized as follows:
(1) The repeating unit of the cloth weave is observed in the unit cell made of the neighboring two warps and two fillings in the diffracted plane.
(2) The number of the harness is obtained by counting the number of peak spots in the unit cell.
(3) The design paper is determined by tilting clockwise the arrangement of the peak spots in the unit cell by an amount of 90°.

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Crystalline thin films of isotactic polystyrene (i-PS) were produced from their amorphous state by annealing. In the film annealed at 161°C for 7 minutes, crystalline lamellae are set in the edge-on position. A high-resolution electron microscopic image of the specimen showed the (300) lattice fringe (0.63nm) in a narrow band about 6nm wide. This width corresponds to the thickness of crystalline core in a lamella. A high-resolution image of the specimen annealed at 170°C for 2 hours revealed (hk0) lattice fringes, as is the case with a single crystal. This directly demonstrates the existence of single-crystal-like lamella in the flat-on position.
In the case of stretched thin film of high molecular weight i-PS which shows a typical fiber pattern on the electron diffraction pattern, the (110) lattice fringe (1.1nm) appeared in the long, slender region along the fiber axis This region seems to be ascribed to the “shish” crystal.

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The fading rates and color changes of some monochlorotriazine dyes were examined as applied on cellophane and cotton substrates with or without dye-substrate covalent bond. The fading rates and the color changes of the dyes dyed with the covalent bond on both the substrates are less remarkable than those of the analogues dyed without the covalent bond. The covalent bond seems to play an important role in the lightfastness of reactive dyes.

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