Emulsion polymerization of styrene, butyl acrylate and vinyl acetate initiated with hydrogen peroxide-glyoxal, was performed to examine the effect of glyoxal on the rate of polymerization and the degree of polymerization. The rates of polymerization of styrene and butyl acrylate increased, but the degrees of polymerization decreased with the addition of glyoxal.
On the contrary, the emulsion polymerization of vinyl acetate was accompanied by the increase of both the rate of polymerization and the degree of polymerization with the addition of glyoxal.
It seemed that these effects of glyoxal were mainly due to the intermediate formation of 1: 1 compound of glyoxal with hydrogen peroxide. The polyvinyl acetate initiated with hydrogen peroxide-glyoxal was seemed to be incorporated with the glyoxal residues, and therefore their large molecular weights were ascribed to the reinitiation from the glyoxal residues in the polymer.

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Emulsion polymerization of vinyl acetate was carried out with hydrogen peroxide-glyoxal.
Polyvinyl alcohol which was prepared by the deacetylation of the obtained polymer, was oxidized by hydrogen peroxide in the acidic or alkaline medium.
The observed degradation of the polymer suggested that polyvinyl acetate obtained with hydrogen peroxide-glyoxal as initiator was the linear polymer containing half acetal structure.

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Single crystals of polyvinyl alcohol (PVA) were prepared by isothermal crystallization from 0.3% solution in triethylene glycol. Single crystals of PVA are parallelogrammic in shape. In many cases the ratio of the length of the longer side to the shorter side is fairly constant and is about 5. The lamella thickness estimated from the length of the shadow is 100-150Å. The acute angle of the parallelogram is about 55°. The spiral growths are often observed. The granular part is seen at the middle of the lamella and has a similar figure to the external form. Single crystals in triethylene glycol suspension were placed on the surface of a concentrated aqueous solution of PVA, which was allowed to solidify in a few days. The crystals were examined by replica technique. Observations show that PVA single crystals are corrugated platelets in solution. Electron diffraction shows that the chain axes are normal to the lamellae. The molecules must fold back and forth in some way through the platelet. The longer side of the parallelogram corresponds to the (101) plane and the shorter side to the (100) plane. The corrugations are almost parallel to the (301) plane.

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Parallelogrammic lamellar crystals represent the most characteristic habit of polyvinyl alcohol crystallized from dilute solutions. In addition, however, the crystals are observed which differ from the parallelogrammic in shape such as lath-shaped, partially lath-shaped, Y-shaped and Lshaped lamellae. Measurements of the diffraction patterns of the lath-shaped and the partially lath-shaped lamellae show that the patterns arise from the superposition of the diffraction patterns given by two monoclinic lattices of the type observed for the parallelogrammic crystal and that those are the (101) reflection twins. The diffraction spots of the Y-shaped lamella nearly correspond to the constructed pattern of the reciprocal lattices of the (100) and the (001) reflection twins. It is confirmed that the composition plane having the re-entrant angle of 110° is the (100) twinned plane and that having re-entrant angle of 75° is the (001) twinned plane. In the Lshaped lamella, two kinds of lamellae with an angle of about 110° or 140° were observed. From the diffraction pattern and the shape of the crystal, it is concluded that the L-shaped lamella with an angle of about 110° is the (100) reflection twin and that the L-shaped lamella with an angle of about 140° is the (101) reflection twin. The composition plane is almost in the middle of the crystal. Corrugations intersected at the composition plane are observed. The granular parts having a similar figure to the external form are observed in the middle of the crystal.

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Electron diffraction patterns from a single crystal of polyvinyl alcohol (PVA) are sharp, but rapidly deteriorated and finally disappeared under the effect of electron bombardment within the microscope, while the shape of the crystals remained unaltered. The spacings of the PVA crystals are gradually increased by electron bombardment. The (101) planes are more affected than the (101) planes. The PVA crystals have a tendency to change from the monoclinic to the orthorhombic cell by electron bombardment. Therefore, electron diffraction pattern must be quickly taken in order to avoid damage due to the electron beam. Then the cell constants of the PVA crystals can be precisely determind as α=7.81±0.02Å, c=5.43±0.01A, β=91°30′±15′. The length of the c-axis obtained from the electron diffraction of the single crystal is slightly shorter than those from X-ray diffraction of PVA fibers.

