The macroscopic mechanical anisotropy (i.e., Young's modulus) of polymer solid may be explained in terms of the orientation of structural units having intrinsic mechanical anisotropy. In this paper, we propose a general method of theoretical calculation for the mechanical anisotropy of crystalline polymer solid using a transformation technique between two orientation distribution functions of structural units for two sets of Cartesian coordinates, i.e., a mutual conversion between two series of expansion coefficients of distribution functions.
On carring out the calculation of Young's modulus of bulk specimen, we took two ways based upon the difference in the representation of structural units and in the method of averaging them. One of them was made up by averaging the aggregation of structural units composed of anisotropic crystalline and isotropic noncrystalline phases on the basis of the homogeneous strain hypothesis, while the other by macroscopically combinning an averaged crystalline and an averaged noncrystalline unit on the basis of the homogeneous stress hypothesis.

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General mode of deformation and the morphology of fracture surface in polymers have been studied systematically from the point of view of fluidity of molecular chains.
Particularly for polystyrene, the mechanism of the propagation of fracture has been investigated in the light of morphology observed by the scanning type electron microscope.
Materials may be classified roughly into two groups, ductile one and brittle one, in terms of the fluidity. The ductility and the brittleness depend on the temperature and the speed of fracture.
In polymers, microfracture is first induced by uneven stress or defects in the material and then. Macrofracture occurs as the progress of the microfractures. Generally, crazing appears as the microfracture. In the case of ductile polymers, the craze grows into a necking, while in brittle polymer, e. g., polystyrene, the craze turns to a crack. The craze-induced fracture is a sort of ductile fracture and occurs along the boundary of the brittle and the ductile region giving rise to the so called mirror region. The ductile, mirror and brittle region present fibrous, granular and cleavage fracture, respectively.
In polystyrene, namely in the case of low fracture speed, the crack propagates within the crazed region. The mirror region offers many fine structures, characteristic of the condition of deformation. In the case of low fracture speed, the mirror region presents a fibrous fracture caused by the breakdown of molecular chains (in the middle of the craze). As the fracture speed increases, the crack tends to propagate along the interface between the craze and the undeformed matrix, giving rise to the separation of molecular chains. The mirror region has a granular fracture. When the fracture speed is very high, the fast-moving crack propagates in the interface. A large tensile stresses generated at the tip of the crack tends to relax momentarily and, accordingly, the speed of the cracking slows down, as the crack shifts to another interface, leaving pieces of the broken craze on the matrix. Thus the crack path traverses between two craze-matrix interfaces. The fragment takes various kinds of shapes and striations, depending on the speed of crack propagation. As the crack propagation speed becomes even larger, the crack traverses between two interfaces of different crazes. In this case, fracture surface shows a little larger shapes and the striations.
The results mentioned above are concerned with the shape of the mirror region or the mechanism of crack propagation in the craze. The mirror region seems to have a smooth surface by macroscopical observations. Microscopically the surface is generally granular, but the mirror near ductile region a fibrous fracture surface and the near brittle region, a cleavage surface.

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Graft copolymerization of methyl methacrylate onto silk was easily achieved by applying an aqueous Cu(II) - H₂O₂ initiator system. For example, a solution mixture of 10ml of H₂O, and each 2ml of 10^-2M Cu(II), 10^-1M H₂O₂ and 1ml of MMA was used. Effects of the concentrations of cupric salt, monomer, and hydrogen peroxide, and effects of the time and temperature of polymerization, and other conditions of the reaction were studied. The results obtained were as follows: (1) the yield of total polymer increases with increase of time and temperature of polymerization, (2) in an optimal condition examined, the rate of grafting is levelled off at 30 min., (3) the graft-on and the corresponding graft efficiency increase with increase in the temperature to a maximum level of grafting at 70°C, (4) total polymer-yield and the weight increase are approximately proportional to the concentration of monomer while the extent of grafting and graft efficiency have maximum values at the concentration of 1ml of MMA, (5) the weight increase and total conversion increase sharply with increase in the concentrations of H₂O₂ and Cu(II), and (6) none or little grafting occurs under atomospheric conditions.