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Elastic modulus of the crystal lattice parallel to the chain axis (E_l), for polyethylene oxide (PEO) was determined by an X-ray diffraction method. The modulus was found to be
PEO: E_ι=10×10⁴kg/cm² (21±1°C).
The value is about twice as large as the value calculated by Enomoto et al.((4.6-4.9)×10⁴kg/cm²). However, using the conformational model and the force constants of PEO reported recently by Tadokoro et al., we obtained E_ι-value of (7.8-9.2)×10⁴ kg/cm² which showed good agreement with the observed value.
The observed E_ι-value of PEO is the smallest among those so far found for polyethers. The elastic moduli of polyethers expressed by a general formula -[-(CH₂) _m-O-] _n, were discussed in terms of the chain skeleton conformation in the crystalline state.

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Elastic modulus of the crystal lattice parallel to the chain axis (E_ι), for polytetrahydrofuran (PTHF) was determined by an X-ray diffraction method. The modulus was found to be
PTHF: E_ι=55×10⁴kg/cm² (20±1°C).
Imada et al. and Cesari et al. recently reported that the molecular chain of PTHF assumed a planar zig-zag conformation in the crystalline state and a small cross-sectional area of 17.1×10^-16cm². The force constants of bond-stretching and of bond-bending for C-O and C-O-C are reported to be rather greater than those for C-C and C-C-C. This seems to make it difficult to understand the result for PTHF which showed much lower value of E_ι compared with that for polyethylene (E_ι=240×10⁴kg/cm²). One of explanations for this may be that the chain of PTHF does not assume fully extended structure in the crystalline state.

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In the preceding paper a formal theory for the terminal region of non-linear stress relaxation was proposed. In the present study the usual concept of distribution of relaxation times was introduced and the relaxation phenomena were analyzed in terms of the relaxation time τ_m⁰ and the “non-linear coefficient”η_m* analogous to the zero shear viscosity η_m⁰ of the slowest mechanism.
After the non-Newtonian flow the strength of the slowest relaxation mechanisms seemed to be depressed, but the slowest relaxation time itself independent of the shearing rate.
Generally shear break-downs of the secondary structures may be a main factor of non-linear viscoelastic behaviors of the solutions studied.

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A polymethylmethacrylate cast sheet was stretched uni- or bi-axially with a thermoforming apparatus. Longitudinal stretch was given in ratios μ, between 1 and 4, and transverse stretch in ratios between 0.6 and 2.5. Maximum tensile strength, T_λ or T_μ and tensile breakage energy, P_λ or P_μ, were measured on 60mm×5mm rectangular test piece cut out along λ- or μ-direction and notched with a razor in 0.02-0.05mm depth at the middle point of the longer edge. Biaxial reinforcement was found only for the stretched sheets of about λ=μ=2.0. Solvent-stress-crazing was examined on (20-30) mm×5mm test piece bent to a state of 0.5 or 1.0% maximum outer fibre strain in saturated isopropanol vapour at 21°C by observing appearance of crazing after 24 hrs (0.5% strain corresponding approximately to 2000 psi stress in MIL-P-8184). Craze resistance increases with increase in stretch ratio in the stressed direction of the test piece but is independent of stretch ratio in the other directions. Three principal birefringences, (n_μ-n_ν), (n_ν-n_λ), and (n_λ-n_μ), were found to correlate linearly with their corresponding principal stretch ratio differences, (μ-ν), (ν-λ), and (λ-μ); and more closely than with the differences of their squares, (μ²-ν²), (ν²-λ²), and (λ²-μ²), in Treloar's theory. All experimental results could be plotted satisfactorily on a logarithmic stretch ratio plane, (logλ+logμ+logλ=0).

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