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Effect of zinc fluoroborate (Zn(BF₄)₂ ) catalyst in the treatment of acrylic acid grafted polypropylene fabric with tris (1-aziridinyl) phosphine oxide (APO) was studied.
Weight increase (resin add-on) by APO-treatment and moisture regain of the polypropylene fabrics grafted with acrylic acid and further treated with dimethylformamide solution containing 5% APO are nearly equal regardless of the presence of Zn(BF₄)₂, while the weight increase of original ungrafted polypropylene fabric treated with APO and Zn(BF₄)₂ is higher than that of the sample treated without Zn(BF₄)₂. These facts suggest that the grafted acrylic acid chains have some catalytic action in this treatment and use of Zn(BF₄)₂ is not always necessary in the case of the grafted fabrics.
As Zn(BF₄)₂ has some deteriorative effect upon thermooxidative stability (measured by retention of warp tensile strength of the fabric after heat exposure at 100°C) of original polypropylene and the grafted polypropylene fabrics treated with APO-Zn(BF₄)₂ or Zn(BF₄)₂ alone, the elimination of use of Zn(BF₄)₂ catalyst in the treatment of the grafted fabrics with APO results in better thermooxidative stability of the fabrics and also some practical advantages, such as storage stability of the treating APO solution, etc.
Further experiments were made on the thermooxidative stability of the grafted polypropylene fabrics treated with phosphorus-containing compound (butyl acid phosphate-metal acetate system) or nitrogen-containing resins (methylol melamine and ethyleneurea), and no improving effects were observed with these treatments.

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Changes in the fine structure of wet-spun acrylic fibers of various polymer compositions and fiber structures during drying process were studied using a freeze-drying method. From the results it was proposed that the collapse is due to the attraction of capillaries. The capillary attraction mechanism explains the experimental results better than the mechanism, proposed by Dumbleton and Bell, attributing the collapse to conformational changes of stretched polymers. The results obtained are as follows.
1) Structural changes during drying take place from outer zone to inner zone of fibers, and uncollapsed fibrillar structures change into collapsed structures via intermediate structures which contain isolated voids. These three steps in structural changes are clearly visualized by using a phase microscope.
2) In every case of experiments, toluene densities of the fibers have the minimum value at water contents of about 5 to 25%. This is due to the appearance of closed voids in fibers.
3) Structural changes during drying process depend on polymer compositions and fine structures of fibers. For polyacrylonitrile fiber (PAN), the inner part retains a heterogeneous structure even after the high temperature drying. For acrylonitrile and sodium allyl sulfonate copolymer fiber (P(AN-SAS)), the low temperature drying gives rather a denser and more homogeneous structure at an intermediate stage of drying than high temperature drying, but in the final stage the high temperature drying gives a denser and more homogeneous structure. However, the acrylonitrile and methyl acrylate copolymer fiber (P(AN-MEA)) which have gross fibril-void structures, no collapse takes place by low temperature drying.
4) For PAN, P(AN-MEA) and P(AN-MEA-SAS) fibers, the degree of crystalline orientation decreases at first and increases in a final stage of drying, while for P(AN-SAS) fibers, it increases linearly with a progress of drying. In both cases, the size of crystallite increases with collapse. However, when uncollapsed opaque structures appear at the end of drying as seen in the case of P(AN-MEA), both the increase of orientation at the latter half part of drying period and growth of crystallite are not observed.

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The interaction of surface active agents with sericin has been studied with regard to reelability of cocoon in the process of raw silk production.
The following results were obtained.
1) Anionic and cationic surface active agents were adsorbed on sericin at co-ion regions respectively, and the adsorption of the later took place at pH2.5 where COOH groups of sericin scarecely dissociated.
2) In the co-ion region, the charge density of AgI sol particles covered with sericin became noticeable at about 10^-4M concentration of surface active agents, and at about cmc it increased remarkably. Also, the surface active agents which have the same polar groups increased the charge density of AgI sol particles covered with sericin at lower concentrations with the increase in chain length of alkyl groups.
3) The increment of charge density of AgI sol particles covered with sericin by adsorption of surface active agents was observed in the order of counter ion>isoelectric point>co-ion region. This was also found in the adsorption test using cocoon layers.
4) The effect of surface active agents on the swelling ratio of cocoon layer was in the order of co-ion>isoelectric point>counter ion region. In the counter ion region, the swelling ratio decreased at around the concentration at which the charge of sericin was neutralized with surface active agent, while in the co-ion region it increased remarkably at about cmc. Similar phenomena were found in the solubility test of sericin with sodium lauryl sulfate.
From these results, it is concluded that the interaction of surface active agent with sericin is due to both van der Waals force and electrostatic force (Coulomb's force) and the swelling ratio of cocoon layer treated with surface active agent is influenced by intermolecular electrostatic repulsion of sericin due to the adsorption as well as by lowering of the surface tention or contact angle etc.

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